Metal-doped ruthenium oxide nanometer material, and preparation method and use thereof

Abstract

The disclosure relates to a metal-doped ruthenium oxide nanometer material and methods of its preparation and use. The metal-doped ruthenium oxide nanometer material may be an acid-insoluble metal oxide-doped ruthenium oxide nanometer material or a transition metal-doped ruthenium oxide nanometer material. The molecular formula of the metal-doped ruthenium oxide nanometer material is MxRu1-xO2, wherein M is selected from niobium, titanium, zirconium, hafnium, tungsten, molybdenum, and tantalum; or a transition metal selected from Cr, Mn, Ge, In, Sn, Sb, Nb, Ti, Zr, Hf, W, Mo, Ta, and Pt. The dopant metal is highly uniformly dispersed in a ruthenium oxide material, such that active-site ruthenium is well controlled, and the stability and activity of the material during an oxygen evolving reaction in water hydrolysis are improved.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of International Pat. Appl. No. PCT / CN2022 / 113508, filed on Aug. 19, 2022, which claims the benefit of Chinese Pat. Appl. Nos. 202210530718.6, filed on May 16, 2022, and 202210932935.8, filed on Aug. 4, 2022, all of which are incorporated herein by reference as if fully set forth herein.TECHNICAL FIELD

[0002] The present invention belongs to the technical field of inorganic advanced nanometer materials, and particularly relates to a metal-doped ruthenium oxide nanometer material and methods of its a preparation and use.BACKGROUND

[0003] With the consumption of traditional fossil energy and the increasingly severe environmental pollution issue caused by its combustion, carbon dioxide emissions are increased, the goals of “peak carbon dioxide emissions” and “carbon neutrality” still face severe challenges, and therefore, developing new sustainable clean energy to replace fossil fuels is of the highest priority. At present, solar energy, wind energy, bioenergy, tidal energy, and hydrogen energy are developed into relatively mature new alternative energy. Among them, hydrogen energy, as clean energy, has high energy density, is clean and pollution-free, and increasingly receives a widespread attention. Meanwhile, there are numerous sources of hydrogen energy, including fossil fuel hydrogen production, carbon capture hydrogen production, water electrolysis hydrogen production, etc. Among them, water electrolysis hydrogen production is a relatively simple and mature technology, among numerous production processes. Water electrolysis hydrogen production may be classified into an alkaline water electrolysis hydrogen production technology (ALK), a solid oxide electrolysis cell technology (SOEC), and a proton exchange membrane water electrolysis technology (PEM). Compared to ALK technology, PEM hydrogen production has a higher working current density (>1 A / cm2), higher overall efficiency (74% to 87%), a higher hydrogen volume fraction (>99.99%), a higher gas production pressure (3 MPa to 4 MPa), and a faster dynamic response speed. It can adapt to the volatility of renewable energy power generation, and is considered as a highly promising water electrolysis hydrogen production technology.

[0004] However, the anode in a PEM electrolytic system may include a transition metal catalyst such as iron, cobalt, and nickel, which can dissolve quickly and lose stability due to locally super-strong acidity and oxidation. Iridium oxide is currently a commercially-used catalyst for PEM due to its extremely high acidic oxygen evolution stability. However, its increasingly soaring price and scarcity make it difficult to use on a large scale and thus meet future demands for hydrogen energy. With the successful preparation of proton exchange membranes, the cost of membranes will significantly decrease in the future. Seeking alternative acidic oxygen evolution catalysts with good activity and stability is the key to reduce the cost of pure water electrolysis.

[0005] Ruthenium oxide has extremely high acidic oxygen evolution activity, but a potential for oxidation to RuO4 is 1.33 V (relative to a standard hydrogen electrode), which is within the working potential of an oxygen evolving reaction, thereby oxidizing the ruthenium in the oxygen evolving process, ultimately resulting in the production and dissolution of high-valence oxides of ruthenium in the electrolyte solution, which finally leads to the loss of active sites and the degradation of catalytic oxygen evolving reaction performance. However, its lower price makes designing ruthenium-based oxygen evolution catalysts with high activity and stability very promising and challenging.

[0006] In recent years, researchers have made many efforts to improve the oxygen evolution activity and stability of ruthenium-based catalysts. For example, doping transition metals such as iron, cobalt, nickel and chromium in ruthenium oxide, introducing defects within ruthenium oxide, regulating the morphology of ruthenium oxide, and loading ruthenium oxide onto a stable substrate ultimately achieve changes in the electronic structure of ruthenium oxide, thereby improving its adsorption with oxygen-containing intermediates, and further improving the electrocatalytic oxygen evolution performance and stability. However, the issues of low activity and unacceptably low stability have not been resolved yet.SUMMARY

[0007] The present invention intends to solve the above problems.

[0008] The present invention concerns at least in part an acid-insoluble metal oxide-doped ruthenium oxide nanometer material that may be prepared by a sol-gel method, a solvothermal method and a ball milling method, and the nanometer material exhibits super-high activity and stability when used as an acidic oxygen evolution electrode material.

[0009] A first aspect of the present invention concerns an acid-insoluble metal oxide-doped ruthenium oxide nanometer material having the molecular formula MxRu1-xO2, wherein M is a metal having an acid-insoluble oxide, and is selected from niobium, titanium, zirconium, hafnium, tungsten, molybdenum and tantalum.

[0010] For example, the metal may be one, two, three, four, five, six or seven of niobium, titanium, zirconium, hafnium, tungsten, molybdenum and tantalum.

[0011] Herein, an acid-insoluble metal oxide is defined as a metal oxide with a solubility of less than 10−5 mol / L or g / L in dilute inorganic acid (i.e., an aqueous 10% to 20% by weight or volume solution of a concentrated hydrohalic acid, without other added components that can react with or solubilize the metal oxide) at ambient or room temperature.

[0012] Preferably, in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material, the metal is doped into a ruthenium oxide lattice, and atoms of the metal replace ruthenium atoms in the lattice. In addition, when the acid-insoluble metal oxide-doped ruthenium oxide nanometer material has a ruthenium oxide crystal structure, the metal is uniformly dispersed in the ruthenium oxide crystal structure.

[0013] Preferably, the acid-insoluble metal oxide-doped ruthenium oxide nanometer material comprise nanoparticles with a rough and porous surface. The nanoparticles may have a size of 5 to 2000 nm, preferably 50 to 200 nm.

[0014] Preferably, the metal and the ruthenium are uniformly dispersed in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material.

[0015] Preferably, in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material, the metal is present in a ratio of 1% to 50%, based on a total quantity of moles or atoms of the metal and the ruthenium in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material. The ratio of the metal in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material may be calculated using the formula: N1 / (N1+N2), where N1 is a molar weight of the acid-insoluble metal oxide or an atomic weight of the metal, and N2 is a molar weight of the ruthenium oxide or an atomic weight of ruthenium.

[0016] Preferably, in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material, the ruthenium oxide has 101 crystal planes and 110 crystal planes. A distance between the 101 crystal planes is 0.256 nm, and a distance between the 110 crystal planes is 0.316 nm or 0.317 nm.

[0017] In conventional ruthenium oxide, a distance between the 101 crystal planes is 0.254 nm, and a distance between the 110 crystal planes is 0.315 nm.

[0018] In terms of a lattice distance, the present acid-insoluble metal oxide-doped ruthenium oxide nanometer material has a slightly greater lattice distance than a conventional ruthenium oxide material.

[0019] A second aspect of the present invention concerns a method of preparing the acid-insoluble metal oxide-doped ruthenium oxide nanometer material described in the first aspect. The preparation method may comprise a sol-gel method that includes the following steps:

[0020] Placing a ligand into a solution containing an acid-insoluble metal oxide source and a ruthenium source to obtain a mixture, sealing and mixing the mixture in a container at a constant temperature for several hours (e.g., 1-48 hours), then opening the container, volatilizing any solvent (e.g., in the container), such as by drying, distillation and / or vacuum (e.g., freeze-drying), and removing (e.g., scraping off from the container) a remaining solid (e.g., a powder) to obtain a metal complex precursor; and

[0021] Placing the metal complex precursor into a muffle furnace, raising a temperature (e.g., of the muffle furnace) to a reaction temperature and maintaining the reaction temperature for several (e.g., 1-24) hours, and removing a product (optionally after cooling, which may be natural) to obtain the acid-insoluble metal oxide-doped ruthenium oxide nanometer material (which may also comprise a powder).

[0022] Preferably, the acid-insoluble metal oxide source is selected from a metal chloride, a metal organic carboxylate (e.g., a metal oxalate or metal ammonium oxalate), and a metal carbonyl compound.

[0023] The ruthenium source may comprise a ruthenium chloride compound, a ruthenium carbonyl compound, a ruthenium diketonate (e.g., ruthenium acetylacetonate, ruthenium malonate, etc.), or ruthenium nitrosylnitrate.

[0024] The ligand may comprise a polymer containing a plurality of coordinatable groups.

[0025] More preferably, the polymer containing the plurality of coordinatable groups is selected from polyvinyl alcohol, polyethylene glycol, polyethylene diamine, polylactic acid, polyvinylpyrrolidone, polypyridine, polypyrrole and polyamides.

[0026] The solution containing the acid-insoluble metal oxide source and the ruthenium source may be an aqueous solution or an alcoholic solution, as long as dissolution of the metal oxide source and the ruthenium source can be achieved.

[0027] Preferably, the mixture has a concentration of the acid-insoluble metal oxide source of 0.01 to 1 mol / L, and a concentration of the ruthenium source of 0.1 to 1 mol / L. A concentration of the complex may be from 1 to 40 g / L.

[0028] Preferably, the constant temperature ranges from 70° C. to 150° C., and the mixture may be sealed and mixed for a time that ranges from 10 to 15 hours.

[0029] Preferably, the reaction temperature is raised at a rate that ranges from 1° C. / min to 10° C. / min, the reaction temperature ranges from 400° C. to 600° C., and the reaction temperature is maintained for a time that ranges from 3 hours to 6 hours.

[0030] A third aspect of the present invention concerns a method of preparing the acid-insoluble metal oxide-doped ruthenium oxide nanometer material described in the first aspect. The preparation method may comprise a solvothermal method that includes:

[0031] Placing a solution of an acid-insoluble metal oxide source and a ruthenium source into a hydrothermal reactor, optionally mixing or applying ultrasound until the acid-insoluble metal oxide source and the ruthenium source are completely dissolved, adding an alkali source to obtain a reaction liquid, placing the hydrothermal reactor into a constant temperature oven, heating the oven to a temperature of 100° C. to 200° C., maintaining the temperature for 8 to 16 hours, optionally taking out the hydrothermal reactor and cooling (e.g., naturally) to room temperature, and removing a reaction product (e.g., a sediment, optionally after washing and drying) to obtain powder; and

[0032] Placing the powder into a porcelain boat and placing the porcelain boat into a muffle furnace, raising a temperature of the muffle furnace at a rate of 5 to 10° C. / min to a reaction temperature of 400° C. to 600° C., maintaining the reaction temperature for 2 to 8 hours to obtain the acid-insoluble metal oxide-doped ruthenium oxide nanometer material (which may be a black powder), optionally after cooling (e.g., naturally) the acid-insoluble metal oxide-doped ruthenium oxide nanometer material.

[0033] In some embodiments, the reaction liquid has a concentration of the acid-insoluble metal oxide source that ranges from 0.001 mol / L to 1 mol / L, a concentration of the ruthenium source that ranges from 0.1 mol / L to 1 mol / L, and a concentration of the alkali source of 0.5 to 4 mol / L.

[0034] The acid-insoluble metal oxide source may be selected from a corresponding metal chloride, a corresponding metal organic carboxylate (e.g., a metal oxalate or metal ammonium oxalate), and a corresponding metal carbonyl compound.

[0035] The ruthenium source may comprise a ruthenium chloride compound, a ruthenium diketonate (e.g., ruthenium acetylacetonate), a ruthenium carbonyl compound or ruthenium nitrosylnitrate.

[0036] The alkali source may comprise urea and / or ammonium hydroxide.

[0037] The solution of the acid-insoluble metal oxide source and the ruthenium source may be an aqueous solution or an alcoholic solution, as long as dissolution of the acid-insoluble metal oxide source and the ruthenium source can be achieved.

[0038] A fourth aspect of the present invention concerns a method of preparing the acid-insoluble metal oxide-doped ruthenium oxide nanometer material described in the first aspect. The preparation method may comprise a ball milling method that includes:

[0039] Placing ruthenium oxide and an acid-insoluble metal oxide into a ball milling tank, ball milling for 3 to 6 hours, repeating the ball milling 2 to 3 times to obtain a precursor powder, placing the precursor powder into a porcelain boat, placing the porcelain boat into a muffle furnace, raising a temperature of the muffle furnace at a rate of 5 to 10° C. / min to a reaction temperature of 400° C. to 800° C., maintaining the reaction temperature for 6 to 12 hours and optionally cooling (e.g., naturally) to obtain the acid-insoluble metal oxide-doped ruthenium oxide nanometer material (which may be a black powder).

[0040] A mole ratio of the ruthenium oxide to the acid-insoluble metal oxide may be 99:1 to 1:1.

[0041] A fifth aspect of the present invention concerns a use of the acid-insoluble metal oxide-doped ruthenium oxide nanometer material described in any aspect as an electrode material. In other words, the present invention also concerns an electrode comprising the acid-insoluble metal oxide-doped ruthenium oxide nanometer material according to any aspect of the invention.

[0042] Preferably, the acid-insoluble metal oxide-doped ruthenium oxide nanometer material is in an anode adapted for electrolysis of water (e.g., for oxygen evolution in an acidic water electrolysis apparatus).

[0043] The present invention also concerns a transition metal-doped ruthenium oxide nanometer material that may be prepared by a hydrothermal method. The nanometer material exhibits super-high activity and good stability when used as an oxygen evolution electrode material in an acidic water electrolysis apparatus.

[0044] A sixth aspect of the present invention concerns a transition metal-doped ruthenium oxide nanometer material. The transition metal-doped ruthenium oxide nanometer material has a molecular formula of MxRu1-xO2; wherein M is a transition metal selected from Cr, Mn, Ge, In, Sn, Sb, Nb, Ti, Zr, Hf, W, Mo, Ta, and Pt.

[0045] Preferably, the transition metal-doped ruthenium oxide nanometer material includes a ruthenium oxide crystal lattice, and atoms of the transition metal replace ruthenium atoms in the crystal lattice and may be uniformly dispersed in the ruthenium oxide lattice.

[0046] Preferably, the transition metal-doped ruthenium oxide nanometer material comprises or consists essentially of nanoparticles with rough surfaces. The nanoparticles may have a size of 5 to 2000 nm.

[0047] Preferably, the transition metal and ruthenium are uniformly dispersed in the transition metal-doped ruthenium oxide nanometer material.

[0048] Preferably, in the transition metal-doped ruthenium oxide nanometer material, the transition metal is present in a ratio of 1% to 50%, based on a total quantity of moles or atoms of the transition metal and the ruthenium in the transition metal-doped ruthenium oxide nanometer material. The ratio of the transition metal in the transition metal-doped ruthenium oxide nanometer material may be calculated using the formula N1 / (N1+N2), where N1 is a molar weight of the acid-insoluble metal oxide or an atomic weight of the metal, and N2 is a molar weight of the ruthenium oxide or an atomic weight of ruthenium.

[0049] A seventh aspect of the present invention concerns a method of preparing the transition metal-doped ruthenium oxide nanometer material described in earlier aspects. The preparation method may comprise a hydrothermal method that includes:

[0050] Forming a solution containing a soluble transition metal source and a soluble ruthenium source, adding a polymer containing a plurality of coordinatable groups to the solution to obtain a mixture, then transferring the mixture into a hydrothermal reactor, heating the mixture for several (e.g., 1-24) hours in a constant temperature oven, optionally cooling (e.g., naturally) to room temperature, and washing, centrifuging, and drying (e.g., the reacted mixture) to obtain a transition metal precursor; and

[0051] Placing the transition metal precursor into a muffle furnace, raising a temperature of the muffle furnace to a reaction temperature, maintaining the reaction temperature for several (e.g., 1-24) hours, then removing a resulting product (optionally after natural cooling) to obtain the transition metal-doped ruthenium oxide nanometer material (which may be a powder).

[0052] Preferably, the transition metal source is one or more of a transition metal chloride, a transition metal high-valence compound, a transition metal organic carboxylate (e.g., a transition metal oxalate), and a transition metal carbonyl compound.

[0053] The ruthenium source may be one or more of a ruthenium chloride compound, a ruthenium diketonate (e.g., ruthenium acetylacetonate), a ruthenium carbonyl compound or ruthenium nitrosylnitrate.

[0054] The polymer containing the plurality of coordinatable groups may be one or more of polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene diamine, polylactic acid, polypyridine and a polyamide.

[0055] The solution containing the transition metal source and the ruthenium source may be an aqueous solution or an alcoholic solution to achieve dissolution of the transition metal source and the ruthenium source.

[0056] Preferably, a soluble chromium source is potassium dichromate or chromium chloride.

[0057] Preferably, a soluble manganese source is potassium permanganate or manganese chloride tetrahydrate.

[0058] Preferably, a soluble germanium source is germanium chloride.

[0059] Preferably, a soluble indium source is indium chloride.

[0060] Preferably, a soluble tin source is tin tetrachloride pentahydrate.

[0061] Preferably, a soluble antimony source is antimony chloride.

[0062] Preferably, a soluble niobium source is niobium chloride, niobium oxalate, or niobium pentoxide.

[0063] Preferably, a soluble titanium source is titanium chloride.

[0064] Preferably, a soluble zirconium source is zirconium chloride.

[0065] Preferably, a soluble hafnium source is hafnium oxide.

[0066] Preferably, a soluble tungsten source is tungsten oxide.

[0067] Preferably, a soluble molybdenum source is molybdenum chloride.

[0068] Preferably, a soluble tantalum source is tantalum chloride.

[0069] Preferably, a soluble platinum source is chloroplatinic acid.

