Alkaline electrolytic water hydrogen evolution reaction nickel-based electrode and preparation method and application thereof

Abstract

The invention provides an alkaline electrolytic water hydrogen evolution reaction nickel-based electrode and a preparation method and application thereof, and belongs to the technical field of catalyst materials. The alkaline electrolytic water hydrogen evolution reaction nickel-based electrode has a monatomic-nanocluster-nanoparticle-support multilevel structure, the multilevel structure takes a metal nickel net as a support, nickel is loaded on the metal nickel net in the form of particles, molybdenum oxide is dispersed on the nickel particles in the form of clusters, and the metal nickel net is supported on the support. The preparation method comprises the following steps: preparing molybdenum oxide clusters, anchoring platinum on the molybdenum oxide clusters in the form of single atoms, loading nickel particles on a metal nickel net by utilizing a plasma spraying method, generating the molybdenum oxide clusters on the nickel particles through thermal annealing treatment, and then loading platinum single atoms on the molybdenum oxide clusters by utilizing an electrodeposition method, therefore, the nickel-based electrode for the hydrogen evolution reaction of the alkaline electrolyzed water is obtained. According to the invention, the hydrogen evolution reaction electrode with a multi-stage structure is prepared from a microreaction mechanism for the first time, the preparation cost is low, industrial production can be realized, and the hydrogen evolution reaction electrode can be applied to industrial hydrogen production.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst materials, and particularly relates to a nickel-based electrode for alkaline water electrolysis hydrogen evolution reaction, a preparation method thereof, and an application thereof. Background Art

[0002] At present, fossil energy is one of the main energy sources. However, with the increase in global energy consumption, the reserves of fossil energy are gradually decreasing, and the problem of shortage is becoming increasingly prominent. At the same time, the use of fossil energy has also led to problems such as environmental pollution and climate change, which have had a serious impact on human society and the natural environment. Therefore, the development of new energy has become an inevitable choice in today's world. New energy sources such as solar energy, wind energy, water energy, and geothermal energy are inexhaustible and can not only effectively reduce the dependence on fossil energy but also reduce environmental damage and achieve sustainable development. Therefore, the development of new energy can not only solve the problem of energy shortage but also promote economic development, improve energy utilization efficiency, improve environmental quality, and promote social harmony. Therefore, increasing the research and application of new energy and promoting the development of the new energy industry have become the common efforts of all countries in the world.

[0003] New energy represented by hydrogen energy has quickly become a research hotspot due to its energy-saving, environmentally friendly, and efficient characteristics. Among them, hydrogen energy is divided into green hydrogen and grey hydrogen, which refer to hydrogen produced by different production methods. Green hydrogen refers to the method of producing hydrogen by using renewable energy (such as solar energy, wind energy, etc.), which is an environmentally friendly and sustainable production method. Grey hydrogen, on the other hand, refers to the method of producing hydrogen by using traditional fossil fuels (such as coal, natural gas, etc.), which will produce a large amount of greenhouse gases such as carbon dioxide and have a negative impact on the environment. Therefore, green hydrogen is considered the future direction of hydrogen energy development, while grey hydrogen is gradually being phased out.

[0004] Green hydrogen is a clean energy source derived from water splitting. For the production of green hydrogen, it is currently mainly obtained through the electrocatalytic splitting of water. Water electrolysis technology is a method of splitting water into hydrogen and oxygen through an electrochemical process. This method is regarded as a potential means of clean and sustainable energy production, especially when using renewable energy electricity. Water electrolysis technology can be traced back to the early 19th century when scientists discovered the possibility of splitting water through an electric current. However, due to early technological limitations and high costs, this method was not widely applied. In the second half of the 20th century, with the increasing demand for clean energy and technological progress, water electrolysis hydrogen production technology has attracted people's attention again. Currently, water electrolysis technology mainly adopts three technical routes, including: Alkaline Water Electrolysis (AWE), which is the most mature electrolysis technology with relatively low costs, but has limitations in terms of efficiency and operating pressure; Proton Exchange Membrane (PEM), this technology can operate at higher current densities, has high efficiency, fast response speed, and is suitable for intermittent renewable energy power supply, but the cost is high; Solid Oxide Electrolysis Cell (SOEC), which can operate at high temperatures and theoretically can achieve higher energy efficiency, but has been in the laboratory stage before. With technological progress, SOEC is gradually moving towards commercial application.

[0005] Among them, alkaline water electrolysis technology, as a mature renewable energy conversion technology, is receiving increasing attention globally and is a relatively mature electrolytic water hydrogen production technology in industrialization. This technology decomposes water into oxygen and hydrogen by using direct current. The alkaline water hydrogen evolution reaction (HER, Hydrogen Evolution Reaction) is a process of generating hydrogen through an electrochemical method in an alkaline medium. This process occurs at the cathode of the electrolytic cell where water molecules accept electrons and are reduced to hydrogen. It mainly proceeds through the following steps: Volmer step: This is the first step and the rate-determining step. In this process, water molecules adsorb on the catalyst surface, obtain an electron from the electrode, and release a hydrogen ion (proton) simultaneously, forming an adsorbed hydrogen atom (H*): H2O(l) + e - →H* + OH - (aq); Heyrovsky step: An adsorbed hydrogen atom (H*) can obtain a proton (H + ) from a water molecule in the solution and combine with another adsorbed hydrogen atom (H*) to form a hydrogen molecule (H2), and at the same time, this process also releases a hydroxyl ion (OH -)Back to the solution: H* + H2O + e - → H2 + OH - ; Tafel step: Two adjacent adsorbed hydrogen atoms (H*) directly interact with each other to combine and form a hydrogen molecule (H2): 2H* → H2. Finally, the formed hydrogen molecule (H2) needs to desorb from the electrode surface into the solution or gas phase. Under alkaline conditions, for example, when using KOH as the electrolyte, the generated OH - ions will move to the anode, lose electrons, and form oxygen (O2). While at the cathode, the above process repeats continuously to continuously generate hydrogen.

