Rare earth element samarium doped ruthenium oxide and preparation method and application thereof

Abstract

The invention belongs to the technical field of catalytic materials, and discloses rare earth element samarium-doped ruthenium oxide and a preparation method and application thereof.The method comprises the steps that glucose and urea are dissolved in water to obtain a first solution; adding RuCl3 and SmCl3 into the first solution, and uniformly mixing to obtain a second solution; heating the second solution to obtain a gel solid precursor, and grinding the gel solid precursor into fine powder; placing the gel solid precursor powder in air, heating the gel solid precursor powder to a preset temperature, and preserving the temperature of a cold area to room temperature to obtain samarium-doped ruthenium oxide. The samarium-doped ruthenium oxide is prepared through a sol-gel method, samarium doping not only reduces the loading amount of precious metal, but also improves the activity and stability of the ruthenium oxide in acidic OER, and the rare earth element samarium-doped ruthenium oxide improves the electronic structure of the material, stabilizes active sites and synergistically improves the electrocatalytic activity and stability of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic materials, and in particular to ruthenium oxide doped with the rare earth element samarium, and a preparation method and application thereof. Background Art

[0002] As the world's dependence on energy continues to deepen and awareness of environmental protection grows, the energy crisis and environmental pollution caused by the large-scale extraction and use of traditional fossil fuels are becoming increasingly prominent. Against this backdrop, the search for clean, renewable energy alternatives has become an inevitable trend in global energy development to achieve coordinated development of the economy, society, and the environment.

[0003] Among the many renewable energy options, hydrogen is widely recognized as an ideal alternative to traditional fossil fuels due to its superior energy density and the fact that it produces only water upon combustion, with no pollutant emissions. As an efficient and environmentally friendly method for hydrogen production, water electrolysis can produce pure hydrogen at room temperature and pressure without generating carbon dioxide emissions. Currently, acidic proton exchange membrane water electrolyzers (PEMWEs) are attracting significant attention in the field of water electrolysis hydrogen production due to their advantages, including higher operating current density, faster response rate, and lower ohmic conductance.

[0004] However, during the hydrogen production process of PEMWE, the environment in which the anode is located is extremely corrosive (pH: 0-3) and strongly oxidizing, which poses a severe challenge to the oxygen evolution reaction (OER) catalyst at the anode. The precious metal iridium oxide (IrO2) and ruthenium oxide (RuO2) are recognized as benchmark electrocatalysts in acidic OER reactions due to their excellent catalytic efficiency, stability and corrosion resistance. Compared with IrO2, RuO2 has higher intrinsic activity and is considered to be the most promising material to replace commercial IrO2. However, during the OER process, RuO2 will undergo over-oxidation to produce dissolved high-valent ruthenium ions, causing the crystal structure of the catalyst to gradually collapse, resulting in instability of PEMWE.

[0005] Therefore, how to effectively improve the stability and activity of RuO2 is a key problem to be solved in order to promote the commercial application of PEMWE technology and the sustainable development of the hydrogen energy industry. Summary of the Invention

[0006] The embodiments of the present invention provide a rare earth element samarium-doped ruthenium oxide and a preparation method and application thereof to solve the above-mentioned technical problems in the prior art.

[0007] To provide a basic understanding of some aspects of the disclosed embodiments, the following is a brief summary. This summary is not intended to be a comprehensive review, identify key or essential elements, or delineate the scope of these embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the detailed description that follows.

[0008] According to a first aspect of an embodiment of the present invention, a method for preparing ruthenium oxide doped with the rare earth element samarium is provided.

[0009] In one embodiment, the method for preparing the rare earth element samarium-doped ruthenium oxide comprises:

[0010] Dissolving glucose and urea in water based on a predetermined ratio to obtain a first solution;

[0011] Adding RuCl3 and SmCl3 to the first solution and mixing them uniformly to obtain a second solution;

[0012] heating the second solution to obtain a gel solid precursor, and grinding the gel solid precursor into fine powder;

[0013] The gel solid precursor powder is placed in air and heated to a predetermined temperature, and then cooled to room temperature to obtain samarium-doped ruthenium oxide.