[0070] Preferably, the mixture (e.g., in the hydrothermal method) has a concentration of the transition metal source of 0.001 to 1 mol / L, a concentration of the ruthenium source of 0.1 to 1 mol / L, and a concentration of the polymer of 1 to 50 g / L.

[0071] Preferably, the temperature of the constant temperature oven is 100° C. to 180° C., and the mixture is in the constant temperature oven for a time of 4 to 10 hours.

[0072] Preferably, the temperature of the muffle furnace is raised at a rate of 1 to 10° C. / min, the reaction temperature is 300° C. to 500° C., and the reaction temperature is maintained for 3 to 5 hours.

[0073] An eighth aspect of the present invention concerns a use of the transition metal-doped ruthenium oxide nanometer material described in any of the earlier aspects in an electrode. In other words, the present invention also concerns an electrode comprising the transition metal-doped ruthenium oxide nanometer material.

[0074] Preferably, the transition metal-doped ruthenium oxide nanometer material is in an anode adapted for electrolysis of water (e.g., for oxygen evolution in an acidic water electrolysis apparatus). Preferably, the transition metal-doped ruthenium oxide nanometer material improves the activity and stability of the material (e.g., an anode comprising the transition metal-doped ruthenium oxide nanometer material) in a water electrolysis reaction.

[0075] The above technical solutions may be combined freely on the premise of no conflict.

[0076] Compared to the prior art, the present invention has the following beneficial effects:

[0077] The acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention has the following advantages:

[0078] (1) The acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention is reported the first time, the metal atoms of the acid-insoluble metal oxide is doped into the lattices of the ruthenium oxide and replace atoms of ruthenium in the lattices. Doping of the acid-insoluble metal oxide does not break the intrinsic structure of the ruthenium oxide, and the crystal structure of rutile-phase ruthenium oxide is still maintained substantially perfectly. Meanwhile, the metal of the acid-insoluble metal oxide is highly uniformly dispersed in the material, and no impure-phase acid-insoluble metal oxide is generated, such that active-site ruthenium is well controlled, and stability is kept during an oxygen evolving reaction during water hydrolysis.

[0079] (2) The acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention is uniform in particle size and porous, and the method of synthesis is simple. The acid-insoluble metal oxide-doped ruthenium oxide nanometer material further lowers the amount of precious metal ruthenium used, after doping of the acid-insoluble metal oxide, the ruthenium-oxygen bond covalency is weakened due to the introduction of the other metal, the active-site ruthenium is at a lower valence state, and the obtained acid-insoluble metal oxide-doped ruthenium oxide exhibits extremely high activity and stability in an acidic water electrolysis oxygen evolution anode.

[0080] In particular, in the material of the present invention, acid-insoluble metal oxides have the advantages of 1, not dissolving in an acidic electrolyte solution and keeping stability of the material, and 2, weakening the ruthenium-oxygen bond covalency due to the introduction of the other metal, and the reasons are as follows: (1) the acid-insoluble metal oxides have very high acidic stability and oxidation resistance properties, active sites can be stably controlled in the oxygen evolution process, and the stability of the ruthenium oxide is improved; and (2) according to the adsorption theory, adsorption of the other metal for oxygen-containing intermediates is weak, and through doping into the lattices of the ruthenium oxide, adsorption of the ruthenium sites for the oxygen-containing intermediates improves, finally achieving the improvement of the activity at the ruthenium sites.

[0081] Iron, cobalt, nickel and chromium, which are commonly doped in ruthenium oxide at present, do not have the above-mentioned effects. Doping of iron, cobalt, nickel and chromium is usually because their valence states are low and do not match with tetravalence of the ruthenium oxide, which causes an oxygen defect, changes the oxygen evolving reaction mechanism into a lattice oxygen oxidation mechanism, and finally improves the oxygen evolving reaction activity, but the instability of the oxygen defect weakens the catalyst stability.

[0082] (3) In terms of activity: when the acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention is used as an acidic water electrolysis oxygen evolution anode material, and the doping amount of the metal corresponding to the acid-insoluble metal oxide is 1 at % to 50 at % (at % is a molar or atomic mass fraction of metal, based on the total molar or atomic mass of all metals in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material), the intrinsic activity is high. Specifically, it can be seen from FIG. 7 that the acid-insoluble metal oxide-doped ruthenium oxide nanometer material obtained in Example 1 and Example 2 has good water electrolysis oxygen evolution performance, and the overpotential at a current density of 10 milliampere per square centimeter is 196 millivolts and 219 millivolts, which are lower than commercial ruthenium dioxide (320 millivolts).

[0083] (4) In terms of stability: when the acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention is used as an acidic water electrolysis oxygen evolution anode material, under the working conditions of high current densities (e.g., 100 to 200 mA cm−2), its constant current polarization curve may be still kept stable for 360 h, which proves that the acid-insoluble metal oxide-doped ruthenium oxide nanometer material has extremely good acidic oxygen evolving reaction stability.

[0084] (5) The present invention has three preparation methods: a sol-gel method, a solvothermal method and a ball milling method. The sol-gel method is synthesis in a simple sol-gel reaction in combination with air calcination, and the method is simple and convenient, low in cost, good in repeatability, friendly to the environment, capable of large-scale preparation, and suitable for industrial use. The method of preparing the present invention is simple, providing a new thought for synthesizing a high-activity electrode material.

[0085] (6) In particular, in the sol-gel method of the present invention, a multidentate ligand high-molecular weight polymer coordinates with or binds to metal cations to form a complex. Compared with a small-molecular weight complex, the high-molecular weight polymer multidentate ligand facilitates uniform dispersion of multiple metals in a final product, which may improve the activity and stability of the material.

[0086] (7) In the solvothermal method of the present invention, weak alkali sources such as urea and ammonium hydroxide may be used as the alkali source. Such weak alkali sources may slowly release hydroxyl ions at a high temperature, thereby achieving slow coprecipitation of ruthenium with acid-insoluble metal or metal oxide ions, and preventing phenomena such as metal phase splitting caused by excessively large changes in the pH value in the hydrothermal process.

[0087] The transition metal-doped ruthenium oxide nanometer material of the present invention has the following advantages:

[0088] (1) In the transition metal-doped ruthenium oxide nanometer material of the present invention, the transition metal is doped into the crystals of the ruthenium oxide, while atoms of the transition metal replace atoms of ruthenium in positions in the lattices, and the intrinsic structure of the ruthenium oxide is not broken (that is, the crystal structure of the rutile-phase ruthenium oxide is still maintained substantially perfectly). Meanwhile, the transition metal is highly uniformly dispersed in the material, and no impure-phase transition metal oxide is generated, such that active-site ruthenium is well controlled, and certain stability is also kept during the acidic oxygen evolving reaction.

[0089] (2) The transition metal-doped ruthenium oxide nanometer material of the present invention is uniform in particle size, and its method(s) of synthesis are simple. While the transition metal-doped ruthenium oxide nanometer material further lowers the amount of the precious metal ruthenium used, after doping of the transition metal, Ru-O bond covalency is weakened due to the introduction of the transition metal, the active-site ruthenium is at a lower valence state, and thus the transition metal-doped ruthenium oxide nanometer material exhibits extremely high activity and good stability in the process of acidic water electrolysis oxygen evolution as an anode material.

[0090] In particular, in the material of the present invention, transition metal elements have the advantages that: 1, in an acidic electrolyte solution, the catalysts are not dissolved, thereby demonstrating good stability, and under high current density working conditions, a constant current polarization curve can still be kept stable for a long time; and 2, the Ru-O bond covalency is weakened due to the introduction of the transition metal (e.g., manganese, chromium or tin), and the reasons are as follows: (1) in terms of stability: as for the transition metal elements such as manganese, chromium and tin, in the preparation process, the transition metal is in a high-temperature, high-pressure liquid environment or its highest-valence compounds are adopted as a transition metal source, the transition metal may be in a liquid environment in which it is fully oxidized, its oxides have strong acidic stability, and thus the effect of stably controlling ruthenium active sites can be achieved in the acidic oxygen evolution process, thereby improving the stability of the ruthenium oxide; and

[0091] (2) in terms of activity: the doping of the transition metal in the ruthenium oxide can adjust a d-band center of the ruthenium active sites and lower a surface-adsorbate state of anti-bonds, thereby lowering the free energy in a rate-deciding step, and finally improving the intrinsic activity of the ruthenium oxide. Transition metals that are low in valence state and poor in acidic stability, such as iron, cobalt and nickel, do not have the above-mentioned effects, usually because its low valence state does not match with the tetravalent state of the ruthenium oxide, which causes oxygen defects, and changes its oxygen evolving reaction mechanism into a lattice oxygen oxidation mechanism. Although the activity of catalysts in the acidic oxygen evolving reaction is improved, the stability of the catalysts cannot be maintained due to the oxygen defect(s).

[0092] (3) When the transition metal-doped ruthenium oxide nanometer material of the present invention is used as an acidic water electrolysis oxygen evolution anode material, and the doping amount of the transition metal ranges from 1 at % to 50 at % (at % is an atomic or molar mass fraction percentage of the transition metal, based on a total atomic or molar mass of all metals in the transition metal-doped ruthenium oxide nanometer material), the intrinsic activity is extremely high. Specifically, it can be seen from FIGS. 10, 18, 25, 32 and 33 that the transition metal-doped ruthenium oxide nanometer materials obtained in Examples 1 to 18 have good water electrolysis oxygen evolution performance, and the overpotential at a current density of 10 milliamperes per square centimeter is lower than that of commercial ruthenium dioxide (320 millivolts).

[0093] (4) When the transition metal-doped ruthenium oxide nanometer material of the present invention is used as an acidic water electrolysis oxygen evolution anode material, under a high current density working condition of 200 mA cm−2, a constant current polarization curve may be still kept stable for 80 to 100 hours, which proves that the transition metal-doped ruthenium oxide nanometer material has good acidic oxygen evolving reaction stability.

[0094] (5) One method of preparing the present transition metal-doped ruthenium oxide nanometer material is the hydrothermal method. The hydrothermal method is synthesis by performing a simple reaction in a sealed reactor in combination with air calcination, the cost is low, the method is simple, the repeatability is good, and obtained powder is high in purity, good in dispersity, beneficial for environmental cleaning, and capable of large-scale preparation. The method of preparing the present invention provides a new thought for synthesizing a high-activity electrode material.

[0095] (6) In particular, in the hydrothermal method of the present invention, a high-molecular weight polymer having a multidentate ligand coordinates with or binds to metal cations to form a complex. By adding the high-molecular weight polymer having a plurality of coordinatable groups, particle agglomeration may be avoided. It is beneficial for the transition metal to be uniformly dispersed in rutile lattices of the ruthenium oxide, and thus the activity and stability of the material can be improved.BRIEF DESCRIPTION OF THE DRAWINGS

[0096] FIG. 1 is a scanning electron microscopy (SEM) image of the niobium-doped ruthenium oxide nanometer material in Example 1.

[0097] FIG. 2 is an X-ray diffraction (XRD) spectrum of the niobium-doped ruthenium oxide nanometer material in Example 1.

[0098] FIG. 3 is an element distribution diagram of the niobium-doped ruthenium oxide nanometer material in Example 1.

[0099] FIG. 4 is a scanning electron microscopy (SEM) image of the niobium-doped ruthenium oxide nanometer material in Example 2 of the present invention.

[0100] FIG. 5 is a high-resolution transmission electron microscopy (HRTEM) image of the niobium-doped ruthenium oxide nanometer material in Example 3 of the present invention.

[0101] FIG. 6 is a high-resolution transmission electron microscopy (HRTEM) image of the niobium-doped ruthenium oxide nanometer material in Example 4 of the present invention.

[0102] FIG. 7 is a scanning electron microscopy (SEM) image of the niobium-doped ruthenium oxide nanometer material in Example 5 of the present invention.

[0103] FIG. 8 is a scanning electron microscopy (SEM) image of the niobium-doped ruthenium oxide nanometer material in Example 6 of the present invention.

[0104] FIG. 9 is a scanning electron microscopy (SEM) image of the niobium-doped ruthenium oxide nanometer material in Example 7 of the present invention.

[0105] FIG. 10 is an X-ray diffraction (XRD) spectrum of the niobium-doped ruthenium oxide nanometer material in Example 8 of the present invention.

[0106] FIG. 11 is an X-ray diffraction (XRD) spectrum of the niobium-doped ruthenium oxide nanometer material in Example 9 of the present invention.

[0107] FIG. 12 is an X-ray diffraction (XRD) spectrum of the niobium-doped ruthenium oxide nanometer material in Example 10 of the present invention.

[0108] FIG. 13 is a scanning electron microscopy (SEM) image of the niobium-doped ruthenium oxide nanometer material in Example 11 of the present invention.

[0109] FIG. 14 is an X-ray diffraction (XRD) spectrum of the titanium-doped ruthenium oxide nanometer material in Example 12 of the present invention.

[0110] FIG. 15 is an X-ray diffraction (XRD) spectrum of the zirconium-doped ruthenium oxide nanometer material in Example 13 of the present invention.

[0111] FIG. 16 is an X-ray diffraction (XRD) spectrum of the hafnium-doped ruthenium oxide nanometer material in Example 14 of the present invention.

[0112] FIG. 17 is an X-ray diffraction (XRD) spectrum of the tungsten-doped ruthenium oxide nanometer material in Example 15 of the present invention.

[0113] FIG. 18 is an X-ray diffraction (XRD) spectrum of the molybdenum-doped ruthenium oxide nanometer material in Example 16 of the present invention.

[0114] FIG. 19 is an X-ray diffraction (XRD) spectrum of the tantalum-doped ruthenium oxide nanometer material in Example 16 of the present invention.

[0115] FIG. 20 is a graph of polarization curves from an oxygen evolving reaction using the niobium-doped ruthenium oxide nanometer materials in Examples 1 to 3 of the present invention and commercial ruthenium dioxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the niobium-doped ruthenium oxide material obtained in Example 1, curve B is the polarization curve of the niobium-doped ruthenium oxide material obtained in Example 2, curve C is the polarization curve of the niobium-doped ruthenium oxide material obtained in Example 3, and curve D is the polarization curve of the commercial ruthenium dioxide.

[0116] FIG. 21 is a graph of stability curves of the niobium-doped ruthenium oxide materials obtained in Example 1 and Example 2 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 1 at a 100 milliampere current density, curve B is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 2 at a 100 milliampere current density, curve C is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 1 at a 200 milliampere current density, and curve D is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 2 at a 200 milliampere current density.

[0117] FIG. 22 is a graph of polarization curves obtained by testing the niobium-doped ruthenium oxide nanometer material obtained in Example 5 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution.

[0118] FIG. 23 is a graph of polarization curves obtained by testing the niobium-doped ruthenium oxide material obtained in Example 6 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution.

[0119] FIG. 24 is a graph of polarization curves obtained by testing the niobium-doped ruthenium oxide material obtained in Example 7 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution.

[0120] FIG. 25 is a graph of polarization curves obtained by testing the niobium-doped ruthenium oxide material obtained in Example 8 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution.

[0121] FIG. 26 is a graph of polarization curves obtained by testing the niobium-doped ruthenium oxide material obtained in Example 10 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution.

[0122] FIG. 27 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 5 at a current density of 100 milliampere per square centimeter.

[0123] FIG. 28 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 7 at a current density of 100 milliampere per square centimeter.

[0124] FIG. 29 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 8 at a current density of 100 milliampere per square centimeter.

[0125] FIG. 30 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 10 at a current density of 100 milliampere per square centimeter.

[0126] FIG. 31 is a graph of polarization curves obtained by testing metal-doped ruthenium oxide materials obtained in Examples 12 to 17 in a 0.5 mol / L sulfuric acid solution.

[0127] FIG. 32 is a graph of stability curves obtained from the metal-doped ruthenium oxide materials obtained in Examples 12 to 17 at a current density of 100 milliampere per square centimeter.

[0128] FIG. 33 is a constant current test curve of commercial ruthenium dioxide at a current density of 100 milliampere per square centimeter.

[0129] FIG. 34 is a graph of polarization curves obtained by testing the niobium-doped ruthenium oxide material obtained in Example 1 and the iron-doped ruthenium oxide material obtained in Comparative Example 1 in a 0.5 mol / L sulfuric acid solution, in which curve A is the polarization curve of the iron-doped ruthenium oxide material obtained in Comparative Example 1, and curve B is the polarization curve of the niobium-doped ruthenium oxide material obtained in Example 1.

[0130] FIG. 35 is a stability curve obtained from the iron-doped ruthenium oxide material obtained in Comparative Example 1 at a current density of 100 milliampere per square centimeter.

[0131] FIG. 36 is an XRD spectrum of the three-metal-doped ruthenium oxide nanometer material obtained in Example 18.

[0132] FIG. 37 is an XRD spectrum of the five-metal-doped ruthenium oxide nanometer material obtained in Example 19.

[0133] FIG. 38 is an XRD spectrum of the seven-metal-doped ruthenium oxide nanometer material obtained in Example 20.

[0134] FIG. 39 is a graph of polarization curves obtained by testing the metal-doped ruthenium oxide materials obtained in Examples 18 to 20 in a 0.5 mol / L sulfuric acid solution.

[0135] FIG. 40 is a graph of stability curves obtained from the metal-doped ruthenium oxide materials obtained in Examples 18 to 20 at a current density of 100 milliampere per square centimeter.

[0136] FIG. 41 is an XRD spectrum of the niobium-doped ruthenium oxide nanometer material obtained in Comparative Example 2.

[0137] FIG. 42 is a graph of polarization curves obtained by testing the niobium-doped ruthenium oxide nanometer material obtained in Comparative Example 2 in a 0.5 mol / L sulfuric acid solution.

[0138] FIG. 43 is a stability curve of the niobium-doped ruthenium oxide obtained in Comparative Example 2 at a current density of 100 milliampere per square centimeter.

[0139] FIG. 44 is a scanning electron microscopy (SEM) image of the manganese-doped ruthenium oxide nanometer material in Example 21 of the present invention.

[0140] FIG. 45 is an X-ray diffraction (XRD) spectrum of the manganese-doped ruthenium oxide nanometer material in Example 21 of the present invention.