[0006] In recent years, the exploration of HER catalysts has been ongoing. Among them, noble metal-based catalysts have good catalytic activity, but due to their high cost and low reserves, they are not suitable for large-scale applications in actual production; although the activity of non-noble metal-based catalysts is somewhat insufficient compared to noble metals, less noble metal doping can be used to improve the catalytic activity of non-noble metal-based catalysts, thereby maximizing the utilization of noble metals. Single-atom catalysts have always been a research hotspot. Especially when there is a coordinated interaction between them and the support, not only can the theoretically maximum atomic utilization rate be achieved, but also the cost can be effectively reduced and applied to actual production. Noble metal platinum (Pt) has always been one of the best catalysts for the hydrogen evolution reaction. Its appropriate adsorption energy for intermediate hydrogen radicals can promote hydrogen adsorption and desorption, thereby accelerating the reaction rate. In recent years, there have been many studies on the hydrogen evolution reaction of Pt single atoms, most of which focus on the interaction between Pt single atoms and the support, such as the coordinated interaction between Pt single atoms and nanoparticles, the coordinated interaction between Pt single atoms and nanoclusters, and the electronic effect. It mainly focuses on the electron gain and loss caused by the secondary structure due to its own structure and electron cloud density, thereby changing the adsorption or desorption free energy of different intermediates in the hydrogen evolution reaction, but there is still a problem of low utilization rate.

[0007] Therefore, to solve the defects of low noble metal atom utilization rate, low product selectivity, low catalytic activity, and short catalytic life time in the existing technology for alkaline electrocatalytic hydrogen reaction (HER), the present invention designs a HER electrode with a multi-level structure, thereby realizing the industrial production application of alkaline electrolytic water hydrogen production. Summary of the Invention

[0008] To solve the above technical problems, the present invention proposes a nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction, its preparation method and application. The prepared nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction has a low and stable noble metal Pt loading amount and has a multi-level structure from micro to macro. Therefore, it has high catalytic activity, stable structure, and long service life.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] One of the technical solutions of the present invention:

[0011] A nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, having a multi-level structure of single atoms - nanoclusters - nanoparticles - support. The multi-level structure uses a metal nickel (Ni) mesh as the support, and nickel (Ni) is loaded on the metal Ni mesh in the form of particles. Molybdenum oxide (MoO x ) is dispersed on the Ni particles in the form of clusters, and platinum (Pt) is anchored on the MoO x clusters in the form of single atoms.

[0012] Furthermore, the loading amount of Pt accounts for 0.05 - 0.20% of the total mass of the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, preferably 0.05 - 0.185%.

[0013] The nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water of the present invention has a large specific surface area, which can provide more catalytic sites, thereby improving the electrocatalytic activity of HER. Among them, MoO x clusters are highly dispersed on the Ni particles, and the synergistic effect with the Ni particles can adjust the electron cloud density between atoms, increase the transfer energy barrier between electrons. Pt single atoms are loaded on the MoO x nanoclusters, which can provide the maximum atomic utilization rate of Pt in theory, and adjust the adsorption free energy of intermediates through coordination with the MoO x nanoclusters and Ni particles, thereby reducing the reaction energy consumption. Pt is loaded on the MoO x nanoclusters in the form of single atoms. Compared with Pt in the form of clusters or relatively dispersed Pt particles, the atomic utilization rate of Pt in the form of clusters or relatively dispersed Pt particles is low and the Pt size is large, blocking some active sites and reducing the adsorption amount of intermediates during the reaction process.

[0014] Another technical solution of the present invention:

[0015] A preparation method of the above-mentioned nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, which uses the plasma spraying method to load nickel particles on a metal nickel mesh, and generates molybdenum oxide clusters on the nickel particles through heat annealing treatment, and then uses the electrodeposition method to load platinum single atoms on the molybdenum oxide clusters to obtain the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, including the following steps:

[0016] (1) Mix nickel molybdenum alloy powder and aluminum powder and dry them, and then spray them on a metal nickel mesh polished with emery by the plasma spraying method, and this process realizes loading nickel particles on the metal nickel mesh;

[0017] (2) Etch the sprayed metal nickel mesh after heat annealing treatment, and then wash and dry it, and this process realizes generating molybdenum oxide clusters on the nickel particles;

[0018] (3) Mix sodium hypophosphite and an aqueous solution of chloroplatinic acid to prepare an electrodeposition solution. Using the dried nickel mesh in step (2) as the cathode and a platinum plate electrode as the anode, perform electrodeposition. In this process, platinum single atoms are loaded onto molybdenum oxide clusters. After the electrodeposition is completed, take out the cathode, wash it, and obtain the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction.