[0014] In one embodiment, the glucose is dissolved in water at a ratio of 0.88-1.12 g / ml, and the urea is dissolved in water at a ratio of 0.14-0.26 g / ml.

[0015] In one embodiment, the mass ratio of glucose to urea is (4-6 g):(0.8-1.2 g).

[0016] In one embodiment, the amount of SmCl 3 added is less than or equal to 28 mol % of RuCl 3 .

[0017] In one embodiment, the mass ratio of the sum of the added amounts of RuCl 3 and SmCl 3 to the mass ratio of the glucose in the first solution is (38-52 mg): (4.4-5.6 g).

[0018] In one embodiment, the mass ratio of the sum of the added amounts of RuCl 3 and SmCl 3 to the mass ratio of the glucose in the first solution is (35-55 mg): (4-6 g).

[0019] In one embodiment, the mixing time after adding RuCl 3 and SmCl 3 to the first solution is 55-65 minutes.

[0020] In one embodiment, the second solution is heated at a temperature of 134-146° C. for a heating time of 4-6 hours.

[0021] In one embodiment, the second solution is heated at a temperature of 134-146° C. for a heating time of 4.5-5.5 hours.

[0022] In one embodiment, the second solution is heated at a temperature of 135-145° C. for a heating time of 4.6-5.4 hours.

[0023] In one embodiment, grinding of the solid precursor to the gel is performed in an agate mortar.

[0024] In one embodiment, the gel solid precursor powder is heated in air at a heating rate of 2-4° C. / min, a predetermined temperature of 470-530° C., and a holding time of 7.5-8.5 h.

[0025] In one embodiment, the gel solid precursor powder is heated in air at a heating rate of 2-4° C. / min, a predetermined temperature of 480-520° C., and a holding time of 7.5-8.5 h.

[0026] In one embodiment, the gel solid precursor powder is heated in air at a heating rate of 2-4° C. / min, a predetermined temperature of 485-515° C., and a holding time of 7.5-8.5 h.

[0027] According to a second aspect of an embodiment of the present invention, there is provided ruthenium oxide doped with the rare earth element samarium.

[0028] In one embodiment, the rare earth element samarium-doped ruthenium oxide is prepared using the above-mentioned method for preparing rare earth element samarium-doped ruthenium oxide, and the molar percentage of the rare earth element samarium relative to the ruthenium element in the rare earth element samarium-doped ruthenium oxide is less than or equal to 28 mol%.

[0029] According to a third aspect of an embodiment of the present invention, there is provided a rare earth element samarium-doped ruthenium oxide prepared by the above-mentioned preparation method of rare earth element samarium-doped ruthenium oxide or the use of the above-mentioned rare earth element samarium-doped ruthenium oxide in an acidic electrocatalytic oxygen evolution reaction.

[0030] The technical solution provided by the embodiment of the present invention may have the following beneficial effects:

[0031] 1) This invention prepares samarium-doped ruthenium oxide via a sol-gel method. Samarium doping not only reduces the noble metal loading but also improves its activity and stability in acidic OER. Doping ruthenium oxide with the rare earth element samarium improves the material's electronic structure, stabilizes active sites, and synergistically enhances its electrocatalytic activity and stability.

[0032] 2) The present invention prepares samarium-doped ruthenium oxide with different proportions by gel method and subsequent calcination. The samarium-doped ruthenium oxide exhibits excellent catalytic activity in the acidic OER process. When the current density reaches 10 mA / cm 2 The OER overpotential is only 219 mV.