[0141] FIG. 46 is an element distribution diagram of the manganese-doped ruthenium oxide nanometer material in Example 21 of the present invention.

[0142] FIG. 47 is a scanning electron microscopy (SEM) image of the chromium-doped ruthenium oxide nanometer material in Example 26 of the present invention.

[0143] FIG. 48 is an X-ray diffraction (XRD) spectrum of the chromium-doped ruthenium oxide nanometer material in Example 26 of the present invention.

[0144] FIG. 49 is an element distribution diagram of the chromium-doped ruthenium oxide nanometer material in Example 26 of the present invention.

[0145] FIG. 50 is a scanning electron microscopy (SEM) image of the tin-doped ruthenium oxide nanometer material in Example 27 of the present invention.

[0146] FIG. 51 is an X-ray diffraction (XRD) spectrum of the tin-doped ruthenium oxide nanometer material in Example 27 of the present invention.

[0147] FIG. 52 is an element distribution diagram of the tin-doped ruthenium oxide nanometer material in Example 27 of the present invention.

[0148] FIG. 53 is a polarization curve graph from an oxygen evolving reaction using the manganese-doped ruthenium oxide nanometer materials obtained in Examples 21 to 25 of the present invention and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 21, curve B is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 22, curve C is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 23, curve D is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 24, curve E is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 25, and curve F is the polarization curve of the commercial ruthenium oxide.

[0149] FIG. 54 is a graph of stability curves obtained from the manganese-doped ruthenium oxide materials obtained in Example 21, Example 24 and Example 25 of the present invention at a current density of 100 milliampere per square centimeter.

[0150] FIG. 55 is a graph of stability curves obtained from the manganese-doped ruthenium oxide material obtained in Example 21, Example 24 and Example 25 of the present invention at a current density of 200 milliampere per square centimeter.

[0151] FIG. 56 is a polarization curve graph from an oxygen evolving reaction using the manganese-doped ruthenium oxide nanometer materials obtained in Example 21 and Comparative Example 3 and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 21, curve B is the polarization curve of the manganese-doped ruthenium oxide material obtained in Comparative Example 3, and curve C is the polarization curve of the commercial ruthenium oxide.

[0152] FIG. 57 is a stability curve obtained from the manganese-doped ruthenium oxide material obtained in Comparative Example 3 at a current density of 100 milliampere per square centimeter.

[0153] FIG. 58 is a stability curve obtained from the manganese-doped ruthenium oxide material obtained in Comparative Example 3 at a current density of 200 milliampere per square centimeter.

[0154] FIG. 59 is a polarization curve graph from an oxygen evolving reaction using the manganese-doped ruthenium oxide nanometer materials obtained in Example 21 and Comparative Example 4 and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the manganese-doped ruthenium oxide material obtained in Comparative Example 4, curve B is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 21, and curve C is the polarization curve of the commercial ruthenium oxide.

[0155] FIG. 60 is a stability curve obtained from the manganese-doped ruthenium oxide material obtained in Comparative Example 4 at a current density of 50 milliampere per square centimeter.

[0156] FIG. 61 is a polarization curve graph of from oxygen evolving reaction using the chromium-doped ruthenium oxide nanometer materials obtained in Example 26 and Comparative Example 5 and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the chromium-doped ruthenium oxide material obtained in Comparative Example 5, curve B is the polarization curve of the chromium-doped ruthenium oxide material obtained in Example 26, and curve C is the polarization curve of the commercial ruthenium oxide.

[0157] FIG. 62 is a stability curve obtained from the chromium-doped ruthenium oxide material obtained in Example 26 of the present invention at a current density of 100 milliampere per square centimeter.

[0158] FIG. 63 is a stability curve obtained from the chromium-doped ruthenium oxide material obtained in Example 26 of the present invention at a current density of 200 milliampere per square centimeter.

[0159] FIG. 64 is a stability curve obtained from the chromium-doped ruthenium oxide material obtained in Comparative Example 5 at a current density of 100 milliampere per square centimeter.

[0160] FIG. 65 is a stability curve obtained from the chromium-doped ruthenium oxide material obtained in Comparative Example 5 at a current density of 200 milliampere per square centimeter.

[0161] FIG. 66 is a polarization curve graph from an oxygen evolving reaction using the chromium-doped ruthenium oxide nanometer materials obtained in Example 26 and Comparative Example 6 and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the chromium-doped ruthenium oxide material obtained in Comparative Example 6, curve B is the polarization curve of the chromium-doped ruthenium oxide material obtained in Example 26, and curve C is the polarization curve of the commercial ruthenium oxide.

[0162] FIG. 67 is a stability curve obtained from the chromium-doped ruthenium oxide material obtained in Comparative Example 6 at a current density of 50 milliampere per square centimeter.

[0163] FIG. 68 is a polarization curve graph from an oxygen evolving reaction using the tin-doped ruthenium oxide nanometer materials obtained in Example 27 and Comparative Example 7 and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the tin-doped ruthenium oxide material obtained in Example 27, curve B is the polarization curve of the tin-doped ruthenium oxide material obtained in Comparative Example 7, and curve C is the polarization curve of the commercial ruthenium oxide.

[0164] FIG. 69 is a stability curve obtained from the tin-doped ruthenium oxide material obtained in Example 27 of the present invention at a current density of 100 milliampere per square centimeter.

[0165] FIG. 70 is a stability curve obtained from the tin-doped ruthenium oxide material obtained in Example 27 of the present invention at a current density of 200 milliampere per square centimeter.

[0166] FIG. 71 is a stability curve obtained from the tin-doped ruthenium oxide material obtained in Comparative Example 7 at a current density of 100 milliampere per square centimeter.

[0167] FIG. 72 is a stability curve obtained from the tin-doped ruthenium oxide material obtained in Comparative Example 7 at a current density of 200 milliampere per square centimeter.

[0168] FIG. 73 is a polarization curve graph from an oxygen evolving reaction using the tin-doped ruthenium oxide nanometer materials obtained in Example 27 and Comparative Example 8 and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the tin-doped ruthenium oxide material obtained in Comparative Example 8, curve B is the polarization curve of the tin-doped ruthenium oxide material obtained in Example 27, and curve C is the polarization curve of the commercial ruthenium oxide.

[0169] FIG. 74 is a stability curve obtained from the tin-doped ruthenium oxide material obtained in Comparative Example 8 at a current density of 100 milliampere per square centimeter.

[0170] FIG. 75 is a polarization curve graph from an oxygen evolving reaction using the transition metal-doped ruthenium oxide nanometer materials obtained in Examples 28 to 32 of the present invention and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the germanium-doped ruthenium oxide material obtained in Example 28, curve B is the polarization curve of the indium-doped ruthenium oxide material obtained in Example 29, curve C is the polarization curve of the antimony-doped ruthenium oxide material obtained in Example 30, curve D is the polarization curve of the niobium-doped ruthenium oxide material obtained in Example 31, curve E is the polarization curve of the titanium-doped ruthenium oxide material obtained in Example 32, and curve F is the polarization curve of the commercial ruthenium oxide.

[0171] FIG. 76 is a polarization curve graph from an oxygen evolving reaction using the transition metal-doped ruthenium oxide nanometer materials obtained in Examples 33 to 38 of the present invention and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the zirconium-doped ruthenium oxide material obtained in Example 33, curve B is the polarization curve of the hafnium-doped ruthenium oxide material obtained in Example 34, curve C is the polarization curve of the tungsten-doped ruthenium oxide material obtained in Example 35, curve D is the polarization curve of the molybdenum-doped ruthenium oxide material obtained in Example 36, curve E is the polarization curve of the tantalum-doped ruthenium oxide material obtained in Example 37, curve F is the polarization curve of the platinum-doped ruthenium oxide material obtained in Example 38, and curve G is the polarization curve of the commercial ruthenium oxide.

[0172] FIG. 77 is a graph of stability curves obtained from the transition metal-doped ruthenium oxide nanometer materials obtained in Examples 28 to 32 of the present invention at a current density of 200 milliampere per square centimeter.

[0173] FIG. 78 is a graph of stability curves obtained from the transition metal-doped ruthenium oxide nanometer materials obtained in Examples 33 to 38 of the present invention at a current density of 200 milliampere per square centimeter.

[0174] FIG. 79 is a polarization curve graph from an oxygen evolving reaction using the manganese-doped ruthenium oxide nanometer materials obtained in Examples 39 to 43 of the present invention and commercial ruthenium oxide as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 39, curve B is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 40, curve C is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 41, curve D is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 42, curve E is the polarization curve of the manganese-doped ruthenium oxide material obtained in Example 43, and curve F is the polarization curve of the commercial ruthenium oxide.

[0175] FIG. 80 is a graph of stability curves obtained from the manganese-doped ruthenium oxide nanometer materials obtained in Examples 39 to 43 of the present invention at a current density of 200 milliampere per square centimeter.

[0176] FIG. 81 is a constant current test curve of commercial ruthenium dioxide at a current density of 100 milliampere per square centimeter.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0177] The present invention will be further explained below through examples, but is not limited to the present examples. Experimental methods that do not specify specific conditions in the examples are usually carried out under conventional conditions and / or conditions described in a manual, or according to the conditions recommended by manufacturers. General devices, materials, reagents, etc. used can be obtained through commercial channels unless otherwise stated. Raw materials used in the following examples and comparative examples are all commercially available.

[0178] In the following experiments, the water electrolysis oxygen evolution activity of an acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention is tested using a three-electrode system to obtain polarization curves. The three-electrode system included a reference electrode (a silver / silver chloride electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the acid-insoluble metal oxide-doped ruthenium oxide nanometer material in the examples). When a comparison is made, other specific materials below are used for comparison with the working electrode.

[0179] In the following experiments, the water electrolysis oxygen evolution stability of an acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention is tested using a two-electrode system to obtain stability curves. The two-electrode system included a cathode (a platinum gauze electrode) and an anode (the acid-insoluble metal oxide-doped ruthenium oxide nanometer material in the examples). When a comparison is made, other specific materials below are used for comparison with the anode.Example 1—Sol-Gel Method

[0180] A method of preparing a niobium-doped ruthenium oxide nanometer material included the following steps:

[0181] (1) An ethanol solution of ruthenium chloride and an ethanol solution of niobium chloride were placed in a glass reactor, and in the glass reactor, a concentration of the ruthenium chloride was 0.1 mol / L, and a concentration of the niobium chloride was 0.025 mol / L. The lid of the glass reactor was sealed to prevent hydrolysis of the precursor(s). The sealed glass reactor was irradiated for 3 h with ultrasound to obtain a metal ethanol solution with a uniform color.

[0182] Polyvinylpyrrolidone powder was then added into this solution (the concentration of the polyvinylpyrrolidone was 40 g / L), and sealed ultrasound was applied for 1 h to obtain a mixed solution with a uniform color. Then the glass reactor was placed in a constant temperature oil bath and heated for 12 h at a constant temperature of 70° C. Afterwards, the lid was opened, and the solvent was volatilized to dryness to obtain a metal powder precursor with a uniform color.

[0183] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature of the muffle furnace was raised at a rate of 10° C. / min to 400° C., and natural cooling was performed after temperature preservation of 5 h to obtain a black powder sample. The niobium-doped ruthenium oxide nanometer material was obtained after washing with deionized water and ethanol many times and drying, wherein a doping amount of niobium was 20%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=1 / 5=20%.

[0184] The niobium-doped ruthenium oxide nanometer material was characterized.

[0185] FIG. 1 shows a scanning electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material, and FIG. 2 shows its XRD spectrogram. It can be seen from FIG. 1 that a particle size of the niobium-doped ruthenium oxide nanometer material is small, ranging from 50 nm to 200 nm, and particles are quite uniform and have rough and porous surfaces.

[0186] It can be seen from FIG. 2 that the niobium-doped ruthenium oxide nanometer material exhibits a characteristic peak of rutile-phase ruthenium oxide, and compared to a standard card of the rutile-phase ruthenium oxide, the diffraction peak of the niobium-doped ruthenium oxide moves towards a low angle without a diffraction peak of any niobium oxide, indicating that the niobium is successfully doped into lattices of the ruthenium oxide without producing a split phase. That is, in the niobium-doped ruthenium oxide nanometer material, niobium is doped into the lattices of the ruthenium oxide to replace the ruthenium in lattice positions.

[0187] Therefore, FIG. 2 proves that a molecular formula of the material is NbxRu1-xO2.

[0188] An element distribution diagram of the obtained niobium-doped ruthenium oxide nanometer material is as shown in FIG. 3. It can be seen from FIG. 3 that the niobium-doped ruthenium oxide nanometer material has uniform element distribution, and particularly niobium and ruthenium are consistently distributed on whole particles, indicating that niobium is uniformly dispersed within crystals of the ruthenium oxide. Therefore, niobium and ruthenium are both uniformly dispersed in the niobium-doped ruthenium oxide nanometer material.Example 2—Sol-Gel Method

[0189] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with an ethyl niobate aqueous solution, and polyvinylpyrrolidone was replaced with polyvinyl alcohol. The amounts of ruthenium chloride and ethyl niobate were changed, and in the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 1 mol / L, and the concentration of the ethyl niobate aqueous solution was 0.01 mol / L. Calcination conditions in the muffle furnace were: the temperature was raised at a rate of 10° C. / min to a temperature of 400° C. for 5 hours.

[0190] The doping amount of niobium in the niobium-doped ruthenium oxide nanometer material was 1%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=0.001 / 0.1=1%.

[0191] See FIG. 4 for a scanning electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material.Example 3—Sol-Gel Method

[0192] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with an ethyl niobate aqueous solution, and polyvinylpyrrolidone was replaced with polyethylene glycol. The amounts of ruthenium chloride and ethyl niobate were changed, and in the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 1 mol / L, and the concentration of the ethyl niobate aqueous solution was 1 mol / L. The doping amount of niobium in the niobium-doped ruthenium oxide nanometer material was 50%. Calcination conditions of the muffle furnace were: the temperature raised at a rate was 10°C. / min to a temperature of 400° C. for 5 hours.

[0193] The doping amount of niobium in the niobium-doped ruthenium oxide nanometer material was 50%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=25 / 50=50%.

[0194] See FIG. 5 for a high-resolution transmission electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material. In the figure, 0.317 nm corresponds to a 110 crystal plane of the ruthenium oxide.Example 4—Sol-Gel Method

[0195] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with an ethyl niobate aqueous solution, and polyvinylpyrrolidone was replaced with polyethylene diamine. The amounts of ruthenium chloride and ethyl niobate were changed, and in the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 0.8 mol / L, and the concentration of the ethyl niobate aqueous solution was 0.2 mol / L. Calcination conditions of the muffle furnace were: the temperature raised at a rate was 10° C. / min to a temperature of 400° C., for 5 hours.

[0196] The doping amount of niobium in the niobium-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=2 / 10=20%.

[0197] See FIG. 6 for a high-resolution transmission electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material. In the figure, 0.256 nm and 0.316 nm correspond to the 101 crystal planes and the 110 crystal planes of the ruthenium oxide, respectively, and it can be seen that due to the reduction of the doping amount of niobium, compared to Example 3, a lattice distance in Example 4 is decreased.Example 5—Sol-Gel Method

[0198] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with an aqueous solution of niobium carbonyl, and polyvinylpyrrolidone was replaced with polylactic acid. The amounts of ruthenium chloride and niobium carbonyl were changed, and in the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 0.8 mol / L, and the concentration of the niobium carbonyl aqueous solution was 0.2 mol / L. Calcination conditions of the muffle furnace were: the temperature raised at a rate was 10° C. / min to a temperature of 400° C., for 5 hours.

[0199] The doping amount of niobium in the niobium-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=2 / 10=20%.

[0200] See FIG. 7 for a scanning electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material.Example 6—Sol-Gel Method

[0201] Referring to the method in Example 1, polyvinylpyrrolidone was replaced with polypyridine. The ethanol solution of niobium chloride was replaced with an aqueous ammonium niobium oxalate solution. Ruthenium chloride was replaced with ruthenium acetylacetonate. The amount of ethylene diamine tetraacetic acid was changed to 60 mg, that is, the concentration of the ligand was 1 g / L. Calcination conditions of the muffle furnace were: the temperature raised at a rate was 10° C. / min to a temperature of 500° C., for 6 hours. The doping amount of niobium in the niobium-doped ruthenium oxide nanometer material was 20%.

[0202] See FIG. 8 for a scanning electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material. It can be seen from FIG. 8 that a particle size of the niobium-doped ruthenium oxide nanometer material is small, ranging from 50 nm to 200 nm, and particles are quite uniform and have rough and porous surfaces.Example 7—Sol-Gel Method

[0203] Referring to the method in Example 1, the ethanol solution of niobium chloride was changed to an aqueous niobium oxalate solution, and polyvinylpyrrolidone was changed to a polyamide. Ruthenium chloride was replaced with ruthenium nitrosylnitrate. The doping amount of niobium in the niobium-doped ruthenium oxide nanometer material was 20%.

[0204] See FIG. 9 for a scanning electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material. It can be seen from FIG. 9 that a particle size of the niobium-doped ruthenium oxide nanometer material is small, ranging from 50 nm to 200 nm, and particles are quite uniform and have rough and porous surfaces.Example 8—Solvothermal Method(1) An aqueous solution of ruthenium chloride and niobium oxalate was placed in a 40 ml hydrothermal reactor. Ultrasound was applied for 15 minutes to completely dissolve the precursor(s). The concentration of the ruthenium chloride was 0.1 mol / L, and the concentration of the niobium oxalate was 0.001mol / L. 4 mol / L of urea was added, the hydrothermal reactor was placed in a constant-temperature 100° C. blasting oven for 8 hours, the hydrothermal reactor was taken out, and after natural cooling to room temperature, the sediment generated by the reaction was taken out. After centrifugal washing with deionized water many times, the product was placed into an 80° C. oven to be dried.

[0206] (2) The above dried powder sample was placed into a porcelain boat, and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate of 5° C. / min to 400° C. for 2 h. After natural cooling, a black powder sample (the niobium-doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of niobium was 1%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=1 / 101=1%.