[0019] Furthermore, in step (1) of the preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction, the mass ratio of the nickel-molybdenum alloy powder to the aluminum powder is (2 - 15):1; and / or,

[0020] The drying temperature is 30 - 80 °C and the time is 30 min; and / or,

[0021] The mesh number of the nickel mesh is 10 - 80 mesh and the wire diameter is 0.15 - 2.00 mm.

[0022] Furthermore, in the nickel-molybdenum alloy powder, the mass ratio of nickel to molybdenum is 8:1.

[0023] Furthermore, in step (1) of the preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction, the plasma spraying method is carried out in an inert atmosphere and / or a reducing atmosphere, and the powder feeding amount is 100 - 400 g·m -2 .

[0024] Furthermore, in step (2), the temperature of the thermal annealing treatment is 150 - 500 °C and the time is 1 - 24 h; and / or,

[0025] The etching is carried out with a KOH solution with a mass fraction of 10% - 30% for 10 - 20 h.

[0026] Furthermore, in step (3), the dosage ratio of sodium hypophosphite to the aqueous solution of chloroplatinic acid is (3 - 8) g:(1 - 1000) μL, and the concentration of the aqueous solution of chloroplatinic acid is 10 - 20 mg / mL; and / or,

[0027] The current of the electrodeposition is 5 - 100 mA and the treatment time is 1 - 20 h.

[0028] Furthermore, both the plasma spraying method and the thermal annealing treatment are carried out in an inert atmosphere and / or a reducing atmosphere. The inert atmosphere is selected from nitrogen or argon, and the reducing atmosphere is selected from hydrogen or CO.

[0029] More specifically, the preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction includes the following steps:

[0030] (1) Mix nickel-molybdenum alloy powder (mass ratio of nickel to molybdenum is 8:1) and aluminum powder in a mixer at a mass ratio of (2-15):1 for 20-60 min, then put them into an oven and dry at 30-80 °C for 30 min. After taking out, spray them evenly on a nickel mesh polished with emery using a plasma spraying machine. Set the powder feeding amount of the plasma spraying machine to 100-400 g·m -2 , the mesh number of the nickel mesh is 10-80 mesh, and the wire diameter is 0.15-2.00 mm;

[0031] (2) Heat-anneal the sprayed nickel mesh in a tubular furnace using an inert (nitrogen, argon), reducing atmosphere (hydrogen, CO) or a mixed reducing and inert atmosphere at 150-500 °C for 1-24 h, then etch it with a 10%-30% KOH solution by mass for 10-20 h. After that, wash it with deionized water until the washing liquid is neutral, and then wash the etched nickel mesh with deionized water, absolute ethanol, and acetone in turn, and dry it for standby;

[0032] (3) Put (3-8) g of sodium hypophosphite (NaH2PO2) and (1-1000) μL of an aqueous solution of chloroplatinic acid with a concentration of 10-20 mg / mL into a beaker, add deionized water to make up the volume to 60 mL to prepare an electrodeposition solution. Take the nickel mesh dried in step (2) as the cathode (2×2 cm), and a platinum plate electrode as the anode. Use a blue electrochemical workstation to set a constant current charge of 5-100 mA for 1-20 h for constant current electrodeposition. After the electrodeposition is completed, rinse it with deionized water and absolute ethanol to obtain the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction.

[0033] The presence of noble metal Pt has a great influence on the HER performance. In the common methods for preparing noble metal catalysts, there is often a process of high-temperature calcination, the purpose of which is to improve the stability and obtain a cluster-type noble metal catalyst when doping noble metals. However, in practical applications, the atomic utilization rate of the cluster-type catalyst is not high, which will cause some active sites not to be exposed to participate in the catalytic reaction. Therefore, the present invention does not apply the calcination strategy, but adopts an electrodeposition technique to make the atomic dispersion of noble metal Pt the highest, so that all catalytic sites are exposed, the adsorption energy barrier for intermediates is low, and the catalytic activity of the electrode is improved.

[0034] The third technical solution of the present invention:

[0035] The present invention also discloses an application of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction in electrolytic water hydrogen production.

[0036] Further, use the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction as the working electrode, a platinum plate as the counter electrode, and a saturated calomel electrode (SCE) as the reference electrode.

[0037] Compared with the prior art, the present invention has the following advantages and technical effects:

[0038] (1) In the nickel-based electrode for hydrogen evolution reaction of alkaline electrolyzed water of the present invention, Pt single atoms are anchored on MoO x nanoclusters. Compared with the electrode loaded with Pt nanoclusters, it has a higher atomic utilization rate, higher catalytic performance of the active center Pt, lower intermediate adsorption energy barrier, and the catalyst can carry out reversible catalytic reactions in alkaline electrolytes. The present invention uses single-atom Pt and the MoO x anchored thereon as the main active sites, and cooperates with Ni particles for catalysis, having high activity for the adsorption of intermediate reactions, so that the prepared nickel-based electrode has excellent HER performance.