[0033] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0035] Figure 1 is a SEM image of RuO2 in Example 1;

[0036] Figure 2 is the SEM image of Sm-20 in Example 4;

[0037] Figure 3 The XRD diffraction patterns of the materials of Example 1 (RuO2), Example 2 (Sm-5), Example 3 (Sm-10), Example 4 (Sm-20), and Example 5 (Sm-25) are compared with the standard cards;

[0038] Figure 4 These are the OER polarization curves of the materials of Example 1 (RuO2), Example 2 (Sm-5), Example 3 (Sm-10), Example 4 (Sm-20), and Example 5 (Sm-25). DETAILED DESCRIPTION

[0039] The following description and accompanying drawings sufficiently illustrate the specific embodiments herein to enable those skilled in the art to practice them. Portions and features of some embodiments may be included in or substituted for portions and features of other embodiments. The scope of the embodiments herein includes the entire scope of the claims, including all available equivalents thereof. Herein, the terms "first," "second," and the like are used solely to distinguish one element from another and do not require or imply any actual relationship or order between these elements. In practice, the first element can also be referred to as the second element, and vice versa. Furthermore, the terms "comprise," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a structure, device, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such structure, device, or apparatus. Without further limitation, an element defined by the phrase "comprising a..." does not preclude the presence of other identical elements in the structure, device, or apparatus comprising the element. The various embodiments herein are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Similar or identical parts between the various embodiments can be referenced to each other.

[0040] The terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used herein to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are intended only to facilitate the description of this document and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In the description herein, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, they can be mechanical or electrical connections, or they can be internal connections between two elements, they can be directly connected, or they can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0041] As used herein, unless otherwise specified, the term "plurality" means two or more.

[0042] In this document, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0043] In this article, the term "and / or" is used to describe the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0044] It should be understood that, although the various steps in the flowchart are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps may be performed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but may be performed at different times. The execution order of these sub-steps or stages is not necessarily to be performed in sequence, but may be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0045] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0046] Notes on relevant elements in the embodiment:

[0047] Ruthenium is a hard, brittle, light gray, multivalent rare metal with the symbol Ru and atomic number 44. It is located in Group VIII of the fifth period and belongs to the d-block metals. Ruthenium is a member of the platinum group metals and is present in the Earth's crust at only one billionth of its concentration, making it one of the rarest metals. Ruthenium has a hexagonal crystal structure, a melting point of 2334°C, a boiling point of 4150°C, and a density of 12.45 g / cm at room temperature. 3 , the atomic radius is 133 pm, and the first ionization energy is 710.2 kJ·mol -1 It is very stable and corrosion-resistant, withstanding corrosion from hydrochloric acid, sulfuric acid, nitric acid, and aqua regia at room temperature. Ruthenium is the cheapest of the platinum group metals, although other metals such as platinum and palladium are more abundant. Ruthenium is widely used in electronics, medicine, electrochemistry, and other fields. Ruthenium and its complexes exhibit excellent catalytic activity and can be used as catalysts in a variety of chemical reactions.

[0048] Samarium is a typical rare earth metal with the chemical symbol Sm. It is a silvery-white metal with medium hardness and is easily oxidized in air. Samarium is usually trivalent.

[0049] Iridium, a metallic element with the symbol Ir, atomic number 77, and atomic weight 192.22, is named after the Latin word for "rainbow." Iridium is present in the Earth's crust at a concentration of one part per ten million. It is often found alongside platinum-group elements in various ores found in alluvial and placer deposits.

[0050] Notes on related compounds and molecular weights in the examples:

[0051] Glucose, whose chemical formula is C6H 12 O6, molecular weight is 180.16.

[0052] Urea, also known as carbamide or urea, has a chemical formula of CH₄N₂O or CO(NH₂)₂. It is an organic compound composed of carbon, nitrogen, oxygen, and hydrogen. It is a white crystalline solid. It is one of the simplest organic compounds and the primary nitrogenous end product of protein metabolism in mammals and some fish. Its molecular weight is 60.06.

[0053] RuCl3, also known as ruthenium trichloride, is a chemical substance with a molecular weight of 207.43.