[0207] See FIG. 10 for the XRD spectrum of the obtained niobium-doped ruthenium oxide nanometer material. It can be seen from FIG. 10 that the niobium element is successfully doped into lattices of the ruthenium oxide. That is, in the niobium-doped ruthenium oxide nanometer material, niobium is doped into the lattices of the ruthenium oxide to replace ruthenium atoms in lattice positions. Therefore, FIG. 10 proves that a molecular formula of the material is NbxRu1-xO2.Example 9—Solvothermal Method(1) An aqueous solution of ruthenium chloride and niobium oxalate was placed in a 40 ml hydrothermal reactor. Ultrasound was applied for 15 minutes to completely dissolve the precursor(s). The concentration of the ruthenium chloride was 1 mol / L, and the concentration of the niobium oxalate was 1 mol / L. 0.1 mol / L of ammonium hydroxide was added, the hydrothermal reactor was placed in a constant-temperature 200° C. blasting oven for 16 hours, the hydrothermal reactor was taken out, and after natural cooling to room temperature, the sediment generated by the reaction was taken out, and after centrifugal washing with deionized water many times, the product was placed into an 80° C. oven to be dried.

[0209] (2) The above dried powder sample was placed into a porcelain boat, and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate of 10° C. / min to 600° C. for 8 h. After natural cooling, a black powder sample (the niobium-doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of niobium was 50%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=1 / 2=50%.

[0210] See FIG. 11 for the XRD spectrum of the obtained niobium-doped ruthenium oxide nanometer material. It can be seen from FIG. 11 that the niobium element is successfully doped into lattices of the ruthenium oxide. That is, in the niobium-doped ruthenium oxide nanometer material, niobium is doped into the lattices of the ruthenium oxide to replace a position of ruthenium in part of the lattices. Therefore, FIG. 11 proves that a molecular formula of the material is NbxRu1-xO2.Example 10—Ball Milling Method

[0211] Ruthenium oxide and niobium pentoxide were placed into a 40 ml ball milling tank and mixed evenly. The amount of ruthenium oxide was 9 mol, and the amount of niobium pentoxide was 9 mol. The time of ball milling was 6 hours. The ball milling was repeated twice. The precursor powder sample which was ball-milled uniformly was placed into a porcelain boat, and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate from 5° C. / min to 10° C. / min to a temperature of 800° C. for 6 h. After natural cooling, a black powder sample (the niobium-doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of niobium was 50%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=9 / 18=50%.

[0212] See FIG. 12 for the XRD spectrum of the obtained niobium-doped ruthenium oxide nanometer material, where it can be seen that its crystal structure is still maintained as a crystal structure of the ruthenium oxide. It is expressed as NbxRu1-xO2.Example 11—Ball Milling Method

[0213] Ruthenium oxide and niobium pentoxide were placed into a 40 ml ball milling tank. The amount of ruthenium oxide was 9.9 mol, and the amount of niobium pentoxide was 0.1 mol, time of ball milling was 3 hours each time, and ball milling was repeated 3 times until the precursor(s) were mixed evenly. The above precursor powder sample which was ball-milled uniformly was placed into a porcelain boat and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate from 5° C. / min to 10° C. / min to 400° C. for 12 h.. After natural cooling, a black powder sample (the niobium-doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of niobium was 10%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=0.1 / 10=1%.

[0214] FIG. 13 shows a scanning electron microscopy image of the obtained niobium-doped ruthenium oxide nanometer material. It can be seen that the nanometer material is still porous, and its particle size ranges from 50 nm to 200 nm.Example 12—Titanium-Doped Ruthenium Oxide

[0215] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with a titanium chloride ethanol solution. In the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 1 mol / L, and the concentration of the titanium chloride solution was 0.25 mol / L. Calcination conditions of the muffle furnace were: the temperature was raised at a rate of 10° C. / min to a temperature of 400° C. for 5 hours.

[0216] A doping amount of the titanium in the titanium-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of titanium was N titanium / (N titanium+N ruthenium)=0.25 / 1.25=20%.

[0217] See FIG. 14 for the XRD spectrum of the titanium-doped ruthenium oxide nanometer material obtained in Example 12. It can be seen from FIG. 14 that the titanium element is successfully doped into lattices of the ruthenium oxide. That is, in the titanium-doped ruthenium oxide nanometer material, titanium is doped into the lattices of the ruthenium oxide to replace ruthenium atoms in the lattice positions. Therefore, FIG. 14 proves that a molecular formula of the material is TixRu1-xO2.Example 13—Zirconium-Doped Ruthenium Oxide(1) An aqueous solution of ruthenium chloride and zirconium chloride was placed in a 40 ml hydrothermal reactor. Ultrasound was applied for 15 minutes to completely dissolve the precursor(s). The concentration of the ruthenium chloride was 1 mol / L, and the concentration of the zirconium chloride was 0.25 mol / L. 0.2 g of ammonium hydroxide was added. The hydrothermal reactor was placed in a constant-temperature 200° C. blasting oven for 16 hours. The hydrothermal reactor was taken out, and after natural cooling to room temperature, the sediment generated by the reaction was removed, and after centrifugal washing with deionized water many times, the product was placed into an 80° C. oven to be dried.

[0219] (2) The above dried powder sample was placed into a porcelain boat and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate of 10° C. / min to 600° C. for 8 h. After natural cooling, a black powder sample (the zirconium-doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of zirconium was 20%. A calculation formula of the doping amount of zirconium was N zirconium / (N zirconium+N ruthenium)=0.25 / 1.25=20%.

[0220] See FIG. 15 for the XRD spectrum of the obtained zirconium-doped ruthenium oxide nanometer material. It can be seen from FIG. 15 that the zirconium element is successfully doped into lattices of the ruthenium oxide. That is, in the zirconium-doped ruthenium oxide nanometer material, zirconium is doped into lattices of the ruthenium oxide to replace ruthenium atoms in the lattice positions. Therefore, FIG. 15 proves that a molecular formula of the material is ZrxRu1-xO2.Example 14—Hafnium-Doped Ruthenium Oxide

[0221] Ruthenium oxide and hafnium oxide were placed into a 40 ml ball milling tank and mixed evenly. The amount of ruthenium oxide was 8 mol, and the amount of hafnium oxide was 2 mol. The time of ball milling was 6 hours. The ball milling was repeated twice. The precursor powder sample which was ball-milled uniformly was placed into a porcelain boat, and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate from 5° C. / min to 10° C. / min to 800° C. for 6 h. After natural cooling, a black powder sample (a hafnium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of hafnium was 20%. A calculation formula of the doping amount of hafnium was N hafnium / (N hafnium+N ruthenium)=2 / 10=20%.

[0222] See FIG. 16 for the XRD spectrum of the obtained hafnium-doped ruthenium oxide nanometer material, and it can be seen that its crystal structure is still maintained as a crystal structure of the ruthenium oxide. It is expressed as HfxRu1-xO2.Example 15—Tungsten-Doped Ruthenium Oxide

[0223] Ruthenium oxide and tungsten oxide were placed into a 40 ml ball milling tank and mixed evenly, the amount of ruthenium oxide was 8 mol, and the amount of tungsten oxide was 2 mol. Time of ball milling was 6 hours each time, ball milling was repeated twice, the above precursor powder sample which was ball-milled uniformly was placed into a porcelain boat and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate from 5° C. / min to 10° C. / min to 800° C. for 6 h. After natural cooling, a black powder sample (a tungsten-doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of tungsten was 20%. A calculation formula of the doping amount of tungsten was N tungsten / (N tungsten+N ruthenium)=2 / 10=20%.

[0224] See FIG. 17 for the XRD spectrum of the obtained tungsten-doped ruthenium oxide nanometer material, where it can be seen that its crystal structure is still maintained as a crystal structure of the ruthenium oxide. It is expressed as WxRu1-xO2.Example 16—Molybdenum-Doped Ruthenium Oxide

[0225] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with a molybdenum chloride ethanol solution. In the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 1 mol / L, and the concentration of the molybdenum chloride solution was 0.25 mol / L. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400° C. for 5 hours. A doping amount of molybdenum in the molybdenum-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of molybdenum was N molybdenum / (N molybdenum+N ruthenium)=0.25 / 1.25=20%.

[0226] See FIG. 18 for the XRD spectrum of the obtained molybdenum-doped ruthenium oxide nanometer material. It can be seen from FIG. 18 that the molybdenum is successfully doped into lattices of the ruthenium oxide. That is, in the molybdenum-doped ruthenium oxide nanometer material, molybdenum is doped into the lattices of the ruthenium oxide to replace ruthenium atoms in the lattice positions. Therefore, FIG. 18 proves that a molecular formula of the material is MoxRu1-xO2.Example 17—Tantalum-Doped Ruthenium Oxide

[0227] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with a tantalum chloride ethanol solution. In the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 1 mol / L, and the concentration of the tantalum chloride solution was 0.25 mol / L. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400° C. for 5 hours.

[0228] A doping amount of tantalum in a tantalum-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of tantalum was N tantalum / (N tantalum+N ruthenium)=0.25 / 1.25=20%.

[0229] See FIG. 19 for the XRD spectrum of the obtained tantalum-doped ruthenium oxide nanometer material. It can be seen from FIG. 19 that the tantalum is successfully doped into lattices of the ruthenium oxide. That is, in the tantalum-doped ruthenium oxide nanometer material, tantalum is doped into the lattices of the ruthenium oxide to replace ruthenium atoms in the lattice positions. Therefore, FIG. 19 proves that a molecular formula of the material is TaxRu1-xO2.Application Example 1

[0230] A three-electrode system was used to test water electrolysis oxygen evolution performance of a niobium-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a silver-silver chloride electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the niobium-doped ruthenium oxide nanometer material obtained in Examples 1 to 3 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L sulfuric acid solution, and the polarization curves obtained were as shown in FIG. 20.

[0231] It can be seen from FIG. 20 that the niobium-doped ruthenium oxide nanometer materials obtained in Examples 1 to 3 have good water electrolysis oxygen evolution performance (curves A-C in FIG. 20), which is obviously superior to the commercial ruthenium dioxide material (curve D in FIG. 20), and overpotentials at a current density of 10 milliampere per square centimeter are 196 millivolts, 219 millivolts and 240 millivolts, respectively, which are lower than the 320 millivolts for the commercial ruthenium dioxide.Application Example 2

[0232] FIG. 21 is a graph showing stability curves of the niobium-doped ruthenium oxide materials obtained in Example 1 and Example 2 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution, in which curve A is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 1 at a current density of 100 milliampere per square centimeter, curve B is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 2 at a current density of 100 milliampere per square centimeter, curve C is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 1 at a current density of 200 milliampere per square centimeter, and curve D is the stability curve of the niobium-doped ruthenium oxide material obtained in Example 2 at a current density of 200 milliampere per square centimeter.

[0233] It can be seen from FIG. 21 that, by being kept for 360 hours at current densities of 100 and 200 milliampere per square centimeter, the niobium-doped ruthenium oxide nanometer material obtained in Example 1 and Example 2 barely attenuates in current, indicating that the niobium-doped ruthenium oxide nanometer material has extremely high stability at large current densities when used as an oxygen evolving reaction anode material.Application Example 3

[0234] A three-electrode system was used to test water electrolysis oxygen evolution performance of a niobium-doped ruthenium oxide nanometer material of the present invention. The three-electrode system included a reference electrode (a silver-silver chloride electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the niobium-doped ruthenium oxide nanometer material obtained in Example 5 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L sulfuric acid solution, and the polarization curves obtained were as shown in FIG. 22.

[0235] It can be seen from FIG. 22 that the overpotential of the niobium-doped ruthenium oxide nanometer material prepared in Example 5 at 10 milliampere per square centimeter in an oxygen evolving reaction is 200 millivolts (curve A in FIG. 22), which is obviously lower than the 320 millivolts for the commercial ruthenium dioxide (curve B in FIG. 22), and it proves that the niobium-doped ruthenium oxide obtained in Example 5 has better oxygen evolving reaction activity than the commercial ruthenium dioxide.Application Example 4

[0236] A three-electrode system was used to test water electrolysis oxygen evolving reaction activity of a niobium-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a silver / silver chloride electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the acid-insoluble metal oxide-doped ruthenium oxide nanometer material obtained in Examples 6, 7, 8, 10 or 12 to 17 or commercial ruthenium dioxide).

[0237] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of an acid-insoluble metal oxide-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the acid-insoluble metal oxide-doped ruthenium oxide nanometer material obtained in Examples 6, 7, 8, 10 or 12 to 17 or commercial ruthenium oxide) and a cathode (a platinum gauze electrode).

[0238] FIG. 23 is a graph showing polarization curves obtained by testing the niobium-doped ruthenium oxide nanometer material obtained in Example 6 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 23 that an overpotential of the niobium-doped ruthenium oxide nanometer material prepared in Example 6 at 10 milliampere per square centimeter in an oxygen evolving reaction is 226 millivolts (curve A in FIG. 23), which is lower than the 320 millivolts for the commercial ruthenium dioxide (curve B in FIG. 23), and it proves that the niobium-doped ruthenium oxide prepared in Example 6 has better oxygen evolving reaction activity.

[0239] FIG. 24 is a graph showing polarization curves obtained by testing a niobium-doped ruthenium oxide material obtained in Example 7 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 24 that the overpotential of the niobium-doped ruthenium oxide nanometer material prepared in Example 7 at 10 milliampere per square centimeter in an oxygen evolving reaction is 210 millivolts (a curve A in FIG. 24), which is lower than the 320 millivolts for the commercial ruthenium dioxide (a curve B in FIG. 24), and it proves that the niobium-doped ruthenium oxide prepared in Example 7 has better oxygen evolving reaction activity.

[0240] FIG. 25 is a graph showing polarization curves obtained by testing the niobium-doped ruthenium oxide material obtained in Example 8 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 25 that the overpotential of the niobium-doped ruthenium oxide nanometer material prepared in Example 8 at 10 milliampere per square centimeter in an oxygen evolving reaction is 170 millivolts (curve A in FIG. 25), which is lower than the 320 millivolts for the commercial ruthenium dioxide (curve B in FIG. 25), and it proves that the niobium-doped ruthenium oxide prepared in Example 8 has better oxygen evolving reaction activity.

[0241] FIG. 26 is a graph showing polarization curves obtained by testing the niobium-doped ruthenium oxide material obtained in Example 10 and commercial ruthenium dioxide in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 26 that the overpotential of the niobium-doped ruthenium oxide nanometer material prepared in Example 10 at 10 milliampere per square centimeter in the oxygen evolving reaction is 240 millivolts (curve A in FIG. 26), which is lower than the 320 millivolts for the commercial ruthenium dioxide (curve B in FIG. 26), and it proves that the niobium-doped ruthenium oxide prepared in Example 10 has better oxygen evolving reaction activity.

[0242] FIG. 27 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 5 at a current density of 100 milliampere per square centimeter. It can be seen from FIG. 27 that, by being kept for 100 hours at the current density of 100 milliampere per square centimeter, the niobium-doped ruthenium oxide nanometer material obtained in Example 5 barely attenuates in current, indicating that the niobium-doped ruthenium oxide nanometer material has extremely high stability at a large current density when used as an oxygen evolving reaction anode material.

[0243] FIG. 28 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 7 at a current density of 100 milliampere per square centimeter. It can be seen from FIG. 28 that, by being kept for 25 hours at the current density of 100 milliampere per square centimeter, the niobium-doped ruthenium oxide nanometer material obtained in Example 7 barely attenuates in current, indicating that the niobium-doped ruthenium oxide nanometer material has extremely high stability at a large current density when used as an oxygen evolving reaction anode material.

[0244] FIG. 29 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 8 at a current density of 100 milliampere per square centimeter. It can be seen from FIG. 29 that, by being kept for 45 hours at the current density of 100 milliampere per square centimeter, the niobium-doped ruthenium oxide nanometer material obtained in Example 8 barely attenuates in current, indicating that the niobium-doped ruthenium oxide nanometer material has extremely high stability at a large current density when used as an oxygen evolving reaction anode material.

[0245] FIG. 30 is a stability curve obtained from the niobium-doped ruthenium oxide material obtained in Example 10 at a current density of 100 milliampere per square centimeter. It can be seen from FIG. 30 that, by being kept for 80 hours at the current density of 100 milliampere per square centimeter, the niobium-doped ruthenium oxide nanometer material obtained in Example 10 barely attenuates in current, indicating that the niobium-doped ruthenium oxide nanometer material has extremely high stability at a large current density when used as an oxygen evolving reaction anode material.

[0246] FIG. 31 is a graph showing polarization curves obtained by testing metal-doped ruthenium oxide materials obtained in Examples 12 to 17 in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 31 that, the overpotential of the titanium-doped ruthenium oxide nanometer material prepared in Example 12 at 10 milliampere per square centimeter in the oxygen evolving reaction is 194 millivolts (curve B in FIG. 31), the overpotential of the zirconium-doped ruthenium oxide nanometer material prepared in Example 13 at 10 milliampere per square centimeter in the oxygen evolving reaction is 200 millivolts (curve F in FIG. 31), the overpotential of the hafnium-doped ruthenium oxide nanometer material prepared in Example 14 at 10 milliampere per square centimeter in the oxygen evolving reaction is 210 millivolts (curve C in FIG. 31), the overpotential of the tungsten-doped ruthenium oxide nanometer material prepared in Example 15 at 10 milliampere per square centimeter in the oxygen evolving reaction is 214 millivolts (curve D in FIG. 31), the overpotential of the molybdenum-doped ruthenium oxide nanometer material prepared in Example 16 at 10 milliampere per square centimeter in the oxygen evolving reaction is 194 millivolts (curve A in FIG. 31), and the overpotential of the tantalum-doped ruthenium oxide nanometer material prepared in Example 17 at 10 milliampere per square centimeter in the oxygen evolving reaction is 209 millivolts (curve E in FIG. 31), which are all lower than the 320 millivolts for the commercial ruthenium dioxide (the curve B in FIG. 26), and it proves that the metal-doped ruthenium oxides prepared in Examples 12 to 17 have better oxygen evolving reaction activity.