[0039] (2) The nickel-based electrode for hydrogen evolution reaction of alkaline electrolyzed water of the present invention has low preparation cost, can be industrially produced and applied to industrial hydrogen production, has high catalytic activity, stable catalytic performance, and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0041] Figure 1 XRD pattern of Pt1-MoO x NCs / NiNPs / Ni prepared in Example 1;

[0042] Figure 2 XPS pattern of Pt1-MoO x NCs / NiNPs / Ni prepared in Example 1;

[0043] Figure 3 SEM image of Pt1-MoO x NCs / NiNPs / Ni prepared in Example 1 at a scale of 400 μm;

[0044] Figure 4 SEM image of Pt1-MoO x NCs / NiNPs / Ni prepared in Example 1 at a scale of 200 μm;

[0045] Figure 5 SEM image of Pt1-MoO x NCs / NiNPs / Ni prepared in Example 1 at a scale of 40 μm;

[0046] Figure 6 AC-TEM image of Pt1-MoO x NCs / NiNPs / Ni prepared in Example 1;

[0047] Figure 7 Pt1-MoO prepared for Example 1 x HER performance diagram of NCs / NiNPs / Ni;

[0048] Figure 8 Pt1-MoO prepared for Example 1 x NCs / NiNPs / Ni at 1 A·cm -2 Stability test results under. Detailed implementation manners

[0049] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation manners of the present invention.

[0050] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0051] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0052] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the specification of the present invention, which are obvious to those skilled in the art. Other implementation manners obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0053] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0054] An embodiment of the present invention provides a nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water. The electrode has a multi-level structure of single atoms - nanoclusters - nanoparticles - support. The multi-level structure uses a metal nickel (Ni) mesh as the support, and nickel (Ni) is loaded on the metal Ni mesh in the form of particles. Molybdenum oxide (MoO x ) is dispersed on the Ni particles in the form of clusters, and platinum (Pt) is anchored on the MoO x clusters in the form of single atoms.

[0055] In a preferred embodiment of the present invention, the loading amount of Pt accounts for 0.05 - 0.20% of the total mass of the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, preferably 0.05 - 0.185%.

[0056] An embodiment of the present invention also provides a preparation method of the above-mentioned nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water. The nickel particles are loaded on the metal nickel mesh by plasma spraying method, and molybdenum oxide clusters are generated on the nickel particles by heat annealing treatment. Then, platinum single atoms are loaded on the molybdenum oxide clusters by electrodeposition method to obtain the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, including the following steps:

[0057] (1) Mix nickel-molybdenum alloy powder and aluminum powder and dry them, and then spray them on the metal nickel mesh polished with emery by plasma spraying method;

[0058] (2) Etch the sprayed metal nickel mesh after heat annealing treatment, and then wash and dry it;

[0059] (3) Prepare an electrodeposition solution by mixing sodium hypophosphite and chloroplatinic acid aqueous solution. Use the metal nickel mesh dried in step (2) as the cathode and the platinum sheet electrode as the anode for electrodeposition. After the electrodeposition is completed, take out the cathode, wash it, and obtain the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water.

[0060] In a preferred embodiment step (1) of the present invention, the mass ratio of the nickel-molybdenum alloy powder (the mass ratio of nickel to molybdenum in the nickel-molybdenum alloy powder is 8:1) to the aluminum powder is (2 - 15):1; and / or,

[0061] The drying temperature is 30 - 80 °C and the time is 30 min; and / or,

[0062] The mesh number of the metal nickel mesh is 10 - 80 mesh, and the wire diameter is 0.15 - 2.00 mm.

[0063] In a preferred embodiment step (1) of the present invention, the plasma spraying method is carried out in an inert atmosphere and / or a reducing atmosphere, and the powder feeding amount is 100 - 400 g·m -2 .

[0064] In step (2) of the preferred embodiment of the present invention, the temperature of the thermal annealing treatment is 150-500 °C, and the time is 1-24 h; and / or,

[0065] The etching is carried out with a KOH solution with a mass fraction of 10%-30% for 10-20 h.

[0066] In step (3) of the preferred embodiment of the present invention, the dosage ratio of sodium hypophosphite and chloroplatinic acid aqueous solution is (3-8) g:(1-1000) μL, and the concentration of the chloroplatinic acid aqueous solution is 10-20 mg / mL; and / or,

[0067] The current of the electrodeposition is 5-100 mA, and the treatment time is 1-20 h.

[0068] In the preferred embodiment of the present invention, both the plasma spraying method and the thermal annealing treatment are carried out in an inert atmosphere and / or a reducing atmosphere. The inert atmosphere is selected from nitrogen and argon, and the reducing atmosphere is selected from hydrogen and CO.