[0054] SmCl3, also known as samarium chloride, is a rare earth compound with a molecular weight of 256.72.

[0055] A method for preparing samarium-doped ruthenium oxide comprises the following steps:

[0056] (1) dissolving glucose in water at a ratio of 0.88-1.12 g / ml and dissolving urea in water at a ratio of 0.14-0.26 g / ml to obtain solution a;

[0057] (2) adding RuCl3 and SmCl3 to solution a, wherein the amount of SmCl3 added is not more than 28 mol% of RuCl3, and the mass ratio of the total amount of RuCl3 and SmCl3 added to the mass of glucose in solution a is (38 mg-52 mg): (4.4 g-5.6 g), and mixing well to obtain solution b;

[0058] (3) treating solution b at 134-146°C for 4-6 hours to form a porous foam-like gel solid precursor;

[0059] (4) grinding the gel solid precursor into a fine powder;

[0060] (5) The fine powder is heated to 470-530°C at a rate of 2-4°C / min in an air atmosphere, kept at this temperature for 7.5-8.5 hours, and cooled to room temperature to obtain samarium-doped ruthenium oxide.

[0061] In some embodiments, in step (1), glucose is dissolved in water at a ratio of 0.88-1.12 g / ml, and urea is dissolved in water at a ratio of 0.14-0.26 g / ml to obtain solution a.

[0062] Among them, the decomposition products of urea and glucose form a gel network through condensation reaction. Glucose acts as a structure-directing agent and forms a specific coordination structure with the metal ions in RuCl3 and SmCl3. A reduced amount of glucose cannot fully coordinate with the metal ions, affecting the structure; an increased amount of glucose may cause the gel solid precursor to remain after calcination, affecting the performance of the catalyst. Urea decomposes at around 140 degrees Celsius to produce gases (ammonia and carbon dioxide), which act as a foaming agent to help form a porous structure. Too much urea will produce too much gas in the gel to form larger pores, leading to defects and unevenness on the catalyst; too low a content is not enough to form enough bubbles, and the gel is not completely gelled. The gel network further undergoes thermal decomposition, and the organic components are burned off, leaving behind metal oxides. Through research, the inventors have optimized the mass ratio of glucose to urea to be (4-6g): (0.8-1.2g).

[0063] In some of the embodiments, the amount of SmCl 3 added is not more than 28 mol % of RuCl 3 .

[0064] The SmCl3 addition level ranges from 0 to 28 mol%, selected based on the catalytic performance of the acidic OER. Too much or too little SmCl3 can affect the performance of the acidic OER. Excessive Sm doping can lead to overoccupancy of catalytic active sites and may also cause lattice distortion, affecting catalyst stability. Too little Sm doping prevents the advantages of Sm's electronic structure optimization, resulting in minimal improvement in catalytic performance.

[0065] In some preferred embodiments, in step (2), RuCl3 and SmCl3 are added to solution a, wherein the mass ratio of the sum of the added amounts of RuCl3 and SmCl3 to the glucose in solution a is (35-55 mg): (4-6 g), and the mixture is mixed uniformly to obtain solution b.

[0066] In some embodiments, the mixing time of step (2) is 55-65 min.

[0067] In some embodiments, step (3) treats solution b at 134-146° C. for 4-6 hours to obtain a gel solid precursor.

[0068] In some embodiments, in step (3), solution b is treated at 135-145° C. for 4.6-5.4 h to obtain a gel solid precursor.

[0069] In some embodiments, in step (5), the fine powder is heated to 470-530° C. at a rate of 2-4° C. / min in an air atmosphere, kept at this temperature for 7.5-8.5 hours, and cooled to room temperature to obtain samarium-doped ruthenium oxide.

[0070] In some embodiments, in step (5), the fine powder is heated to 485-515° C. at a rate of 2-4° C. / min in an air atmosphere, kept at this temperature for 7.5-8.5 h, and cooled to room temperature to obtain samarium-doped ruthenium oxide.