[0247] FIG. 32 is a graph showing stability curves obtained from the metal-doped ruthenium oxide materials obtained in Examples 12 to 17 at a current density of 100 milliampere per square centimeter. Curve A is a stability curve of the titanium-doped ruthenium oxide prepared in Example 12, curve D is a stability curve of the zirconium-doped ruthenium oxide prepared in Example 13, curve C is a stability curve of the hafnium-doped ruthenium oxide prepared in Example 14, curve F is a stability curve of the tungsten-doped ruthenium oxide prepared in Example 15, curve B is a stability curve of the molybdenum-doped ruthenium oxide prepared in Example 16, and curve E is a stability curve of the tantalum-doped ruthenium oxide prepared in Example 17. It can be seen from FIG. 32 that, by being kept for 60 hours at a current density of 100 milliampere per square centimeter, the metal-doped ruthenium oxide nanometer materials obtained in Examples 12 to 17 barely attenuate in current, indicating that the above metal-doped ruthenium oxide nanometer materials have extremely high stability at a large current density when used as an oxygen evolving reaction anode material.

[0248] FIG. 33 is a constant current test curve of commercial ruthenium dioxide at a current density of 100 milliampere per square centimeter. The current is attenuated by 500 millivolts or more after 1 hour of testing.

[0249] FIG. 19 to FIG. 33 show that the metal-doped ruthenium oxide nanometer materials of the present invention have excellent activity and stability during water electrolysis oxygen evolution, and both are superior to commercial ruthenium dioxide material.

[0250] The above results sufficiently prove that niobium and other transition metals may be doped into ruthenium oxide lattices through a simple method. The niobium-and other transition metal-doped ruthenium oxide nanometer materials have rough surface structures and excellent electrochemical oxygen evolving reaction performance.Comparative Example 1

[0251] In order to highlight the stability of an acid-insoluble metal oxide-doped catalyst, referring to the preparation method in Example 1, niobium chloride was changed to iron chloride (iron oxides generally being soluble in dilute aqueous mineral acids), and an iron-doped ruthenium oxide nanometer material was prepared.

[0252] The iron-doped ruthenium oxide nanometer material was tested as an oxygen evolving reaction anode material, and its polarization curve and stability curve were obtained, as shown in FIG. 34 and FIG. 35.

[0253] As shown in FIG. 34, curve A is an oxygen evolving reaction polarization curve of the iron-doped ruthenium oxide nanometer material obtained in Comparative Example 1, and curve B is an oxygen evolving reaction polarization curve of the niobium-doped ruthenium oxide nanometer material obtained in Example 1. It can be seen from FIG. 34 that the overpotential of the niobium-doped ruthenium oxide at 10 milliampere per square centimeter is 196 millivolts, while the overpotential of the iron-doped ruthenium oxide is 320 millivolts. Therefore, the niobium-doped ruthenium oxide has higher oxygen evolving reaction activity.

[0254] FIG. 35 is a stability curve of the iron-doped ruthenium oxide obtained in Comparative Example 1 at a current density of 100 milliampere per square centimeter. It can be seen from FIG. 35 that, after 1 hour, the stability curve is attenuated by 300 millivolts or more, and the stability of the iron-doped ruthenium oxide nanometer material is poor. Therefore, there is a significant difference in stability between the iron-doped ruthenium oxide nanometer material in Comparative Example 1 and the niobium-doped ruthenium oxide obtained in Example 1, which further indicates that the niobium-doped ruthenium oxide has extremely good stability in oxygen evolving reactions.Example 18—Three-Metal-Doped Ruthenium Oxide

[0255] Referring to the method in Example 1, the ethanol solution of niobium chloride was replaced with a molybdenum chloride, titanium chloride and niobium chloride ethanol solution. In the glass reactor, the concentration of the ethanol solution of ruthenium chloride was 1 mol / L, and a total concentration of the molybdenum chloride, titanium chloride and niobium chloride was 0.25 mol / L (specifically: molybdenum chloride, titanium chloride and niobium chloride were each present in a concentration of 0.083 mol / L). Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400° C. for 5 hours.

[0256] The doping amount of molybdenum, titanium and niobium in the doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of molybdenum, titanium and niobium was (N molybdenum+N titanium+N niobium) / (N molybdenum+N titanium+N niobium+N ruthenium)=0.25 / 1.25=20%.

[0257] See FIG. 36 for the XRD spectrum of the obtained three-metal-doped ruthenium oxide nanometer material. It can be seen from FIG. 36 that the three elements of molybdenum, titanium and niobium are successfully doped into lattices of the ruthenium oxide. That is, in the molybdenum-doped ruthenium oxide nanometer material, molybdenum, titanium and niobium are doped into the lattices of the ruthenium oxide to replace ruthenium atoms in the lattice positions. Therefore, FIG. 36 proves that a molecular formula of the material is (TiNbMo)xRu1-xO2.Example 19—Five-Metal-Doped Ruthenium Oxide(1) An aqueous solution of ruthenium chloride, zirconium chloride, niobium chloride, titanium chloride, molybdenum chloride and tungsten chloride was placed in a 40 ml glass hydrothermal reactor. Ultrasound was applied for 15 minutes to completely dissolve the precursor(s). The concentration of the ruthenium chloride was 1 mol / L, and a total concentration of the zirconium chloride, the niobium chloride, the titanium chloride, the molybdenum chloride and the tungsten chloride was 0.25 mol / L (specifically: the zirconium chloride, the niobium chloride, the titanium chloride, the molybdenum chloride and the tungsten chloride were each present in a concentration of 0.05 mol / L). 0.2 g of ammonium hydroxide was added, the hydrothermal reactor was placed in a constant-temperature 200° C. blasting oven for 16 hours, the hydrothermal reactor was taken out, and after natural cooling to room temperature, the sediment generated by the reaction was removed. After centrifugal washing with deionized water many times, the product was placed into an 80° C. oven to be dried.

[0259] (2) The above dried powder sample was placed into a porcelain boat, and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate of 10° C. / min to 600° C. for 8 h. After natural cooling, a black powder sample (the doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of metal was 20%. A calculation formula of the doping amount of zirconium, niobium, titanium, molybdenum and tungsten was (N zirconium+N niobium+N titanium+N molybdenum+N tungsten) / (N zirconium+N niobium+N titanium+N molybdenum+N tungsten+N ruthenium)=0.25 / 1.25=20%.

[0260] See FIG. 37 for the XRD spectrum of the obtained five-metal-doped ruthenium oxide nanometer material. It can be seen from FIG. 37 that the five elements are successfully doped into lattices of the ruthenium oxide. That is, in the five-metal-doped ruthenium oxide nanometer material, the five metals are doped into the lattices of the ruthenium oxide to replace ruthenium atoms in the lattice positions. Therefore, FIG. 37 proves that a molecular formula of the material is (NbZrTiMoW)xRu1-xO2.Example 20—Seven-Metal-Doped Ruthenium Oxide

[0261] Ruthenium oxide, titanium oxide, niobium oxide, tantalum oxide, zirconium oxide, hafnium oxide, molybdenum oxide and tungsten oxide were placed in a 40 ml ball milling tank and mixed evenly. The amount of ruthenium oxide was 8 mol, and the amounts of titanium oxide, niobium oxide, tantalum oxide, zirconium oxide, hafnium oxide, molybdenum oxide and tungsten oxide were 2 mol in total (specifically: the amounts of titanium oxide, niobium oxide, tantalum oxide, zirconium oxide, hafnium oxide, molybdenum oxide and tungsten oxide were all 0.0355 mol each). The time of ball milling was 6 hours. The ball milling was repeated twice. The precursor powder sample which was ball-milled uniformly was placed into a porcelain boat, and the porcelain boat was placed into a muffle furnace. The temperature was raised at a rate from 5° C. / min to 10° C. / min to 800° C. for 6 h. After natural cooling, a black powder sample (the doped ruthenium oxide nanometer material) was obtained, wherein a doping amount of titanium, niobium, tantalum, zirconium, hafnium, molybdenum and tungsten was 20%. A calculation formula of the doping amount of titanium, niobium, tantalum, zirconium, hafnium, molybdenum and tungsten was (N zirconium+N niobium+N titanium+N molybdenum+N tungsten+N hafnium+N tantalum) / (N zirconium+N niobium+N titanium+N molybdenum+N tungsten+N hafnium+N tantalum+N ruthenium)=2 / 10=20%.

[0262] See FIG. 38 for the XRD spectrum of the obtained seven-metal-doped ruthenium oxide nanometer material, where it can be seen that its crystal structure is still maintained as a crystal structure of the ruthenium oxide. It is expressed as (TiHfZrNbTaWMo)xRu1-xO2.

[0263] Refer to Examples 18, 19 or 20 for preparation of other two-metal, four-metal or six-metal-doped ruthenium oxide nanometer materials.Application Example 5

[0264] FIG. 39 is a graph showing polarization curves obtained by testing metal-doped ruthenium oxide materials obtained in Examples 18 to 20 in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 39 that the overpotential of the three-metal-doped ruthenium oxide nanometer material prepared in Example 18 at 10 milliampere per square centimeter in an oxygen evolving reaction is 242 millivolts (curve A in FIG. 39), the overpotential of the five-metal-doped ruthenium oxide nanometer material prepared in Example 19 at 10 milliampere per square centimeter in an oxygen evolving reaction is 231 millivolts (curve B in FIG. 39), and the overpotential of the seven-metal-doped ruthenium oxide nanometer material prepared in Example 20 at 10 milliampere per square centimeter in an oxygen evolving reaction is 235 millivolts (curve C in FIG. 39), which are all lower than the 320 millivolts for the commercial ruthenium dioxide (curve D in FIG. 39), and it proves that the metal-doped ruthenium oxides prepared in Examples 18 to 20 have better oxygen evolving reaction activity.Application Example 6

[0265] FIG. 40 is a graph showing stability curves obtained from the metal-doped ruthenium oxide materials obtained in Examples 18 to 20 at a current density of 100 milliampere per square centimeter. Curve A is the stability curve of the molybdenum-titanium-niobium doped ruthenium oxide prepared in Example 18, curve B is the stability curve of the zirconium-tungsten-molybdenum-titanium-niobium doped ruthenium oxide prepared in Example 19, and curve C is the stability curve of the molybdenum-titanium-niobium-zirconium-hafnium-tantalum-tungsten doped ruthenium oxide prepared in Example 20. It can be seen from FIG. 40 that, by being kept for 50 hours at the current density of 100 milliampere per square centimeter, the metal-doped ruthenium oxide nanometer materials obtained in Examples 18 to 20 barely attenuate in current, indicating that the above metal-doped ruthenium oxide nanometer materials have extremely high stability at a large current density when used as an oxygen evolving reaction anode material.Comparative Example 2

[0266] In order to highlight the role of a high-molecular weight polymer multidentate ligand in synthesis of an acid-insoluble metal oxide-doped ruthenium oxide nanometer material, referring to the preparation method in Example 1, polyvinylpyrrolidone was replaced with citric acid, and a niobium-doped ruthenium oxide nanometer material was prepared. See FIG. 41 for the XRD spectrum of the obtained niobium-doped ruthenium oxide nanometer material. It can be seen from FIG. 41 that the niobium element is successfully doped into lattices of the ruthenium oxide. That is, in the niobium-doped ruthenium oxide nanometer material, niobium is doped into the lattices of the ruthenium oxide to replace ruthenium atoms in the lattice positions. Therefore, FIG. 41 proves that a molecular formula of the material is (Nb)xRu1-xO2.

[0267] The niobium-doped ruthenium oxide nanometer material prepared in Comparative Example 2 was tested as an oxygen evolving reaction anode material in a 0.5 mol / L sulfuric acid solution, and its polarization curve and stability curve were obtained, as shown in FIG. 42 and FIG. 43.

[0268] As shown in FIG. 42, curve A is an oxygen evolving reaction polarization curve of the niobium-doped ruthenium oxide nanometer material obtained in Comparative Example 2, and curve B is an oxygen evolving reaction polarization curve of the niobium-doped ruthenium oxide nanometer material obtained in Example 1. It can be seen from FIG. 42 that the overpotential of the niobium-doped ruthenium oxide obtained in Example 1 at 10 milliampere per square centimeter is 196 millivolts, while the overpotential of the niobium-doped ruthenium oxide obtained in Comparative Example 2 is 228 millivolts. Therefore, the niobium-doped ruthenium oxide obtained from the high-molecular weight polymer multidentate ligand has higher oxygen evolving reaction activity.

[0269] FIG. 43 is a stability curve of the niobium-doped ruthenium oxide obtained in Comparative Example 2 at a current density of 100 milliampere per square centimeter. It can be seen from FIG. 43 that, after 80 hours, the stability curve is attenuated by 100 millivolts or more. The comparison between FIG. 43 and FIG. 21 proves that the oxygen evolving reaction stability of the niobium-doped ruthenium oxide nanometer material obtained with the citric acid as a ligand is lower than the stability of the niobium-doped ruthenium oxide nanometer material obtained with polyvinylpyrrolidone as a ligand. Therefore, there is a significant difference in stability between the niobium-doped ruthenium oxide nanometer material in Comparative Example 2 and the niobium-doped ruthenium oxide obtained in Example 1. This further indicates that, the acid-insoluble metal oxide-and transition metal-doped ruthenium oxide nanometer materials prepared using a high-molecular weight polymer multidentate ligand are extremely good in oxygen evolving reaction stability.

[0270] In the following experiments, the water electrolysis oxygen evolution activity of a transition metal-doped ruthenium oxide nanometer material of the present invention is tested using a three-electrode system to obtain polarization curves. Three-electrode system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the transition metal-doped ruthenium oxide nanometer material obtained in the examples). When a comparison is made, other specific materials below are used for comparison with the working electrode.

[0271] In the following experiments, the water electrolysis oxygen evolution stability of transition metal-doped ruthenium oxide nanometer materials of the present invention is also tested using a two-electrode system to obtain stability curves. The two-electrode system includes a cathode (a platinum gauze electrode) and an anode (the transition metal-doped ruthenium oxide nanometer material obtained in the examples). When a comparison is made, other specific materials below are used for comparison with the anode.Example 21—Hydrothermal Method

[0272] A method of preparing a manganese-doped ruthenium oxide nanometer material included the following steps:

[0273] (1) An aqueous ruthenium chloride solution was placed in a beaker, and then a potassium permanganate solution and a manganese chloride tetrahydrate solution which were made uniform by ultrasound were added in sequence, such that divalent manganese ions were in a liquid environment with fully-oxidized metal (e.g., the ruthenium). All reaction liquids were added and then fully stirred for 0.5 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of manganese chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a manganese-ruthenium oxide solution with a uniform color.

[0274] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, naturally cooled to room temperature, and the reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times. The resulting product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0275] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the manganese-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of manganese was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=0.1 / 0.5=20%. The manganese-doped ruthenium oxide nanometer material was characterized.

[0276] FIG. 44 is a scanning electron microscopy image of the obtained manganese-doped ruthenium oxide nanometer material, and FIG. 45 is its XRD spectrogram. It can be seen from FIG. 44 that the manganese-doped ruthenium oxide nanometer material comprises spherical particles with a size ranging from 70 nm to 200 nm, and the surface is rough.

[0277] See FIG. 45 for the XRD spectrogram of the obtained manganese-doped ruthenium oxide nanometer material. It can be seen from FIG. 45 that the manganese-doped ruthenium oxide nanometer material exhibits a characteristic peak of rutile-phase ruthenium oxide, and compared to a standard card of the rutile-phase ruthenium oxide, a diffraction peak of a manganese-doped ruthenium oxide moves towards a high angle without a diffraction peak of any manganese oxide, indicating that the manganese is successfully doped into crystals of the ruthenium oxide without producing a split phase. That is, in the manganese-doped ruthenium oxide nanometer material, manganese is doped into the crystals of the ruthenium oxide to replace ruthenium atoms in the lattice positions.

[0278] Therefore, FIG. 45 proves that a molecular formula of the material is MnxRu1-xO2.

[0279] An element distribution diagram of the obtained manganese-doped ruthenium oxide nanometer material is as shown in FIG. 46. It can be seen from FIG. 46 that the manganese-doped ruthenium oxide nanometer material has uniform element distribution, indicating that manganese is uniformly dispersed within the crystals of the ruthenium oxide. Therefore, manganese and ruthenium are both uniformly dispersed in the manganese-doped ruthenium oxide nanometer material.Example 22—Hydrothermal Method

[0280] Referring to the method in Example 21, polyvinylpyrrolidone was replaced with polyvinyl alcohol. In the beaker, the concentration of the ruthenium chloride solution was 1 mol / L, the concentration of the manganese chloride solution was 0.01 mol / L, and the concentration of the polyvinyl alcohol in the beaker was 50 g / L. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400° C. for 3 h.

[0281] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 1%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=0.01 / (1+0.01)=1%.Example 23—Hydrothermal Method

[0282] Referring to the method in Example 21, polyvinylpyrrolidone was replaced with polyethylene diamine. In the beaker, the concentration of the ruthenium chloride solution was 1 mol / L, the concentration of the manganese chloride solution was 1 mol / L, and the concentration of the polyethylene diamine in the beaker was 50 g / L. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400° C. for 3 h.

[0283] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 50%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=1 / (1+1)=50%.Example 24—Hydrothermal Method

[0284] Referring to the method in Example 21, in the beaker, the concentration of the ruthenium chloride solution was 0.4 mol / L, the concentration of the manganese chloride solution was 0.1 mol / L, and the concentration of the polyvinylpyrrolidone in the beaker was 1 g / L. Calcination conditions of the muffle furnace were: the temperature was raised at a rate of 10° C. / min to a temperature of 400° C. for 3 h.

[0285] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=0.1 / (0.4+0.1)=20%.Example 25—Hydrothermal Method

[0286] Referring to the method in Example 1, polyvinylpyrrolidone was replaced with polylactic acid. In the beaker, the concentration of the ruthenium chloride solution was 0.4 mol / L, the concentration of the manganese chloride solution was 0.1 mol / L, and the concentration of the polylactic acid in the beaker was 1 g / L. Calcination conditions of the muffle furnace were: the temperature was raised at a rate of 10° C. / min to a temperature of 400° C. for 3 h.