[0069] More specifically, the preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction includes the following steps:

[0070] (1) Mix nickel-molybdenum alloy powder (the mass ratio of nickel to molybdenum is 8:1) and aluminum powder according to a mass ratio of (2-15):1, mix them with a mixer for 20-60 min, then put them into an oven, dry them at 30-80 °C for 30 min, take them out and evenly spray them on a metal nickel mesh polished with emery by a plasma spraying machine. Set the powder feeding amount of the plasma spraying machine to 100-400 g·m -2 , the mesh number of the metal nickel mesh is 10-80 meshes, and the wire diameter is 0.15-2.00 mm;

[0071] (2) Place the sprayed metal nickel mesh in a tube furnace and use an inert (nitrogen, argon), reducing atmosphere (hydrogen, CO) or a reducing and inert mixed atmosphere to perform thermal annealing treatment at 150-500 °C for 1-24 h, then etch it with a KOH solution with a mass fraction of 10%-30% for 10-20 h, and then wash it with deionized water until the washing liquid is neutral. Then wash the etched metal nickel mesh with deionized water, absolute ethanol, and acetone in sequence and dry it for standby. The drying process can be oven drying or vacuum drying, and there is no specific requirement;

[0072] (3) Put (3 - 8) g of sodium hypophosphite (NaH₂PO₂) and (1 - 1000) μL of an aqueous solution of chloroplatinic acid with a concentration of 10 - 20 mg / mL into a beaker, add deionized water to make up the volume to 60 mL to prepare an electrodeposition solution. Take the dried nickel mesh in step (2) as the cathode (2×2 cm), and a platinum sheet electrode as the anode. Use a blue electrochemical workstation to set a constant current charge of 5 - 100 mA for 1 - 20 h for constant current electrodeposition. After the electrodeposition is completed, rinse it clean with deionized water and absolute ethanol to obtain the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction, denoted as Pt1-MoO x NCs / NiNPs / Ni.

[0073] In the embodiments of the present invention, the plasma spraying method, thermal annealing treatment, and electrodeposition method are all conventional technical means in the art. The specific steps of the above operation process are not the inventive points of the present invention. Instead, through the coordinated setting of various parameters in the plasma spraying method, thermal annealing treatment, and electrodeposition method, a nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction is successfully prepared.

[0074] All raw materials used in the embodiments of the present invention are commercially available. Among them, sodium hypophosphite is NaH₂PO₂·H₂O, with a MW of 105.99 (87.98 anhydrous); chloroplatinic acid is H₂PtCl₄·6H₂O, with a MW of 517.92, and the content (calculated as Pt) is not less than 38.5%; the content of nitrate (NO₃) is 0.04%, and the content of nitric acid soluble substances is 0.2%.

[0075] The technical solutions of the present invention will be further described below through examples.

[0076] Example 1

[0077] A nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction, the preparation method is as follows:

[0078] (1) Mix 800 g of commercial nickel-molybdenum alloy powder (the mass ratio of nickel to molybdenum is 8:1) and 200 g of commercial aluminum powder, mix them with a mixer for 30 min, then put them into an oven, dry at 80 °C for 30 min, take them out and evenly spray them on a nickel mesh polished with emery paper using a plasma spraying machine. Set the powder feeding amount of the plasma spraying machine to 300 g·m -2 , the mesh number of the nickel mesh is 46, and the wire diameter is 0.25 mm;

[0079] (2) Put the sprayed nickel mesh into a tubular furnace and perform thermal annealing treatment at 500 °C for 2 h under an inert argon atmosphere. After the thermal annealing treatment, cut the nickel mesh into 2×2 cm flakes, etch them batch by batch with a 30% mass fraction KOH solution for 20 h, then wash them with deionized water until the washing liquid is neutral, and successively wash the etched nickel mesh with deionized water, absolute ethanol, and acetone, and then dry it.

[0080] (3) Put 4 g of sodium hypophosphite and 260 μL of an aqueous solution of chloroplatinic acid with a concentration of 10 mg / mL into a beaker, add deionized water to make up the volume to 60 mL to prepare an electrodeposition solution. Take the dried nickel mesh in step (2) as the cathode and the platinum sheet electrode as the anode, and use the Blue Electric Battery Test System to set a constant current charge of 10 mA for 20 h for constant current electrodeposition. After the electrodeposition is completed, rinse it thoroughly with deionized water and absolute ethanol to obtain a nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, denoted as Pt1-MoO x NCs / NiNPs / Ni.

[0081] Example 2

[0082] A nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, the preparation method is the same as that of Example 1, the only difference is that the amount of the aqueous solution of chloroplatinic acid is 520 μL.

[0083] Example 3

[0084] A nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, the preparation method is the same as that of Example 1, the only difference is that the powder feeding amount of the plasma spraying machine is set to 100 g·m -2 .

[0085] Example 4

[0086] A nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, the preparation method is the same as that of Example 1, the only difference is that the amount of sodium hypophosphite is 8 g.

[0087] Example 5

[0088] A nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, the preparation method is the same as that of Example 1, the only difference is that the concentration of the aqueous solution of chloroplatinic acid is 20 mg / mL, and the Blue Electric Battery Test System is used to set a constant current charge of 100 mA for 1 h for constant current electrodeposition.

[0089] Comparative Example 1

[0090] A nickel-based electrode, the preparation method is the same as that of Example 1, the only difference is that the step of heat annealing treatment is omitted, specifically:

[0091] (1) Mix 800 g of commercial nickel-molybdenum alloy powder (mass ratio of nickel to molybdenum is 8:1) and 200 g of commercial aluminum powder, mix them with a mixer for 30 min, then put them into an oven, dry them at 80 °C for 30 min, take them out and spray them evenly on the nickel mesh polished with emery by a plasma spraying machine, set the powder feeding amount of the plasma spraying machine to 300 g·m -2 , the mesh number of the nickel mesh is 46, and the wire diameter is 0.25 mm;

[0092] (2) Cut the sprayed nickel metal mesh into 2×2 cm flakes, and etch them in batches with 30% KOH solution by mass for 20 h. Then wash with deionized water until the washing liquid is neutral, and successively wash the etched nickel metal mesh with deionized water, absolute ethanol, and acetone, and dry it.