[0071] Lower calcination temperatures result in incomplete combustion of glucose and urea, leaving carbon residue and unformed products, which can affect catalyst purity and activity. Higher calcination temperatures increase product crystallinity and grain size, reducing specific surface area. This alters the pore structure and affects catalytic activity.

[0072] The calcination time determines the degree of combustion of glucose and urea. Too short will lead to incomplete combustion, while too long will lead to excessive sintering and excessive grain growth, reducing the specific surface area and the number of active sites of the catalyst.

[0073] The technical solution of the present invention is simple, highly operable and easy to repeat.

[0074] Those skilled in the art can also scale up the raw materials according to the ratios in the examples to obtain conditions for industrial production.

[0075] The porcelain boats mentioned in the examples, also called combustion boats or combustion boats, are a type of chemical porcelain. The porcelain boats used in the examples are used in conjunction with muffle furnaces for high-temperature calcination. Those skilled in the art can select appropriate equipment and supporting containers for high-temperature calcination as needed.

[0076] A samarium-doped ruthenium oxide, wherein the ruthenium oxide is doped with samarium elements, and the molar percentage of the samarium elements relative to the ruthenium elements is not higher than 28 mol%.

[0077] Doping involves adding impurity elements to a material to alter its physical, chemical, and electronic properties. Doping is widely used in various fields, particularly in nanotechnology, where the addition of different impurity elements can be used to fine-tune the material's performance by manipulating its size, shape, and electronic properties.

[0078] The application scenarios of the samarium-doped ruthenium oxide include use as a catalyst in acidic electrocatalytic oxygen evolution reaction, can be used in proton exchange membrane water electrolyzer to produce hydrogen; metal air battery, etc.

[0079] In order to better understand the above technical solutions of the present invention, they are described below in conjunction with specific embodiments.

[0080] Example 1: Preparation of pure ruthenium oxide material (RuO2)

[0081] A. First, dissolve 5.2 g of glucose and 1.1 g of urea in a beaker containing 5 mL of deionized water and stir evenly to obtain solution a.

[0082] B. Then, 40 mg of anhydrous RuCl3 was added to solution a, and the mixture was stirred for 60 min to obtain a uniform solution b;

[0083] C. Remove the magnet from solution b and place solution b in an oven at 135°C for 5 hours to form a porous foamy gel solid precursor. The sol solid is then ground into a fine powder in an agate mortar.

[0084] D. Place the fine powder ground in step C evenly on a magnetic boat and place it in a muffle furnace. Raise the temperature to 505°C at a rate of 2-4°C / min in an air atmosphere, keep the temperature for 8 hours, cool to room temperature, and grind to obtain ruthenium oxide. Figure 1 This is the SEM image of ruthenium oxide (RuO2) in Example 1.

[0085] Figure 1 a The rough foam structure of ruthenium oxide (RuO2) can be observed, which is beneficial to improving the catalytic activity. Figure 1 b is an enlarged SEM image, from which a rough foam structure composed of compact nanospheres can be observed. The rough foam structure can increase the specific surface area of the catalyst, which is beneficial to the enhancement of the catalyst activity.

[0086] Example 2: Preparation of 10% molar ratio samarium-doped ruthenium oxide material (abbreviated as Sm-10)

[0087] A. First, dissolve 5.2 g of glucose and 1.1 g of urea in a beaker containing 5 mL of deionized water and stir evenly to obtain solution a.

[0088] B. Then, 40 mg of anhydrous RuCl3 and 5.1 mg of SmCl3 were added to solution a, and the mixture was stirred for 60 min to obtain a homogeneous solution b;

[0089] C. Remove the magnet from solution b and place solution b in an oven at 135°C for 5 hours to form a porous foamy gel solid precursor. Grind the sol solid into a fine powder in an agate mortar.