[0287] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=0.1 / (0.4+0.1)=20%.Comparative Example 3—Hydrothermal Method

[0288] Those skilled in the art generally considered that the existence of a ligand could promote doping of the transition metal manganese into lattices of ruthenium oxide and improve the stability of the catalyst at the same time.

[0289] This comparative example took the ligand ammonium citrate as an example for performing the following experiment.

[0290] Referring to the preparation method in Example 21, the difference with Example 21 was only in that the polyvinylpyrrolidone was replaced with ammonium citrate, i.e. before the reaction liquid was transferred into the hydrothermal reactor, ammonium citrate was added into the reaction liquid, and the concentration of the ammonium citrate was 50 g / L. Ammonium hydroxide was then added to adjust pH to be neutral. In a stirring process, the ammonium citrate solution was mixed with the reaction liquid, and after full stirring, the manganese-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of manganese was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=0.1 / 0.5=20%.Comparative Example 4—Hydrothermal method

[0291] This comparative example took manganese chloride tetrahydrate and potassium permanganate as an example for performing the following experiment.

[0292] Referring to the preparation method in Example 21, the difference with Example 21 was only in that polyvinylpyrrolidone was not added, and after full stirring and a reaction, the manganese-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of manganese was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=1 / 5=20%.Example 26—Hydrothermal Method

[0293] A method of preparing a chromium-doped ruthenium oxide nanometer material included the following steps.

[0294] (1) An aqueous ruthenium chloride solution was placed in a beaker, and then a potassium dichromate solution and a chromium chloride solution which were made uniform by ultrasound were added in sequence, such that trivalent chromium ions were located in a liquid environment with fully-oxidized metal (e.g., the ruthenium). All reaction liquids were added and then fully stirred for 0.5 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of chromium chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a chromium-ruthenium oxide solution with a uniform color.

[0295] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, naturally cooled to the room temperature, and the reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times. Then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0296] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the chromium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of chromium was 20%. A calculation formula of the doping amount of chromium was N chromium / (N chromium+N ruthenium)=0.1 / 0.5=20%.

[0297] The chromium-doped ruthenium oxide nanometer material was characterized.

[0298] See FIG. 47 for a scanning electron microscopy image of the obtained chromium-doped ruthenium oxide nanometer material, and see FIG. 48 for its XRD spectrogram. It can be seen from FIG. 47 that the chromium-doped ruthenium oxide nanometer material is spherical particles with a size ranging from 70 nm to 200 nm, and the surface is relatively rough.

[0299] See FIG. 48 for the XRD spectrogram of the obtained chromium-doped ruthenium oxide nanometer material. It can be seen from FIG. 48 that the chromium-doped ruthenium oxide nanometer material exhibits a characteristic peak of rutile-phase ruthenium oxide, and compared to a standard card of the rutile-phase ruthenium oxide, a diffraction peak of the chromium-doped ruthenium oxide moves towards a high angle without a diffraction peak of any chromium oxide, indicating that the chromium is successfully doped into crystals of the ruthenium oxide without producing a split phase. That is, in the chromium-doped ruthenium oxide nanometer material, chromium is doped into the crystals of the ruthenium oxide to replace ruthenium atoms in the lattice positions.

[0300] Therefore, FIG. 48 proves that a molecular formula of the material is CrxRu1-xO2.

[0301] An element distribution diagram of the obtained chromium-doped ruthenium oxide nanometer material is shown in FIG. 49. It can be seen from FIG. 49 that the chromium-doped ruthenium oxide nanometer material has uniform element distribution, indicating that chromium is uniformly dispersed within the crystals of the ruthenium oxide. Therefore, chromium and ruthenium are both uniformly dispersed in the chromium-doped ruthenium oxide nanometer material.Comparative Example 5—Hydrothermal Method

[0302] Those skilled in the art generally considered that the existence of a ligand could promote doping of transition metal chromium into crystals of ruthenium oxide and improve the stability of the catalyst at the same time.

[0303] This comparative example took the ligand ammonium citrate as an example for performing the following experiment.

[0304] Referring to the preparation method in Example 26, the difference with Example 26 was only in that the polyvinylpyrrolidone was replaced with ammonium citrate, i.e. before the reaction liquid was transferred into the hydrothermal reactor, ammonium citrate was added into the reaction liquid. The concentration of the ammonium citrate was 50 g / L. Ammonium hydroxide was then added to adjust pH to be neutral. In the stirring process, the ammonium citrate solution was mixed with the reaction liquid, and after full stirring, the chromium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of chromium was 20%. A calculation formula of the doping amount of chromium was N chromium / (N chromium+N ruthenium)=1 / 5=20%.Comparative Example 6—Hydrothermal Method

[0305] This comparative example took chromium chloride and potassium dichromate as an example for performing the following experiment.

[0306] Referring to the preparation method in Example 26, the difference with Example 26 was only in that polyvinylpyrrolidone was not added, and after full stirring and reaction, the chromium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of chromium was 20%. A calculation formula of the doping amount of chromium was N chromium / (N chromium+N ruthenium)=1 / 5=20%.Example 27—Hydrothermal Method

[0307] A method of preparing a tin-doped ruthenium oxide nanometer material included the following steps.

[0308] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a tin tetrachloride pentahydrate solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was irradiated with sufficient ultrasound for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of tin chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a tin-ruthenium oxide solution with a uniform color.

[0309] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, naturally cooled to room temperature, and the reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0310] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h, and after natural cooling, the tin-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of tin was 20%. A calculation formula of the doping amount of tin was N tin / (N tin+N ruthenium)=0.1 / 0.5=20%.

[0311] The tin-doped ruthenium oxide nanometer material was characterized.

[0312] See FIG. 50 for a scanning electron microscopy image of the obtained tin-doped ruthenium oxide nanometer material, and see FIG. 51 for its XRD spectrogram. It can be seen from FIG. 51 that the tin-doped ruthenium oxide nanometer material comprises spherical particles with a size ranging from 70 nm to 200 nm, and the surface is rough.

[0313] It can be seen from FIG. 51 that the tin-doped ruthenium oxide nanometer material exhibits a characteristic peak of rutile-phase ruthenium oxide, and compared to a standard card of the rutile-phase ruthenium oxide, a diffraction peak of the tin-doped ruthenium oxide moves towards a high angle without a diffraction peak of any tin oxide, indicating that the tin element is successfully doped into crystals of the ruthenium oxide without producing a split phase. That is, in the tin-doped ruthenium oxide nanometer material, tin is doped into the crystals of the ruthenium oxide to replace ruthenium atoms in the lattice positions.

[0314] Therefore, FIG. 51 proves that a molecular formula of the material is SnxRu1-xO2.

[0315] An element distribution diagram of the obtained tin-doped ruthenium oxide nanometer material is as shown in FIG. 52. It can be seen from FIG. 52 that the tin-doped ruthenium oxide nanometer material has uniform element distribution, indicating that tin is uniformly dispersed within the crystals of the ruthenium oxide. Therefore, tin and ruthenium are both uniformly dispersed in the tin-doped ruthenium oxide nanometer material.Comparative Example 7—Hydrothermal Method

[0316] Those skilled in the art generally considered that the existence of a ligand could promote doping of transition metal tin into crystals of ruthenium oxide and improve the stability of the catalyst at the same time.

[0317] This comparative example took a ligand ammonium citrate as an example for performing the following experiment.

[0318] Referring to the preparation method in Example 27, the difference with Example 27 was only in that the polyvinylpyrrolidone was replaced with ammonium citrate, i.e. before the reaction liquid was transferred into the hydrothermal reactor, ammonium citrate was added into the reaction liquid, and the concentration of the ammonium citrate was 50 g / L. Ammonium hydroxide was then added to adjust pH to be neutral. In the stirring process, the ammonium citrate solution was mixed with the reaction liquid, and after full stirring, the tin-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of tin was 20%. A calculation formula of the doping amount of tin was N tin / (N tin+N ruthenium)=1 / 5=20%.Comparative Example 8—Hydrothermal Method

[0319] This comparative example took tin tetrachloride pentahydrate as an example for performing the following experiment.

[0320] Referring to the preparation method in Example 27, the difference with Example 27 was only in that polyvinylpyrrolidone was not added, and after full stirring and a reaction, the tin-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of tin was 20%. A calculation formula of the doping amount of tin was N tin / (N tin+N ruthenium)=1 / 5=20%.Example 28—Germanium-Doped Ruthenium Oxide

[0321] A method of preparing a germanium-doped ruthenium oxide nanometer material included the following steps.

[0322] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a germanium tetrachloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, mechanical stirring was performed for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of germanium chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a germanium-ruthenium oxide solution with a uniform color.

[0323] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0324] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace; and a temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the germanium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of germanium was 20%. A calculation formula of the doping amount of germanium was N germanium / (N germanium+N ruthenium)=0.1 / 0.5=20%.Example 29—Indium-Doped Ruthenium Oxide

[0325] A method of preparing an indium-doped ruthenium oxide nanometer material included the following steps

[0326] (1) An aqueous ruthenium chloride solution was placed in a beaker, then an indium chloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, mechanical stirring was performed for 0.5 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of indium chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain an indium-ruthenium oxide solution with a uniform color.

[0327] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to for 10 h at a constant temperature of 180° C. The hydrothermal reactor was taken out, and naturally cooled to room temperature. the reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0328] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace; and a temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the indium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of indium was 20%. A calculation formula of the doping amount of indium was N indium / (N indium+N ruthenium)=0.1 / (0.1+0.4)=20%.Example 30—Antimony-Doped Ruthenium Oxide

[0329] A method of preparing an antimony-doped ruthenium oxide nanometer material included the following steps:

[0330] (1) An aqueous ruthenium chloride solution was placed in a beaker, then an antimony trichloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasound for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of antimony chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain an antimony-ruthenium oxide solution with a uniform color.

[0331] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0332] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the antimony-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of antimony was 20%. A calculation formula of the doping amount of antimony was N antimony / (N antimony+N ruthenium)=0.1 / (0.1+0.4)=20%.Example 31—Niobium-Doped Ruthenium Oxide

[0333] A method of preparing a niobium-doped ruthenium oxide nanometer material included the following steps.

[0334] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a niobium pentachloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasound for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of niobium chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a niobium-ruthenium oxide solution with a uniform color.

[0335] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0336] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the niobium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of niobium was 20%. A calculation formula of the doping amount of niobium was N niobium / (N niobium+N ruthenium)=0.1 / (0.1+0.4)=20%.Example 32—Titanium-Doped Ruthenium Oxide

[0337] A method of preparing a titanium-doped ruthenium oxide nanometer material included the following steps.

[0338] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a titanium chloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasound for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of titanium chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a titanium-ruthenium oxide solution with a uniform color.

[0339] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0340] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After, the titanium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of titanium was 20%. A calculation formula of the doping amount of titanium was N titanium / (N titanium+N ruthenium)=0.1 / (0.1+0.4)=20%.Example 33—Zirconium-Doped Ruthenium Oxide

[0341] A method of preparing a zirconium-doped ruthenium oxide nanometer material included the following steps.

[0342] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a zirconium chloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasound for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of zirconium chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a zirconium-ruthenium oxide solution with a uniform color.

[0343] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0344] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the zirconium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of zirconium was 20%. A calculation formula of the doping amount of zirconium was N zirconium / (N zirconium+N ruthenium)=0.1 / (0.1+0.4)=20%.Example 34—Hafnium-Doped Ruthenium Oxide

[0345] A method of preparing a hafnium-doped ruthenium oxide nanometer material included the following steps.

[0346] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a hafnium oxide solution which was made uniform by ultrasound was added, and after all reaction liquids were added, mechanical stirring was performed for 0.5 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of hafnium oxide was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a hafnium-ruthenium oxide solution with a uniform color.

[0347] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0348] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the hafnium-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of hafnium was 20%. A calculation formula of the doping amount of hafnium was N hafnium / (N hafnium+N ruthenium)=0.1 / (0.1+0.4)=20%.Example 35—Tungsten-Doped Ruthenium Oxide

[0349] A method of preparing a tungsten-doped ruthenium oxide nanometer material included the following steps.

[0350] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a tungsten oxide solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasonic radiation for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of tungsten oxide was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution., The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a tungsten-ruthenium oxide solution with a uniform color.

[0351] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0352] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the tungsten-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of tungsten was 20%. A calculation formula of the doping amount of tungsten was N tungsten / (N tungsten+N ruthenium)=20%.Example 36—Molybdenum-Doped Ruthenium Oxide

[0353] A method of preparing a molybdenum-doped ruthenium oxide nanometer material included the following steps.

[0354] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a molybdenum chloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasonic radiation for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of molybdenum chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a molybdenum-ruthenium oxide solution with a uniform color.

[0355] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0356] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the molybdenum-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of molybdenum was 20%. A calculation formula of the doping amount of molybdenum was N molybdenum / (N molybdenum+N ruthenium)=20%.Example 37—Tantalum-Doped Ruthenium Oxide

[0357] A method of preparing a tantalum-doped ruthenium oxide nanometer material included the following steps.

[0358] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a tantalum pentachloride solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasonic radiation for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of tantalum chloride was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a tantalum-ruthenium oxide solution with a uniform color.

[0359] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0360] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the tantalum-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of tantalum was 20%. A calculation formula of the doping amount of tantalum was N tantalum / (N tantalum+N ruthenium)=20%.Example 38—Platinum-Doped Ruthenium Oxide

[0361] A method of preparing a platinum-doped ruthenium oxide nanometer material included the following steps.

[0362] (1) An aqueous ruthenium chloride solution was placed in a beaker, then a chloroplatinic acid solution which was made uniform by ultrasound was added, and after all reaction liquids were added, the beaker was subjected to sufficient ultrasonic radiation for 1 h. In the beaker, the concentration of ruthenium chloride was 0.4 mol / L, and the concentration of chloroplatinic acid was 0.1 mol / L. Polyvinylpyrrolidone powder was then added into this solution. The concentration of polyvinylpyrrolidone in the beaker was 50 g / L, and stirring was continued for 1 h to obtain a platinum-ruthenium oxide solution with a uniform color.

[0363] The reaction liquid in the beaker was then transferred into a hydrothermal reactor, and the hydrothermal reactor was placed in a blasting oven and subjected to a constant temperature of 180° C. for 10 h. The hydrothermal reactor was taken out, and naturally cooled to room temperature. The reaction liquid in the reactor was centrifuged to separate a solid product, which was washed alternately with deionized water and anhydrous ethanol many times, and then the product was placed in an 80° C. oven to be dried to obtain a metal powder precursor with a uniform color.

[0364] (2) The metal powder precursor obtained in step (1) was placed in a porcelain boat, and then the porcelain boat containing the metal powder precursor was placed in a muffle furnace. The temperature was raised at a rate of 10° C. / min to 400° C. for 3 h. After natural cooling, the platinum-doped ruthenium oxide nanometer material was obtained, wherein a doping amount of platinum was 20%. A calculation formula of the doping amount of platinum was N platinum / (N platinum+N ruthenium)=20%.Example 39—Manganese-Doped Ruthenium Oxide

[0365] Referring to the method in Example 21, in the beaker, the concentration of a ruthenium chloride solution was 0.4 mol / L, the concentration of a manganese chloride solution was 0.1 mol / L, and the concentration of the polyvinylpyrrolidone in the beaker was 50 g / L. Reaction conditions in the oven were: a temperature of 100° C. for 4 h. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400°C. for 3 h.

[0366] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=20%.Example 40—Manganese-Doped Ruthenium Oxide

[0367] Referring to the method in Example 21, in the beaker, the concentration of a ruthenium chloride solution was 0.4 mol / L, the concentration of a manganese chloride solution was 0.1 mol / L, and the concentration of the polyvinylpyrrolidone in the beaker was 50 g / L. Reaction conditions in the oven were: a temperature of 180° C. for 4 h. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400°C. for 3 h.

[0368] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=20%.Example 41—Manganese-Doped Ruthenium Oxide

[0369] Referring to the method in Example 21, in the beaker, the concentration of a ruthenium chloride solution was 0.4 mol / L, the concentration of a manganese chloride solution was 0.1 mol / L, and the concentration of the polyvinylpyrrolidone in the beaker was 50 g / L. Reaction conditions in the oven were: a temperature of 100° C. for 10 h. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 400°C. for 3 h.

[0370] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=20%.Example 42—Manganese-Doped Ruthenium Oxide

[0371] Referring to the method in Example 21, in the beaker, the concentration of a ruthenium chloride solution was 0.4 mol / L, the concentration of a manganese chloride solution was 0.1 mol / L, and the concentration of the polyvinylpyrrolidone in the beaker was 50 g / L. Reaction conditions in the oven were: a temperature of 180° C. for 10 h. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 1° C. / min to a temperature of 300°C. for 3 h.

[0372] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=20%.Example 43—Manganese-Doped Ruthenium Oxide

[0373] Referring to the method in Example 21, in the beaker, the concentration of a ruthenium chloride solution was 0.4 mol / L, the concentration of a manganese chloride solution was 0.1 mol / L, and the concentration of the polyvinylpyrrolidone in the beaker was 50 g / L. Reaction conditions in the oven were: a temperature of 180° C. for 10 h. Calcination conditions of the muffle furnace were: the temperature was raised at a rate was 10° C. / min to a temperature of 500°C. for 5 h.

[0374] A doping amount of manganese in the manganese-doped ruthenium oxide nanometer material was 20%. A calculation formula of the doping amount of manganese was N manganese / (N manganese+N ruthenium)=20%.Application Example 7—Activity Test

[0375] A three-electrode system was used to test water electrolysis oxygen evolution performance of a manganese-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the manganese-doped ruthenium oxide nanometer material obtained in Examples 21 to 25 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L H2SO4 solution, and the polarization curves obtained were as shown in FIG. 53.