[0093] (3) Put 4 g of sodium hypophosphite and 260 μL of an aqueous solution of chloroplatinic acid with a concentration of 10 mg / mL into a beaker, add deionized water to make up the volume to 60 mL to prepare an electrodeposition solution. Take the nickel metal mesh dried in step (2) as the cathode and the platinum plate electrode as the anode, and use the Blue Electric Battery Test System to set a constant current charge of 10 mA for 20 h for constant current electrodeposition. After the electrodeposition is completed, rinse it with deionized water and absolute ethanol to obtain a nickel-based electrode.

[0094] Comparative Example 2

[0095] A nickel-based electrode, the preparation method is the same as that in Example 1, the difference is only that the commercial nickel-molybdenum alloy powder is replaced with an equal mass of commercial nickel powder, specifically:

[0096] (1) Mix 800 g of commercial nickel powder and 200 g of commercial aluminum powder, mix them with a mixer for 30 min, then put them into an oven and dry at 80 °C for 30 min. After taking them out, spray them evenly on the nickel metal mesh polished with emery by a plasma spraying machine, and set the powder feeding amount of the plasma spraying machine to 300 g·m -2 , the mesh number of the nickel metal mesh is 46, and the wire diameter is 0.25 mm;

[0097] (2) Place the sprayed nickel metal mesh in a tubular furnace and perform heat annealing treatment at 500 °C for 2 h under an inert argon atmosphere. After the heat annealing treatment, cut the nickel metal mesh into 2×2 cm flakes, and etch them in batches with 30% KOH solution by mass for 20 h. Then wash with deionized water until the washing liquid is neutral, and successively wash the etched nickel metal mesh with deionized water, absolute ethanol, and acetone, and dry it.

[0098] (3) Put 4 g of sodium hypophosphite and 260 μL of an aqueous solution of chloroplatinic acid with a concentration of 10 mg / mL into a beaker, add deionized water to make up the volume to 60 mL to prepare an electrodeposition solution. Take the nickel metal mesh dried in step (the second) as the cathode and the platinum plate electrode as the anode, and use the Blue Electric Battery Test System to set a constant current charge of 10 mA for 20 h for constant current electrodeposition. After the electrodeposition is completed, rinse it with deionized water and absolute ethanol to obtain a nickel-based electrode.

[0099] Comparative Example 3

[0100] Commercial Raney nickel electrode.

[0101] Comparative Example 4

[0102] Commercial foamed nickel electrode.

[0103] Comparative Example 5

[0104] A nickel-based electrode was prepared in the same manner as in Example 1, except that the electro-deposition step was omitted, specifically:

[0105] (1) 800 g of commercial nickel-molybdenum alloy powder (mass ratio of nickel to molybdenum is 8:1) and 200 g of commercial aluminum powder were mixed and then mixed by a mixer for 30 min, and then placed in an oven and dried at 80 °C for 30 min. After taking out, it was evenly sprayed on a metal nickel mesh polished with emery by a plasma spraying machine. The powder feeding amount of the plasma spraying machine was set to 300 g·m -2 , the mesh number of the metal nickel mesh was 46 meshes, and the wire diameter was 0.25 mm;

[0106] (2) The sprayed metal nickel mesh was heat-annealed in a tubular furnace under an inert argon atmosphere at 500 °C for 2 h. After the heat-annealing treatment, the metal nickel mesh was cut into 2×2 cm flakes, and etched in batches with a 30% by mass KOH solution for 20 h, and then washed with deionized water until the washing liquid was neutral, and the etched metal nickel mesh was washed clean and dried successively with deionized water, absolute ethanol, and acetone to obtain the nickel-based electrode.

[0107] Example 6

[0108] A nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction was prepared as follows:

[0109] (1) 400 g of commercial nickel-molybdenum alloy powder (mass ratio of nickel to molybdenum is 8:1) and 200 g of commercial aluminum powder were mixed and then mixed by a mixer for 60 min, and then placed in an oven and dried at 50 °C for 30 min. After taking out, it was evenly sprayed on a metal nickel mesh polished with emery by a plasma spraying machine. The powder feeding amount of the plasma spraying machine was set to 400 g·m -2 , the mesh number of the metal nickel mesh was 80 meshes, and the wire diameter was 0.15 mm;

[0110] (2) The sprayed metal nickel mesh was heat-annealed in a tubular furnace under a hydrogen atmosphere at 150 °C for 24 h. After the heat-annealing treatment, the metal nickel mesh was cut into 2×2 cm flakes, and etched in batches with a 10% by mass KOH solution for 15 h, and then washed with deionized water until the washing liquid was neutral, and the etched metal nickel mesh was washed clean and dried successively with deionized water, absolute ethanol, and acetone;

[0111] (3) Put 3 g of sodium hypophosphite and 1000 μL of an aqueous solution of chloroplatinic acid with a concentration of 10 mg / mL into a beaker, add deionized water to make up the volume to 60 mL to prepare an electrodeposition solution. Take the dried nickel mesh obtained in step (2) as the cathode and the platinum plate electrode as the anode, and use the Blue Electrochemical Cell Test System to set a constant current charge of 100 mA for 1 h for constant current electrodeposition. After the electrodeposition is completed, rinse it thoroughly with deionized water and absolute ethanol to obtain a nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water.