[0090] D. The fine powder ground in step C is evenly placed in a magnetic boat and placed in a muffle furnace. The temperature is raised to 505°C at a rate of 2-4°C / min in an air atmosphere, kept at this temperature for 8 hours, and cooled to room temperature. After grinding, samarium-doped ruthenium oxide (Sm-5) is obtained.

[0091] Example 3: Preparation of 15% molar ratio samarium-doped ruthenium oxide material (abbreviated as Sm-15)

[0092] A. First, dissolve 5.2 g of glucose and 1.1 g of urea in a beaker containing 5 mL of deionized water and stir evenly to obtain solution a.

[0093] B. Then, 40 mg of anhydrous RuCl3 and 7.7 mg of SmCl3 were added to solution a, and the mixture was stirred for 60 min to obtain a homogeneous solution b;

[0094] C. Remove the magnet from solution b and place solution b in an oven at 135°C for 5 hours to form a porous foamy gel solid precursor. Grind the sol solid into a fine powder in an agate mortar.

[0095] D. Place the fine powder ground in step C evenly on a magnetic boat and place it in a muffle furnace. Raise the temperature to 505°C at a rate of 2-4°C / min in an air atmosphere, keep it warm for 8 hours, cool it to room temperature, and grind it to obtain samarium-doped ruthenium oxide (Sm-15).

[0096] Example 4: Preparation of 20% molar ratio samarium-doped ruthenium oxide material (abbreviated as Sm-20)

[0097] A. First, dissolve 5.2 g of glucose and 1.1 g of urea in a beaker containing 5 mL of deionized water and stir evenly to obtain solution a.

[0098] B. Then, 40 mg of anhydrous RuCl3 and 10.2 mg of SmCl3 were added to solution a, and the mixture was stirred for 60 min to obtain a homogeneous solution b;

[0099] C. Remove the magnet from solution b and place solution b in an oven at 130°C for 5 hours to form a porous foamy gel solid precursor. Grind the sol solid into a fine powder in an agate mortar.

[0100] D. Place the fine powder ground in step C evenly on a magnetic boat and place it in a muffle furnace. Raise the temperature to 505°C at a rate of 2-4°C / min in an air atmosphere, keep it warm for 8 hours, cool it to room temperature, and grind it to obtain samarium-doped ruthenium oxide (Sm-20). Figure 2 This is the SEM image of Sm-20 in Example 4.

[0101] Figure 2 a also observed and Figure 1 a similar rough foam structure, Figure 2 The shape of b is also similar to Figure 1 b Similar in appearance. Figure 1 By comparison, it is shown that the use of samarium to dope ruthenium oxide in the present invention does not change the morphology of ruthenium oxide.

[0102] The samarium-doped ruthenium oxide (Sm-20) prepared in Example 4 has excellent electrocatalytic oxygen evolution performance. 2 The OER overpotential is only 219 mV, which is better than the ruthenium oxide without samarium doping in Example 1 (280 mV).

[0103] Example 5: Preparation of 25% molar ratio samarium-doped ruthenium oxide material (abbreviated as Sm-25)

[0104] A. First, dissolve 5.2 g of glucose and 1.1 g of urea in a beaker containing 5 mL of deionized water and stir evenly to obtain solution a.

[0105] B. Then, 40 mg of anhydrous RuCl3 and 12.8 mg of SmCl3 were added to solution a, and the mixture was stirred for 60 min to obtain a homogeneous solution b;

[0106] C. Remove the magnet from solution b and place solution b in an oven at 135°C for 5 hours to form a porous foamy gel solid precursor. Grind the sol solid into a fine powder in an agate mortar.

[0107] D. Place the fine powder ground in step C evenly on a magnetic boat and place it in a muffle furnace. Raise the temperature to 505°C at a rate of 2-4°C / min in an air atmosphere, keep it warm for 8 hours, cool it to room temperature, and grind it to obtain samarium-doped ruthenium oxide (Sm-25).

