Inzr solid solution loaded ptco bimetallic catalyst, and preparation method and application thereof

Abstract

This invention provides an InZr solid solution supported PtCo bimetallic catalyst, its preparation method, and its application, belonging to the field of catalyst preparation and hydrogen production energy applications. The invention employs a high-temperature melting method to prepare an InZr solid solution support, and then sequentially loads platinum and cobalt onto the support surface via a stepwise liquid-phase reduction method to obtain the InZr solid solution supported PtCo bimetallic catalyst. In this catalyst, the molar ratio of In to Zr is 1:0.05~1, the mass ratio of platinum atoms to InZr solid solution is 1:60~250, and the mass ratio of cobalt atoms to InZr solid solution is 1:10~200. The InZr solid solution surface has a high concentration of oxygen vacancies, which can promote the activation of water molecules; there is a synergistic effect between the platinum and cobalt bimetals and between the metals and the support. When catalyzing the hydrolysis of ammonia borane to produce hydrogen at room temperature and pressure, this catalyst can completely release hydrogen within 7.1 minutes, significantly outperforming single In2O3 supports or single-metal platinum catalysts. The preparation method of this invention is simple and the conditions are mild, showing good application prospects.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation and hydrogen energy application, specifically relating to an InZr solid solution supported PtCo bimetallic catalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen energy is considered one of the most promising clean energy sources due to its high calorific value, the fact that its only byproduct is water, and the absence of pollution. However, the large-scale application of hydrogen energy is still constrained by efficient, safe, and economical storage and transportation technologies. Physical hydrogen storage (high-pressure gaseous state, low-temperature liquid state) suffers from drawbacks such as high energy consumption and demanding equipment requirements. Therefore, exploring novel chemical hydrogen storage systems to achieve in-situ, controlled release of hydrogen has become an important direction in the current field of hydrogen energy research.

[0003] Ammonia borane possesses a theoretical hydrogen storage capacity of up to 19.6 wt%, and is stable at room temperature, non-toxic, and easy to transport, making it highly promising for chemical hydrogen storage. Hydrogen production via the hydrolysis of ammonia borane is one of the more promising methods. Under mild conditions of ambient temperature and pressure, ammonia borane can rapidly and efficiently release hydrogen through hydrolysis in the presence of a catalyst. Noble metal catalysts exhibit excellent catalytic performance in the hydrolysis of ammonia borane, but their high price and scarcity are major obstacles to their large-scale application. Although non-noble metals can also be used to prepare inexpensive catalysts, their catalytic activity and stability are still significantly inferior to those of noble metals.

[0004] To overcome the aforementioned shortcomings, researchers have attempted to utilize the synergistic effect between noble and non-noble metals to prepare bimetallic or multimetallic catalysts combining noble and non-noble metals. This strategy not only reduces the amount of noble metal used but also improves the catalytic performance of the catalyst. For example, Guan et al. (Angew. Chem. Int. Ed., 2025, 64, e202506869) prepared a catalyst combining noble and non-noble metals by supporting Ru and Ni on a Ti3C2 MXene support. Its high activity stemmed from the accelerating effect of the RuNi clusters and Ti3C2 on the catalytic process, as well as the H2 molecule transport promoted by the special RuNi cluster-MXene interface. Meanwhile, for supported catalysts, the structure and composition of the support also have a significant impact on catalytic performance. Studies have shown that oxygen vacancies in the catalyst support are beneficial for the activation of water molecules in the rate-determining step. For example, Zhang et al. (International Journal of Hydrogen Energy, 2022, 47, 7793-7801) reported a Co3O4-supported Ru nanoparticle catalyst rich in oxygen vacancies, which improved the catalytic activity and durability of hydrogen production from ammonia borane through the combined effects of oxygen vacancy regulation and morphology regulation. This demonstrates that regulating the oxygen vacancies on the support contributes to improving the catalytic performance of the catalyst for hydrogen production.

[0005] In₂O₃ and ZrO₂ surfaces readily form oxygen vacancies, making them common catalyst supports in heterogeneous catalytic reactions. However, no studies have been reported on hydrogen production from the hydrolysis of ammonia borane using solid solutions prepared with In and Zr as supports for noble and non-noble metal catalysis. Summary of the Invention

[0006] This invention provides an InZr solid solution-supported PtCo bimetallic catalyst, its preparation method, and its applications, addressing the problems of high noble metal content, low activity of non-noble metal catalysts, and insufficient oxygen vacancy regulation in existing ammonia borane hydrolysis hydrogen production catalysts. This catalyst can efficiently catalyze the hydrolysis of ammonia borane to produce hydrogen at ambient temperature and pressure, exhibiting excellent catalytic activity and promising application prospects.