[0112] Example 7

[0113] A nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water, and the preparation method is as follows:

[0114] (1) Mix 3000 g of commercial nickel-molybdenum alloy powder (the mass ratio of nickel to molybdenum is 8:1) and 200 g of commercial aluminum powder, mix them with a mixer for 20 min, then put them into an oven, dry them at 30 °C for 30 min, take them out and evenly spray them on a nickel mesh polished with emery using a plasma spraying machine. Set the powder feeding amount of the plasma spraying machine to 100 g·m -2 , the mesh number of the nickel mesh is 10 mesh, and the wire diameter is 2.00 mm;

[0115] (2) Use an argon atmosphere in a tubular furnace to perform thermal annealing treatment on the sprayed nickel mesh at 500 °C for 1 h. After the thermal annealing treatment, cut the nickel mesh into 2×2 cm flakes, etch them in batches with a 20% mass fraction of KOH solution for 10 h, then wash them with deionized water until the washing liquid is neutral, and wash the etched nickel mesh with deionized water, absolute ethanol, and acetone in sequence and dry it.

[0116] (3) Put 8 g of sodium hypophosphite and 1 μL of an aqueous solution of chloroplatinic acid with a concentration of 10 mg / mL into a beaker, add deionized water to make up the volume to 60 mL to prepare an electrodeposition solution. Take the dried nickel mesh obtained in step (2) as the cathode and the platinum plate electrode as the anode, and use the Blue Electrochemical Cell Test System to set a constant current charge of 5 mA for 20 h for constant current electrodeposition. After the electrodeposition is completed, rinse it thoroughly with deionized water and absolute ethanol to obtain a nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water.

[0117] Performance Test

[0118] The XRD pattern of Pt1-MoO x NCs / NiNPs / Ni prepared in Example 1 is shown in Figure 1 , the XPS pattern is shown in Figure 2 , the SEM image at a scale of 400 μm is shown in Figure 3 , the SEM image at a scale of 200 μm is shown in Figure 4 , the SEM image at a scale of 40 μm is shown in Figure 5 , the AC-TEM image is shown in Figure 6, see the HER performance graph in Figure 7 , for the alkaline hydrogen evolution reaction of the two - electrode system (the anode is a commercial Raney nickel electrode), Pt1 - MoO x NCs / NiNPs / Ni at 1 A·cm -2 The stability test results are shown in Figure 8 .

[0119] According to Figures 1-8 , it can be seen that the Pt1 - MoO x NCs / NiNPs / Ni electrode prepared in Example 1 of the present invention has a large specific surface area, which can provide more catalytic sites, thereby improving the electro - catalytic activity of HER. Among them, MoO x clusters are highly dispersed on Ni particles, and the synergistic effect with Ni particles can regulate the electron cloud density between atoms, increase the transfer energy barrier between electrons. Pt single atoms are loaded on MoO x nanoclusters, which can provide the maximum atomic utilization rate of Pt in theory, and through the coordination effect with MoO x nanoclusters and Ni particles, adjust the adsorption free energy of intermediates, thereby reducing the reaction energy consumption. Pt is loaded on MoO x nanoclusters in the form of single atoms. Compared with Pt in the form of clusters or relatively dispersed Pt particles, the Pt in the form of clusters or relatively dispersed Pt particles has a low atomic utilization rate and a large Pt size, blocking some active sites and reducing the adsorption amount of intermediates during the reaction. Further, combined with the scanning electron microscope (SEM image) and transmission electron microscope (TEM image) analysis of the catalyst on the surface of the Pt1 - MoO x NCs / NiNPs / Ni electrode prepared in Example 1, it can be known that the electro - catalytic activity of the electrode during the HER reaction is related to the dispersion degree of the catalyst on the electrode surface, and high dispersion has a positive promoting effect on the catalytic activity. Since in electrodes with only non - noble metals, there is a lack of specific adsorption ability for intermediate products, the present invention selects the noble metal Pt to adjust the adsorption energy barrier of the intermediate H*. Only the diffraction peaks of Ni and Mo are observed in the X - ray diffraction pattern (XRD pattern) of the catalyst on the electrode surface. The reason for the small deviation from the standard card is the interaction force between Pt atoms and Ni, Mo atoms. At the same time, no relevant diffraction peaks of Pt are found, indicating that Pt atoms are highly dispersed. Considering the detection limit of X - ray diffraction peaks, small - size clusters cannot be detected for diffraction peaks, and spherical aberration - corrected transmission electron microscopy (AC - TEM) tests were carried out on them, and it was observed that Pt exists in the form of single atoms. From the X - ray photoelectron spectroscopy (XPS spectrum), it is found that the absorption peak of the 4f electrons of Pt atoms indicates that Pt atoms are successfully doped onto the electrode surface and play a role in catalyzing the HER reaction.

[0120] The electrodes prepared in the above examples and comparative examples were subjected to performance tests. Specifically: it was carried out in a standard three - electrode system, with a platinum sheet as the counter electrode, a saturated calomel electrode (SCE) as the reference electrode, and the electrode prepared in the example or comparative example as the working electrode. The electrolyte was KOH with a concentration of 1 M. All data were calibrated to the potential relative to the standard hydrogen electrode (RHE), and IR correction was performed on the electrolyte.