[0376] It can be seen from FIG. 53 that the manganese-doped ruthenium oxide nanometer materials obtained in Examples 21 to 25 has good water electrolysis oxygen evolution performance (curves A-E in FIG. 53), which is obviously superior to the commercial ruthenium dioxide material (curve F in FIG. 53), and overpotentials at a current density of 10 milliampere per square centimeter are 170 millivolts, 300 millivolts, 250 millivolts, 190 millivolts and 160 millivolts, respectively, which are all lower than 320 millivolts for the commercial ruthenium dioxide.Application Example 8—Stability Test

[0377] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of a manganese-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the manganese-doped ruthenium oxide nanometer material obtained in Examples 21, 24 or 25 or commercial ruthenium dioxide) and a cathode (a platinum gauze electrode).

[0378] FIG. 54 is a graph of the stability curves of the manganese-doped ruthenium oxide material obtained in Examples 21, 24 and 25 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 100 milliampere per square centimeter; and FIG. 55 is a graph of the stability curves of the manganese-doped ruthenium oxide material obtained in Examples 21, 24 and 25 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 200 milliampere per square centimeter.

[0379] It can be seen from FIG. 54 and FIG. 55 that, by being kept for 24 hours and 80-100 hours at the current densities of 100 and 200 milliampere per square centimeter respectively, the manganese-doped ruthenium oxide nanometer materials obtained in Examples 21, 24 and 25 barely attenuate in current, and the stability of this catalytic material at the large current density is obviously superior to the commercial ruthenium dioxide (see, e.g., FIG. 81). It also indicates that the manganese-doped ruthenium oxide nanometer material obtained in Examples 21, 24 and 25 has high stability at a large current density when used as the oxygen evolving reaction anode material.Application Example 9—Activity Test

[0380] A three-electrode system was used to test water electrolysis oxygen evolution performance of a manganese-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the manganese-doped ruthenium oxide nanometer material obtained in Example 21 and Comparative Example 3 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L H2SO4 solution, and the polarization curves obtained were as shown in FIG. 56.

[0381] It can be seen from FIG. 56 that the manganese-doped ruthenium oxide nanometer materials obtained in Example 21 and Comparative Example 3 have good water electrolysis oxygen evolution performance (curves A and B in FIG. 56), which is obviously superior to the commercial ruthenium dioxide material (curve C in FIG. 56), and overpotentials at a current density of 10 milliampere per square centimeter are 170 millivolts and 220 millivolts respectively, which are both lower than 320 millivolts for the commercial ruthenium dioxide.Application Example 10—Stability Test

[0382] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of a manganese-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the manganese-doped ruthenium oxide nanometer material obtained in Example 21 or Comparative Example 3 or commercial ruthenium dioxide) and a cathode (a platinum gauze electrode).

[0383] FIG. 57 is a stability curve of the manganese-doped ruthenium oxide material obtained in Comparative Example 3 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 100 milliampere per square centimeter; and FIG. 58 is a stability curve of the manganese-doped ruthenium oxide material obtained in Comparative Example 3 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 200 milliampere per square centimeter.

[0384] It can be seen from FIG. 57 and FIG. 58 that, by being kept for 24 hours and 100 hours at the current densities of 100 and 200 milliampere per square centimeter respectively, the manganese-doped ruthenium oxide nanometer material obtained in Comparative Example 3 attenuates in current at the large current density of 200 milliampere per square centimeter; and it indicates that the stability of the manganese-doped ruthenium oxide nanometer material obtained in the presence of ammonium citrate at the large current density when used as the oxygen evolving reaction anode material is inferior to the manganese-doped ruthenium oxide nanometer material obtained in Example 21.

[0385] Therefore, it is found in the present application example that, when the manganese-doped ruthenium oxide nanometer material formed in the presence of a multi-coordination-site high-molecular weight polymer is used as the oxygen evolving reaction anode material, compared to the manganese-doped ruthenium oxide nanometer material formed in the presence of ammonium citrate as the ligand, both the activity and the stability are improved.Application Example 11—Activity and Stability Test

[0386] A three-electrode system was used to test water electrolysis oxygen evolution performance of a manganese-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the manganese-doped ruthenium oxide nanometer material obtained in Example 21 or Comparative Example 4 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L H2SO4 solution, and the polarization curves obtained were as shown in FIG. 59.

[0387] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of a manganese-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the manganese-doped ruthenium oxide nanometer material obtained in Example 21 or Comparative Example 4 or the commercial ruthenium dioxide) and a cathode (the platinum gauze electrode).

[0388] It can be seen from FIG. 59 that the manganese-doped ruthenium oxide nanometer materials obtained in Example 21 and Comparative Example 4 have good water electrolysis oxygen evolution performance (curves B and A in FIG. 59), which is obviously superior to the commercial ruthenium dioxide material (curve C in FIG. 59), and overpotentials at a current density of 10 milliampere per square centimeter are 170 millivolts and 190 millivolts respectively, which are both lower than the 320 millivolts for the commercial ruthenium dioxide. The electrocatalytic activity of the manganese-doped ruthenium oxide nanometer material obtained in Example 21 used as the oxygen evolving reaction anode material is superior to the manganese-doped ruthenium oxide nanometer material obtained in Comparative Example 4.

[0389] FIG. 60 is a stability curve of the manganese-doped ruthenium oxide material obtained in Comparative Example 4 as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 50 milliampere per square centimeter.

[0390] It can be seen from FIG. 60 that, by being kept for half an hour at the current density of 50 milliampere per square centimeter, the stability curve of the manganese-doped ruthenium oxide nanometer material obtained in Comparative Example 4 attenuates significantly within about 500 seconds; that is, this catalytic material has extremely poor stability at a small current density; and it indicates that the stability of the manganese-doped ruthenium oxide nanometer material obtained in Comparative Example 4 at larger current densities, when used as the oxygen evolving reaction anode material, is far inferior to the manganese-doped ruthenium oxide nanometer material obtained in Example 21. This proves that, compared to Example 21, both the electrocatalytic activity and the stability of the material prepared without adding the multi-coordination-site polymer (e.g., polyvinylpyrrolidone) are lowered greatly.

[0391] Therefore, it is found in the present application example that, when the manganese-doped ruthenium oxide nanometer material formed in the presence of a multi-coordination-site high-molecular weight polymer is used as the oxygen evolving reaction anode material, compared to the manganese-doped ruthenium oxide nanometer material formed without the multi-coordination-site high-molecular weight polymer, both the electrochemical activity and the stability are improved obviously.Application Example 12—Activity Test

[0392] A three-electrode system was used to test water electrolysis oxygen evolution performance of a chromium-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the chromium-doped ruthenium oxide nanometer material obtained in Example 26 or Comparative Example 5 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L H2SO4 solution, and the polarization curves obtained were as shown in FIG. 61.

[0393] It can be seen from FIG. 61 that the overpotential of the chromium-doped ruthenium oxide nanometer materials prepared in Example 26 and Comparative Example 5 at 10 milliampere per square centimeter in an oxygen evolving reaction is 180 millivolts (curve A and curve B in FIG. 61), which is obviously superior to the 320 millivolts for the commercial ruthenium dioxide material (curve C in FIG. 61). The nanometer materials obtained in Example 26 and Comparative Example 5 are roughly equivalent in electrochemical activity.Application Example 13—Stability test

[0394] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of a chromium-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the chromium-doped ruthenium oxide nanometer material obtained in Example 26 or Comparative Example 5 or commercial ruthenium dioxide) and a cathode (a platinum gauze electrode).

[0395] FIG. 62 is a stability curve of the chromium-doped ruthenium oxide material obtained in Example 26 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 100 milliampere per square centimeter; and FIG. 63 is a stability curve of the chromium-doped ruthenium oxide material obtained in Example 26 of the present invention as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 200 milliampere per square centimeter.

[0396] It can be seen from FIG. 62 and FIG. 63 that, by being kept for 24 hours and 100 hours at the current densities of 100 and 200 milliampere per square centimeter respectively, the chromium-doped ruthenium oxide nanometer material obtained in Example 26 barely attenuates in current, and the stability of this catalytic material at large current densities is obviously superior to the commercial ruthenium dioxide (see, e.g., FIG. 81). It also indicates that the chromium-doped ruthenium oxide nanometer material obtained in Example 26 has high stability at a large current density when used as the oxygen evolving reaction anode material. FIG. 64 is a stability curve of the chromium-doped ruthenium oxide material obtained in Comparative Example 5 as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 100 milliampere per square centimeter; and FIG. 65 is a stability curve of the chromium-doped ruthenium oxide material obtained in Comparative Example 5 as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 200 milliampere per square centimeter.

[0397] It can be seen from FIG. 64 and FIG. 65 that, by being kept for 24 hours and 100 hours at the current densities of 100 and 200 milliampere per square centimeter respectively, the chromium-doped ruthenium oxide nanometer material obtained in Comparative Example 5 attenuates significantly in current at a current density of 200 milliampere per square centimeter. It also indicates that the stability of the chromium-doped ruthenium oxide nanometer material obtained in the presence of ammonium citrate at large current densities, when used as the oxygen evolving reaction anode material, is inferior to the chromium-doped ruthenium oxide nanometer material obtained in Example 26.

[0398] Therefore, it is found in the present application example that, when the chromium-doped ruthenium oxide nanometer material formed in the presence of a multi-coordination-site high-molecular weight polymer is used as the oxygen evolving reaction anode material, compared to the chromium-doped ruthenium oxide nanometer material formed in the presence of ammonium citrate as the ligand, the stability is noticeably improved.Application Example 14—Activity and Stability Test

[0399] A three-electrode system was used to test water electrolysis oxygen evolution performance of a chromium-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the chromium-doped ruthenium oxide nanometer material obtained in Example 26 or Comparative Example 6 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L H2SO4 solution, and the polarization curves obtained were as shown in FIG. 66.

[0400] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of the chromium-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the chromium-doped ruthenium oxide nanometer material obtained in Example 26 or Comparative Example 6 or the commercial ruthenium dioxide) and a cathode (the platinum gauze electrode).

[0401] It can be seen from FIG. 66 that the chromium-doped ruthenium oxide nanometer material obtained in Example 26 and Comparative Example 6 has good water electrolysis oxygen evolution performance (curves B and A in FIG. 66), which are obviously superior to the commercial ruthenium dioxide material (curve C in FIG. 66), and the overpotential at a current density of 10 milliampere per square centimeter is 170 millivolts, which is lower than the 320 millivolts for the commercial ruthenium dioxide. The electrocatalytic activity of the chromium-doped ruthenium oxide nanometer material obtained in Example 26 used as an oxygen evolving reaction anode material is roughly equivalent to the chromium-doped ruthenium oxide nanometer material obtained in Comparative Example 6.

[0402] FIG. 67 is a stability curve of the chromium-doped ruthenium oxide material obtained in Comparative Example 6 as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 50 milliampere per square centimeter.

[0403] It can be seen from FIG. 67 that, by being kept for half an hour at the current density of 50 milliampere per square centimeter, the stability curve of the chromium-doped ruthenium oxide nanometer material obtained in Comparative Example 6 quickly attenuates (e.g., within 80 seconds): that is, this catalytic material has extremely poor stability at a relatively small current density. It also indicates that the stability of the chromium-doped ruthenium oxide nanometer material obtained in Comparative Example 6 at larger current density when used as the oxygen evolving reaction anode material is far inferior to the chromium-doped ruthenium oxide nanometer material obtained in Example 26.

[0404] Therefore, it is found in the present application example that, when the chromium-doped ruthenium oxide nanometer material is formed in the presence of a multi-coordination-site high-molecular weight polymer, its use as an oxygen evolving reaction anode material, compared to the manganese-doped ruthenium oxide nanometer material formed without the multi-coordination-site high-molecular weight polymer, improves the stability significantly.Application Example 15—Activity Test

[0405] A three-electrode system was used to test water electrolysis oxygen evolution performance of a tin-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the tin-doped ruthenium oxide nanometer material obtained in Example 27 or Comparative Example 7 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L H2SO4 solution, and the polarization curves obtained were as shown in FIG. 68.

[0406] It can be seen from FIG. 68 that the tin-doped ruthenium oxide nanometer material obtained in Example 27 has good water electrolysis oxygen evolution performance (curve A in FIG. 68), which is obviously superior to the tin-doped ruthenium oxide nanometer material obtained in Comparative Example 7 (curve B in FIG. 68) and the commercial ruthenium dioxide material (curve C in FIG. 68), and the overpotential at a current density of 10 milliampere per square centimeter is 170 millivolts, which is obviously lower than the 220 millivolts for the material obtained in Comparative Example 7 and the 320 millivolts for the commercial ruthenium dioxide. It proves that the tin-doped ruthenium oxide nanometer material obtained in Example 27 has better oxygen evolving reaction activity than the tin-doped ruthenium oxide nanometer material made using ammonium citrate in Comparative Example 7 and the commercial ruthenium dioxide.Application Example 16—Stability Test

[0407] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of a tin-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the tin-doped ruthenium oxide nanometer material obtained in Example 27 or commercial ruthenium dioxide) and a cathode (a platinum gauze electrode).

[0408] FIG. 69 is a stability curve of the tin-doped ruthenium oxide material obtained in Example 27 of the present invention, used as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 100 milliampere per square centimeter; and FIG. 70 is a stability curve of the tin-doped ruthenium oxide material obtained in Example 27 of the present invention, used as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 200 milliampere per square centimeter.

[0409] It can be seen from FIG. 69 and FIG. 70 that, by being kept for 24 hours and 80 hours at the current densities of 100 and 200 milliampere per square centimeter, respectively, the tin-doped ruthenium oxide nanometer material obtained in Example 27 barely attenuates in current, and the stability of this catalytic material at large current densities is obviously superior to the commercial ruthenium dioxide. It also indicates that the tin-doped ruthenium oxide nanometer material obtained in Example 27 has high stability at a large current density when used as the oxygen evolving reaction anode material.

[0410] FIG. 71 is a stability curve of the tin-doped ruthenium oxide material obtained in Comparative Example 7, used as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 100 milliampere per square centimeter; and FIG. 72 is a stability curve of the tin-doped ruthenium oxide material obtained in Comparative Example 7, used as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 200 milliampere per square centimeter.

[0411] It can be seen from FIG. 71 and FIG. 72 that, by being kept for 24 hours and 100 hours at the current densities of 100 and 200 milliampere per square centimeter, respectively, the tin-doped ruthenium oxide nanometer material obtained in Comparative Example 7 attenuates in current at the large current density of 200 milliampere per square centimeter. However, the stability of this catalytic material at one or more large current densities is obviously superior to the commercial ruthenium dioxide; and it indicates that the stability of the tin-doped ruthenium oxide nanometer material made in the presence of ammonium citrate at large current densities when used as the oxygen evolving reaction anode material is superior to the commercial ruthenium dioxide, but inferior to the tin-doped ruthenium oxide nanometer material obtained in Example 27.

[0412] Therefore, it is found in the present application example that, when the tin-doped ruthenium oxide nanometer material is made in the presence of a multi-coordination-site high-molecular weight polymer and used as the oxygen evolving reaction anode material, compared to the tin-doped ruthenium oxide nanometer material made in the presence of ammonium citrate as a ligand, both the activity and the stability are improved significantly.Application Example 17—Activity and Stability Test

[0413] A three-electrode system was used to test water electrolysis oxygen evolution performance of a tin-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the tin-doped ruthenium oxide nanometer material obtained in Example 27 or Comparative Example 8 or commercial ruthenium dioxide). Testing was carried out in a 0.5 mol / L H2SO4 solution, and the polarization curves obtained were as shown in FIG. 73.

[0414] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of the tin-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the tin-doped ruthenium oxide nanometer material obtained in Example 27 or Comparative Example 8 or commercial ruthenium dioxide) and a cathode (the platinum gauze electrode).

[0415] It can be seen from FIG. 73 that the tin-doped ruthenium oxide nanometer material obtained in Example 27 and Comparative Example 8 has good water electrolysis oxygen evolution performance (curves B and A in FIG. 73), which is obviously superior to the commercial ruthenium dioxide material (curve C in FIG. 73), and overpotentials at a current density of 10 milliampere per square centimeter are 146 millivolts and 190 millivolts respectively, which are both lower than the 320 millivolts for the commercial ruthenium dioxide. However, the electrocatalytic activity of the tin-doped ruthenium oxide nanometer material obtained in Example 27, when used as the oxygen evolving reaction anode material, is obviously superior to the tin-doped ruthenium oxide nanometer material obtained in Comparative Example 8.

[0416] FIG. 74 is a stability curve of the tin-doped ruthenium oxide material obtained in Comparative Example 8 as an oxygen evolution anode material in a 0.5 mol / L H2SO4 solution at a current density of 100 milliampere per square centimeter.

[0417] It can be seen from FIG. 74 that, by being kept for 24 hours at the current density of 100 milliampere per square centimeter, the stability curve of the tin-doped ruthenium oxide nanometer material obtained in Comparative Example 8 attenuates by 175 millivolts in 24 hours; that is, this catalytic material has extremely poor stability at a relatively large current density. It also indicates that the stability of the tin-doped ruthenium oxide nanometer material obtained in Comparative Example 8 at the large current density when used as the oxygen evolving reaction anode material is far inferior to the tin-doped ruthenium oxide nanometer material obtained in Example 27.

[0418] Therefore, it is found in the present application example that, when the tin-doped ruthenium oxide nanometer material made in the presence of a multi-coordination-site high-molecular weight polymer is used as the oxygen evolving reaction anode material, compared to the tin-doped ruthenium oxide nanometer material made without the multi-coordination-site high-molecular weight polymer, both the activity and the stability are improved significantly.Application Example 18—Activity and Stability Test

[0419] A three-electrode system was used to test water electrolysis oxygen evolving reaction activity of germanium, indium, antimony, niobium, titanium, zirconium, hafnium, tungsten, molybdenum, tantalum and platinum-doped ruthenium oxide nanometer materials of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the transition metal-doped ruthenium oxide nanometer material obtained in Examples 28 to 38 or commercial ruthenium dioxide).

[0420] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of the transition metal-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the transition metal-doped ruthenium oxide nanometer material obtained in Examples 28 to 38 or the commercial ruthenium dioxide) and a cathode (the platinum gauze electrode).