[0108] The difference between Example 1 and Example 4 is that no SmCl3 precursor is added to prepare RuO2 nanomaterial. Figure 1 This is the SEM image of RuO2 obtained in Example 1.

[0109] The difference between Example 2 and Example 4 is that the mass of the added SmCl3 precursor is 5.1 mg, and Sm-10 nanomaterial is prepared.

[0110] The difference between Example 3 and Example 4 is that the mass of the added SmCl3 precursor is 7.7 mg, and Sm-15 nanomaterial is prepared.

[0111] The difference between Example 5 and Example 4 is that the mass of the added SmCl3 precursor is 12.8 mg, and Sm-25 nanomaterial is prepared.

[0112] The performance of the samarium-doped ruthenium oxide nanomaterial of this embodiment was analyzed.

[0113] Test Example 1: XRD diffraction analysis

[0114] The samarium-doped ruthenium oxide nanomaterials of Examples 1 to 5 were subjected to XRD diffraction analysis, and the results are shown in FIG. Figure 3 .

[0115] The present invention prepares samarium-doped ruthenium oxide in different proportions by a sol-gel method. Figure 3 The XRD diffraction pattern proved that the preparation was successful. Figure 3In the embodiment, RuO2 represents the ruthenium oxide prepared in Example 1, Sm-

[0116] 10, Sm-15, Sm-20, and Sm-25 represent the samarium-doped ruthenium oxide nanomaterials prepared in Examples 2-5, respectively.

[0117] Figure 3 As shown in FIG, the peak of the XRD spectrum of ruthenium oxide after samarium doping is shifted to a higher angle compared with the ruthenium oxide in Example 1, indicating that the introduction of Sm causes the lattice of ruthenium oxide to shrink.

[0118] Test Example 2: Electrochemical Test

[0119] The nanomaterials prepared in the examples were subjected to electrochemical testing. The electrochemical testing was performed in 0.5 M H₂SO₄ using a three-electrode system on an electrochemical workstation. A glassy carbon electrode (GC), a graphite sheet, and a mercury-mercurous sulfate electrode were used as the working electrode, counter electrode, and reference electrode, respectively. The overpotential (η) was calculated according to the following equation: η = E RHE -1.23V, where E RHE The potential is calibrated to the reversible hydrogen electrode (RHE) standard. Linear sweep voltammetry (LSV) was recorded in 0.5 M H2SO4 solution at a scan rate of 5 mV / s to obtain polarization curves. All electrode potential data were compensated for 95% voltage drop. Figure 4 and Table 1.

[0120] Figure 4 As can be seen from the results, the samarium-doped ruthenium oxide (Sm-20) prepared in Example 4 has excellent electrocatalytic oxygen evolution performance. Figure 4 The OER polarization curve can be observed at a current density of 10 mA / cm 2 The overpotential is only 204 mV, which is better than the ruthenium oxide in Example 1 (277 mV).

[0121] Table 1 Effect of different Sm doping amounts on acidic OER overpotential

[0122]

[0123] The present invention not only reduces the noble metal loading but also improves its activity and stability in acidic OER by samarium-doped ruthenium oxide, which is of great significance for the practical application of PEMWE.

[0124] The present invention can significantly reduce the overpotential by doping ruthenium oxide with samarium. The overpotential of the best samarium-doped ruthenium oxide (Sm-20) is reduced by 61mV compared with ruthenium oxide, while the overpotential reduction of ruthenium oxide after modification by the doping strategy is limited.

[0125] Comparative Example 1

[0126] In the prior art, ruthenium oxide is obtained by doping with different elements. The overpotential analysis before and after doping is shown in Table 2.

[0127] Table 2 Comparison of OER catalytic performance of RuO2 doped with different elements

[0128]

[0129] It can be seen from Table 2 that ruthenium oxide modified by doping strategy can effectively reduce the overpotential.

[0130] Comparative Example 2

[0131] The addition amount of urea was changed, and the contents of other components and the preparation method were the same as those in Example 2.