[0121] The calibration formula is:

[0122] E (RHE) = E (SCE) + 0.0591*pH + 0.24 - 0.95*I*R;

[0123] In the formula, E (RHE) represents the standard electrode potential of the standard hydrogen electrode, E (SEC) represents the standard electrode potential of the saturated calomel electrode, I represents the current density, with the unit of Acm -2 , and R is the solution resistance.

[0124] The performance indexes of the electrodes prepared in the examples and comparative examples are shown in Table 1.

[0125] Table 1 Performance indexes of each electrode

[0126]

[0127] In each example and comparative example of the present invention, the loading amount of the noble metal Pt was obtained by testing with an inductively coupled plasma emission spectrometer. The preparation method of the test sample was: taking 5 mg of the electrode, dissolving it in 1 mL of aqua regia at 40 °C until it was completely dissolved, then diluting it with water to 10 mL and filtering. The obtained solution was the test sample.

[0128] The doping of the noble metal Pt will make the catalyst have higher catalytic activity. It can be seen from Table 1 that among the performances corresponding to different Pt loading amounts, it is not that the more the loading amount of the noble metal Pt, the better the performance. The doping amount in the form of single atoms will make the utilization rate of metal atoms reach the highest. In the analysis of the electrode performance with different Pt loading amounts, a larger Pt doping amount does not show excellent performance. It may be because too much noble metal occupies the active sites of the reaction, increasing the adsorption free energy of the intermediate, so that the intermediate product cannot enter the active sites on the electrode surface. This is a common problem in supported catalysts.

[0129] The present invention prepared an alkaline HER electrode with a hierarchical structure by using Pt single atoms, MoO x nanoclusters, Ni particles, and a support Ni mesh, and for the first time explained the mechanism of the alkaline hydrogen evolution reaction (HER) from the microscale to the macroscale and prepared a hydrogen evolution reaction electrode with a hierarchical structure starting from the micro - reaction mechanism.

[0130] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction, characterized in that, The nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water has a multi-level structure of single atoms - nanoclusters - nanoparticles - support. The multi-level structure uses a metal nickel mesh as the support, nickel is loaded on the metal nickel mesh in the form of particles, molybdenum oxide is dispersed on the nickel particles in the form of clusters, and platinum is anchored on the molybdenum oxide clusters in the form of single atoms.

2. The nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water according to claim 1, characterized in that, The loading amount of platinum accounts for 0.05 - 0.20% of the total mass of the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water.

3. The preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction according to any one of claims 1 to 2, characterized in that, The nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water is obtained by using the plasma spraying method to load nickel particles on a metal nickel mesh, generating molybdenum oxide clusters on the nickel particles through heat annealing treatment, and then using the electrodeposition method to load platinum single atoms on the molybdenum oxide clusters.

4. The preparation method of the nickel-based electrode for the hydrogen evolution reaction of alkaline electrolyzed water according to claim 3, wherein, It includes the following steps: (1) Mix nickel-molybdenum alloy powder and aluminum powder and dry them, and then spray them on a metal nickel mesh by the plasma spraying method; (2) Etch the sprayed metal nickel mesh after heat annealing treatment, and then wash and dry it; (3) Prepare an electrodeposition solution by mixing sodium hypophosphite and chloroplatinic acid aqueous solution. Use the metal nickel mesh dried in step (2) as the cathode and a platinum sheet electrode as the anode for electrodeposition. After the electrodeposition is completed, take out the cathode and wash it to obtain the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water.

5. The preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction according to claim 4, characterized in that, In step (1), the mass ratio of the nickel-molybdenum alloy powder to the aluminum powder is (2 - 15)∶1; and / or, The drying temperature is 30 - 80 °C and the time is 30 min; and / or, The mesh number of the metal nickel mesh is 10 - 80 mesh and the wire diameter is 0.15 - 2.00 mm.

6. The preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction according to claim 4, characterized in that, In step (1), the plasma spraying method is carried out in an inert atmosphere and / or a reducing atmosphere, and the powder feeding amount is 100-400 g·m -2 .

7. The preparation method of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction according to claim 4, characterized in that, In step (2), the temperature of the heat annealing treatment is 150 - 500 °C and the time is 1 - 24 h; and / or, The etching is carried out with a KOH solution with a mass fraction of 10% - 30% for 10 - 20 h.

8. The preparation method of the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water according to claim 4, characterized in that, In step (3), the dosage ratio of sodium hypophosphite to chloroplatinic acid aqueous solution is (3 - 8) g∶(1 - 1000) μL, and the concentration of the chloroplatinic acid aqueous solution is 10 - 20 mg / mL; and / or, The current of the electrodeposition is 5 - 100 mA and the treatment time is 1 - 20 h.

9. Application of the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water according to any one of claims 1 - 2 in hydrogen production by electrolyzing water.

10. Use of the nickel-based electrode for alkaline electrolytic water hydrogen evolution reaction according to claim 9 in electrolytic water hydrogen production, characterized in that, Using the nickel-based electrode for hydrogen evolution reaction in alkaline electrolyzed water as the working electrode.

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