[0421] FIG. 75 is a graph showing polarization curves obtained by testing transition metal-doped ruthenium oxide materials obtained in Examples 28 to 32 in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 75 that the overpotential of the germanium-doped ruthenium oxide nanometer material prepared in Example 28 at 10 milliampere per square centimeter in the oxygen evolving reaction is 180 millivolts (curve A in FIG. 75), the overpotential of the indium-doped ruthenium oxide nanometer material prepared in Example 29 at 10 milliampere per square centimeter in the oxygen evolving reaction is 200 millivolts (curve B in FIG. 75), the overpotential of the antimony-doped ruthenium oxide nanometer material prepared in Example 30 at 10 milliampere per square centimeter in the oxygen evolving reaction is 180 millivolts (curve C in FIG. 75), the overpotential of the niobium-doped ruthenium oxide nanometer material prepared in Example 31 at 10 milliampere per square centimeter in the oxygen evolving reaction is 180 millivolts (curve D in FIG. 75), and the overpotential of the titanium-doped ruthenium oxide nanometer material prepared in Example 32 at 10 milliampere per square centimeter in the oxygen evolving reaction is 250 millivolts (curve E in FIG. 75). This data proves that the oxygen evolving reaction activities of the transition metal-doped ruthenium oxide nanometer materials prepared in Examples 28 to 32 are obviously superior to the commercial ruthenium dioxide (curve F in FIG. 75).

[0422] FIG. 76 is a graph showing polarization curves obtained by testing transition metal-doped ruthenium oxide materials obtained in Examples 33 to 38 in a 0.5 mol / L H2SO4 solution. The overpotential of the zirconium-doped ruthenium oxide nanometer material prepared in Example 33 at 10 milliampere per square centimeter in the oxygen evolving reaction is 270 millivolts (curve A in FIG. 76), the overpotential of the hafnium-doped ruthenium oxide nanometer material prepared in Example 34 at 10 milliampere per square centimeter in the oxygen evolving reaction is 270 millivolts (curve B in FIG. 76), the overpotential of the tungsten-doped ruthenium oxide nanometer material prepared in Example 35 at 10 milliampere per square centimeter in the oxygen evolving reaction is 250 millivolts (curve C in FIG. 76), the overpotential of the molybdenum-doped ruthenium oxide nanometer material prepared in Example 36 at 10 milliampere per square centimeter in the oxygen evolving reaction is 240 millivolts (curve D in FIG. 76), the overpotential of the tantalum-doped ruthenium oxide nanometer material prepared in Example 37 at 10 milliampere per square centimeter in the oxygen evolving reaction is 220 millivolts (curve E in FIG. 76), and the overpotential of the platinum-doped ruthenium oxide nanometer material prepared in Example 38 at 10 milliampere per square centimeter in the oxygen evolving reaction is 222 millivolts (curve F in FIG. 76). This data proves that the oxygen evolving reaction activities of the transition metal-doped ruthenium oxide nanometer materials prepared in Examples 33 to 38 are obviously superior to the commercial ruthenium dioxide (curve G in FIG. 76).

[0423] FIG. 77 is a graph showing stability curves obtained from the transition metal-doped ruthenium oxide materials obtained in Examples 28 to 32 at a current density of 200 milliampere per square centimeter. Curve A is the stability curve of the germanium-doped ruthenium oxide prepared in Example 28, curve B is the stability curve of the indium-doped ruthenium oxide prepared in Example 29, curve C is the stability curve of the antimony-doped ruthenium oxide prepared in Example 30, curve D is the stability curve of the niobium-doped ruthenium oxide prepared in Example 31, and curve E is the stability curve of the titanium-doped ruthenium oxide prepared in Example 32. It can be seen from FIG. 77 that, by being kept for 80 hours at the current density of 200 milliampere per square centimeter, the transition metal-doped ruthenium oxide nanometer materials obtained in Examples 28 to 32 barely attenuate in current; and compared to the commercial ruthenium dioxide, in a stability test at a current density of 100 milliampere per square centimeter, the stability curve of the commercial ruthenium dioxide is attenuated by 500 millivolts or above after being tested for 1 hour (see, e.g., FIG. 81). It indicates that the transition metal-doped ruthenium oxide nanometer materials have extremely high stability at a large current density when used as an oxygen evolving reaction anode material.

[0424] FIG. 78 is a graph showing stability curves obtained from the transition metal-doped ruthenium oxide materials obtained in Examples 33 to 38 at a current density of 200 milliampere per square centimeter. Curve A is the stability curve of the zirconium-doped ruthenium oxide prepared in Example 33, curve B is the stability curve of the hafnium-doped ruthenium oxide prepared in Example 34, curve C is the stability curve of the tungsten-doped ruthenium oxide prepared in Example 35, curve D is the stability curve of the molybdenum-doped ruthenium oxide prepared in Example 36, curve E is the stability curve of the tantalum-doped ruthenium oxide prepared in Example 37, and curve F is the stability curve of the platinum-doped ruthenium oxide prepared in Example 38. It can be seen from FIG. 78 that, by being kept for 80 hours at the current density of 200 milliampere per square centimeter, the transition metal-doped ruthenium oxide nanometer materials obtained in Examples 33 to 38 barely attenuate in current; and compared to the commercial ruthenium dioxide, in a stability test at a current density of 100 milliampere per square centimeter, a stability curve of the commercial ruthenium dioxide is attenuated by 500 millivolts or above after being tested for 1 hour (see, e.g., FIG. 81). It indicates that the above transition metal-doped ruthenium oxide nanometer materials have extremely high stability at a large current density when used as an oxygen evolving reaction anode material.Application Example 19—Activity and Stability Test

[0425] A three-electrode system was used to test water electrolysis oxygen evolving reaction activity of a manganese-doped ruthenium oxide nanometer material of the present invention. The system included a reference electrode (a calomel electrode), a counter electrode (a platinum gauze electrode), and a working electrode (the manganese-doped ruthenium oxide nanometer material obtained in Examples 39 to 43 or commercial ruthenium dioxide).

[0426] A two-electrode system was used to test water electrolysis oxygen evolving reaction stability of the manganese-doped ruthenium oxide nanometer material of the present invention. The system included an anode (the manganese-doped ruthenium oxide nanometer material obtained in Examples 39 to 43 or the commercial ruthenium dioxide) and a cathode (the platinum gauze electrode).

[0427] FIG. 79 is a graph showing polarization curves obtained by testing the manganese-doped ruthenium oxide material obtained in Examples 39 to 43 in a 0.5 mol / L sulfuric acid solution. It can be seen from FIG. 79 that the overpotential of the manganese-doped ruthenium oxide nanometer material prepared in Example 39 at 10 milliampere per square centimeter in the oxygen evolving reaction is 310 millivolts (curve A in FIG. 79), the overpotential of the manganese-doped ruthenium oxide nanometer material prepared in Example 40 at 10 milliampere per square centimeter in the oxygen evolving reaction is 220 millivolts (curve B in FIG. 79), the overpotential of the manganese-doped ruthenium oxide nanometer material prepared in Example 41 at 10 milliampere per square centimeter in the oxygen evolving reaction is 220 millivolts (curve C in FIG. 79), the overpotential of the manganese-doped ruthenium oxide nanometer material prepared in Example 42 at 10 milliampere per square centimeter in the oxygen evolving reaction is 200 millivolts (curve D in FIG. 79), and the overpotential of the manganese-doped ruthenium oxide nanometer material prepared in Example 43 at 10 milliampere per square centimeter in the oxygen evolving reaction is 200 millivolts (curve E in FIG. 79). This data also proves that the oxygen evolving reaction activities of the manganese-doped ruthenium oxide nanometer material prepared in Examples 39 to 43 are superior to the 320 millivolts for the commercial ruthenium dioxide (curve F in FIG. 75).

[0428] FIG. 80 is a graph showing stability curves obtained from the manganese-doped ruthenium oxide materials obtained in Examples 39 to 43 at a current density of 200 milliampere per square centimeter. Curve A is the stability curve of the manganese-doped ruthenium oxide prepared in Example 39, curve B is the stability curve of the manganese-doped ruthenium oxide prepared in Example 40, curve C is the stability curve of the manganese-doped ruthenium oxide prepared in Example 41, curve D is the stability curve of the manganese-doped ruthenium oxide prepared in Example 42, and curve E is the stability curve of the manganese-doped ruthenium oxide prepared in Example 43. It can be seen from FIG. 80 that, by being kept for 24 hours at the current density of 200 milliampere per square centimeter, the manganese-doped ruthenium oxide nanometer materials obtained in Examples 39 to 43 barely attenuate in current; and compared to the commercial ruthenium dioxide, in a stability test at a current density of 100 milliampere per square centimeter, a stability curve of the commercial ruthenium dioxide is attenuated by 500 millivolts or above after being tested for 1 hour (see, e.g., FIG. 81). It also indicates that the above manganese-doped ruthenium oxide nanometer materials have extremely high stability at a large current density when used as an oxygen evolving reaction anode material. As for experiment conditions, compared to Application Example 7 and Application Example 8, optimal reaction conditions in step 1 and step 2 are: an oven temperature of 180° C., and a time of 10 h. The temperature of the muffle furnace was raised at a rate of 10° C. / min, the temperature was 400° C., and the heating time was 3 h.

[0429] FIG. 53 to FIG. 81 show that, in a water electrolysis process, the transition metal-doped ruthenium oxide nanometer material of the present invention has excellent activity and stability as an oxygen evolving reaction anode material, which are both superior to the commercial ruthenium dioxide material.

[0430] The above sufficiently proves that, through the addition of the high-molecular weight polymer having the plurality of coordinatable groups in combination with the simple hydrothermal method and calcination, transition metal-doped ruthenium oxide nanometer materials are prepared that have a surface with rough nanometer structures, and with the addition of the high-molecular weight polymer multidentate ligand, the electrochemical oxygen evolving reaction activity and stability of such materials are greatly improved.

Claims

1. A metal-doped ruthenium oxide nanometer material having a molecular formula MxRu1-xO2, wherein the metal-doped ruthenium oxide nanometer material comprises an acid-insoluble metal oxide-doped ruthenium oxide nanometer material or a transition metal-doped ruthenium oxide nanometer material;M in the acid-insoluble metal oxide-doped ruthenium oxide nanometer material is selected from niobium, titanium, zirconium, hafnium, tungsten, molybdenum, and tantalum; andM in the transition metal-doped ruthenium oxide nanometer material is selected from Cr, Mn, Ge, In, Sn, Sb, Nb, Ti, Zr, Hf, W, Mo, Ta, and Pt.

2. The metal-doped ruthenium oxide nanometer material according to claim 1, wherein the metal-doped ruthenium oxide nanometer material is the acid-insoluble metal oxide-doped ruthenium oxide nanometer material, the acid-insoluble metal oxide-doped ruthenium oxide nanometer material includes a ruthenium oxide lattice, and atoms of the metal replace ruthenium atoms in the ruthenium oxide lattice.

3. The metal-doped ruthenium oxide nanometer material according to claim 1, wherein the metal-doped ruthenium oxide nanometer material is the transition metal-doped ruthenium oxide nanometer material, the transition metal-doped ruthenium oxide nanometer material includes a ruthenium oxide crystal lattice, and atoms of the transition metal replace ruthenium atoms in the crystal lattice.

4. The metal-doped ruthenium oxide nanometer material according to claim 1, wherein M and ruthenium are uniformly dispersed in the metal-doped ruthenium oxide nanometer material, the metal-doped ruthenium oxide nanometer material comprises nanoparticles with a rough and porous surface, and the nanoparticles have a size that ranges from 5 nm to 2000 nm.

5. The metal-doped ruthenium oxide nanometer material according to claim 1, wherein M is present in a ratio that ranges from 1% to 50%, based on a total quantity of moles or atoms of the transition metal and the ruthenium in the transition metal-doped ruthenium oxide nanometer material.

6. A method of preparing the metal-doped ruthenium oxide nanometer material according to claim 1, wherein the metal-doped ruthenium oxide nanometer material is the acid-insoluble metal oxide-doped ruthenium oxide nanometer material; and the method comprises a sol-gel method that comprises:placing a ligand into a solution containing an acid-insoluble metal oxide source and a ruthenium source to obtain a mixture, sealing and mixing the mixture in a container at a constant temperature for 1-48 hours, then opening the container, volatilizing any solvent, and removing a remaining solid to obtain a metal complex precursor; andplacing the metal complex precursor into a muffle furnace, raising a temperature to a reaction temperature, maintaining the reaction temperature for 1-24 hours, and removing a product to obtain the acid-insoluble metal oxide-doped ruthenium oxide nanometer material.

7. The method according to claim 6, wherein the acid-insoluble metal oxide source is selected from a metal chloride, a metal organic carboxylate, and a metal carbonyl compound;the ruthenium source is a ruthenium chloride compound, a ruthenium diketonate, a ruthenium carbonyl compound, or a ruthenium nitrosylnitrate; andthe ligand is a polymer containing a plurality of coordinatable groups.

8. The method according to claim 7, wherein the polymer containing the plurality of coordinatable groups is selected from polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene diamine, polylactic acid, polypyridine and polyamides.

9. The method according to claim 6, wherein a concentration of the acid-insoluble metal oxide source in the mixture ranges from 0.01 mol / L to 1 mol / L, and a concentration of the ruthenium source in the mixture ranges from 0.1 mol / L to 1 mol / L.

10. The method according to claim 6, wherein, in step (2), the temperature is raised at a rate that ranges from 1° C. / min to 10° C. / min, the reaction temperature ranges from 400° C. to 600° C., and reaction temperature is preserved for a time that ranges from 3 hours to 6 hours.

11. A method of preparing the metal-doped ruthenium oxide nanometer material according to claim 1, wherein the metal-doped ruthenium oxide nanometer material is the acid-insoluble metal oxide-doped ruthenium oxide nanometer material, and the method comprises a solvothermal method that comprises:placing a solution of an acid-insoluble metal oxide source and a ruthenium source into a hydrothermal reactor, adding an alkali source to obtain a reaction liquid, placing the hydrothermal reactor into an oven, heating the oven to a temperature of 100° C. to 200° C., maintaining the temperature for 8 to 16 hours, and removing a reaction product to obtain a powder; andplacing the powder into a porcelain boat and placing the porcelain boat into a muffle furnace, raising a temperature of the muffle furnace at a rate that ranges from 5° C. / min to 10° C. / min to a reaction temperature of 400° C. to 600° C., and maintaining the reaction temperature for 2 to 8 hours to obtain the acid-insoluble metal oxide-doped ruthenium oxide nanometer material.

12. The method according to claim 11, wherein the reaction liquid has a concentration of the acid-insoluble metal oxide source that ranges from 0.001 mol / L to 1 mol / L, a concentration of the ruthenium source that ranges from 0.1 mol / L to 1 mol / L, and a concentration of the alkali source that ranges from 1 g / L to 5 g / L.

13. A method of preparing the metal-doped ruthenium oxide nanometer material according to claim 1, wherein the metal-doped ruthenium oxide nanometer material is the acid-insoluble metal oxide-doped ruthenium oxide nanometer material, and the method comprises a ball milling method that comprises:placing ruthenium oxide and an acid-insoluble metal oxide into a ball milling tank in a mole ratio of the ruthenium oxide to the acid-insoluble metal oxide from 99:1 to 1:1, ball milling the ruthenium oxide and the acid-insoluble metal oxide for 3 to 6 hours, repeating the ball milling 2 to 3 times to obtain a precursor powder, placing the precursor powder into a porcelain boat, placing the porcelain boat into a muffle furnace, raising a temperature of the muffle furnace at a rate that ranges from 5° C. / min to 10° C. / min to a reaction temperature of 400° C. to 800° C., and maintaining the reaction temperature for 6 to 12 hours to obtain a black powder sample, thus obtaining the acid-insoluble metal oxide-doped ruthenium oxide nanometer material.

14. An electrode comprising the metal-doped ruthenium oxide nanometer material according to claim 1.

15. The electrode according to claim 14, wherein the metal-doped ruthenium oxide nanometer material is in an anode adapted for electrolysis of water.

16. A method of preparing the metal-doped ruthenium oxide nanometer material according to claim 1, wherein M is the transition metal, and the method comprises a hydrothermal method that comprises:forming a solution containing a soluble transition metal source and a soluble ruthenium source, then adding a polymer containing a plurality of coordinatable groups, mixing the solution and the polymer to obtain a mixture, transferring the mixture into a hydrothermal reactor, reacting the mixture in a constant temperature oven, removing the mixture, and washing, centrifuging, and drying a resulting product to obtain a precursor containing the transition metal; andplacing the precursor containing the transition metal into a muffle furnace, raising a temperature of the muffle furnace to a reaction temperature, maintaining the reaction temperature for 1-24 hours, and removing a resulting product to obtain the transition metal-doped ruthenium oxide nanometer material.

17. The method according to claim 16, wherein the soluble transition metal source is selected from a transition metal chloride, a transition metal high-valence compound, a transition metal organic carboxylate, and a transition metal carbonyl compound;the ruthenium source is selected from ruthenium chloride, a ruthenium diketonate, a ruthenium carbonyl compound and ruthenium nitrosylnitrate; andthe polymer containing the plurality of coordinatable groups is selected from polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene diamine, polylactic acid, polypyridine and polyamides.

18. The method according to claim 17, wherein the mixture has a concentration of the transition metal source that ranges from 0.001 mol / L to 1 mol / L, a concentration of the ruthenium source that ranges from 0.1 mol / L to 1 mol / L, and a concentration of the polymer that ranges from 1 g / L to 50 g / L.

19. The method according to claim 16, wherein further comprising heating the constant temperature oven to a temperature of from 100° C. to 180° C. for a time that ranges from 4 hours to 10 hours.

20. The method according to claim 16, wherein the temperature of the muffle furnace is raised at a rate that ranges from 1° C. / min to 10° C. / min, the reaction temperature ranges from 300° C. to 500° C., and the reaction temperature is maintained for 3 hours to 5 hours.

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