[0132] When 0.6 g of urea was added, the resulting gel was incompletely gelled and solid, and there were not enough bubbles in the gel. Since a porous gel structure could not be formed, subsequent steps could not be performed.

[0133] The amount of urea added was 1.4 g, and a gel solid was obtained, wherein the pores in the gel structure were very large and the pores were unevenly dispersed, resulting in defects and unevenness on the catalyst.

[0134] Comparative Example 3

[0135] The temperature and holding time in step D were changed, and the remaining steps were the same as in Example 3. The contents of other components were also the same as in Example 3.

[0136] The mixture was placed in an oven at 110°C for 2 h to obtain an incompletely gelled gel solid.

[0137] After 8 hours of oven reaction at 170°C, the resulting gel had collapsed and was over-aged, affecting the activity and stability of the catalyst. Subsequent performance testing was impossible.

[0138] In summary, the present application prepared samarium-doped ruthenium oxide by the sol-gel method. The rare earth element samarium improved the electronic structure of the material, stabilized the active sites, and synergistically improved the electrocatalytic activity and stability of the material.

[0139] The present invention is not limited to the structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing ruthenium oxide doped with rare earth element samarium, characterized in that: include: Dissolving glucose and urea in water based on a predetermined ratio to obtain a first solution; Adding RuCl3 and SmCl3 to the first solution and mixing them uniformly to obtain a second solution; heating the second solution to obtain a gel solid precursor, and grinding the gel solid precursor into fine powder; The gel solid precursor powder is placed in air and heated to a predetermined temperature, and then cooled to room temperature to obtain samarium-doped ruthenium oxide.

2. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The glucose is dissolved in water at a ratio of 0.88-1.12 g / ml, and the urea is dissolved in water at a ratio of 0.14-0.26 g / ml.

3. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The mass ratio of glucose to urea is (4-6g):(0.8-1.2g).

4. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The amount of SmCl3 added is less than or equal to 28 mol% of RuCl3.

5. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The mass ratio of the total mass of RuCl3 and SmCl3 added to the mass of glucose in the first solution is (38-52 mg): (4.4-5.6 g).

6. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The mass ratio of the total mass of RuCl3 and SmCl3 added to the mass of glucose in the first solution is (35-55 mg): (4-6 g).

7. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The mixing time after adding RuCl3 and SmCl3 to the first solution was 55-65 minutes.

8. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The second solution is heated at a temperature of 134-146° C. for 4-6 hours.

9. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The second solution is heated at a temperature of 134-146° C. for a heating time of 4.5-5.5 h.

10. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: The second solution is heated at a temperature of 135-145° C. for a heating time of 4.6-5.4 h.

11. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: Grinding of the solid precursor of the gel was performed in an agate mortar.

12. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: When the gel solid precursor powder is heated in air, the heating rate is 2-4°C / min, the predetermined temperature is 470-530°C, and the holding time is 7.5-8.5h.

13. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: When the gel solid precursor powder is heated in air, the heating rate is 2-4°C / min, the predetermined temperature is 480-520°C, and the holding time is 7.5-8.5h.

14. The method for preparing rare earth element samarium-doped ruthenium oxide according to claim 1, characterized in that: When the gel solid precursor powder is heated in air, the heating rate is 2-4°C / min, the predetermined temperature is 485-515°C, and the holding time is 7.5-8.5h.

15. A rare earth element samarium-doped ruthenium oxide, prepared by the method for preparing rare earth element samarium-doped ruthenium oxide according to any one of claims 1 to 14, characterized in that: The molar percentage of the rare earth element samarium relative to the ruthenium element is less than or equal to 28 mol%.

16. Use of the rare earth element samarium-doped ruthenium oxide prepared by the method for preparing rare earth element samarium-doped ruthenium oxide according to any one of claims 1 to 14 or the rare earth element samarium-doped ruthenium oxide according to claim 15 in an acidic electrocatalytic oxygen evolution reaction.

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