[0007] To achieve the above objectives, the specific solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing an InZr solid solution supported PtCo bimetallic catalyst, comprising the following steps: Step 1: Grind and mix indium nitrate and zirconium nitrate evenly, then transfer to a crucible. Heat the crucible to 450-750℃ in a muffle furnace and hold for 2-4 hours. After natural cooling, grind to obtain InZr solid solution. Step 2: Disperse the InZr solid solution obtained in Step 1 uniformly in deionized water, add an aqueous solution of platinum source and stir to adsorb platinum ions onto the surface of the InZr solid solution, and then add sodium borohydride solution dropwise to reduce platinum to platinum nanoparticles. Step 3: Add a cobalt source to the system obtained in Step 2 and stir to allow cobalt ions to attach to the surface of the InZr solid solution. Then add sodium borohydride solution to reduce cobalt to cobalt nanoparticles. Step 4: Centrifuge to collect the precipitate in the solution obtained in Step 3, wash and vacuum dry to obtain the catalyst.

[0008] Furthermore, in step one, the molar ratio of indium nitrate to zirconium nitrate is 1:0.05~1.

[0009] Furthermore, in step one, the temperature is increased to 450-750°C in a muffle furnace at a heating rate of 1-5°C / min.

[0010] Further, in step two, the platinum source is any one of platinum hexahydroxide, chloroplatinic acid, dinitrosodiammineplatinum, or platinum nitrate; the amount of platinum source added is such that the mass ratio of Pt atoms to InZr solid solution is 1:60~250.

[0011] Furthermore, in step three, the cobalt source is any one of cobalt chloride, cobalt nitrate, or cobalt acetate; the amount of cobalt source added is such that the mass ratio of Co atoms to InZr solid solution is 1:10~200.

[0012] Furthermore, in step four, the specific parameters for vacuum drying are: drying at 50-80 ℃ for 6-12 h.

[0013] Secondly, the present invention provides an InZr solid solution supported PtCo bimetallic catalyst, which is prepared by the preparation method described above. The catalyst includes an InZr solid solution support and Pt nanoparticles and Co nanoparticles dispersed on the surface of the InZr solid solution support, wherein the molar ratio of In to Zr in the InZr solid solution support is 1:0.05~1.

[0014] Furthermore, in the catalyst, the mass ratio of Pt atoms to InZr solid solution is 1:60~250; the mass ratio of Co atoms to InZr solid solution is 1:10~200.

[0015] Thirdly, the present invention provides an application of the above-mentioned InZr solid solution supported PtCo bimetallic catalyst in the catalytic hydrolysis of ammonia borane to produce hydrogen.

[0016] Furthermore, the catalytic hydrolysis of ammonia borane to produce hydrogen is carried out at ambient temperature and pressure.

[0017] The functions of each raw material in this invention are explained below.

[0018] Indium nitrate: provides the indium source, and forms an InZr solid solution by high-temperature calcination with zirconium nitrate. Indium is one of the main components of the solid solution, and oxygen vacancies are easily formed on the surface of its oxide In2O3.

[0019] Zirconium nitrate: Provides a zirconium source to form a solid solution with indium nitrate. The introduction of zirconium can adjust the lattice structure and oxygen vacancy concentration of the solid solution, thereby improving the thermal stability and surface properties of the support.

[0020] Platinum source (platinum hexahydroxide, chloroplatinic acid, dinitrosodiammonium platinum, or platinum nitrate): provides the precursor of the active component platinum, which is reduced to generate Pt nanoparticles. Pt is a highly active catalytic center for the hydrolysis of ammonia borane.

[0021] Cobalt source (cobalt chloride, cobalt nitrate, or cobalt acetate): provides a precursor for the cobalt catalytic agent, which is reduced to generate Co nanoparticles. Co and Pt have a synergistic effect, reducing the amount of precious metals used while improving catalytic activity.

[0022] Sodium borohydride: a reducing agent used to reduce platinum and cobalt ions to zero-valent metal nanoparticles.

[0023] Deionized water: a solvent and dispersion medium used to disperse carriers and dissolve precursors.

[0024] Ethanol: a washing solvent used to remove impurities adsorbed on the surface of catalysts.

[0025] Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses a high-temperature melting method to prepare an InZr solid solution as a support. The surface of the bicomponent solid solution formed by In and Zr has a high concentration of oxygen vacancies. In the hydrolysis reaction of ammonia borane, the activation of water molecules is the key step (i.e., the rate-determining step) that determines the overall reaction rate. Oxygen vacancies can promote the activation of water molecules, thereby significantly improving the catalytic reaction rate.

[0026] (2) In this invention, Pt and Co are introduced separately by a stepwise liquid-phase reduction method. The Pt nanoparticles and Co nanoparticles in the prepared catalyst are well dispersed on the surface of the InZr solid solution support. There are significant synergistic effects between the Pt and Co bimetals and between the metal and the support, which can effectively improve the catalytic activity of the catalyst.

[0027] (3) The catalyst of the present invention exhibits excellent performance in the catalytic hydrolysis of ammonia borane to produce hydrogen. Experiments show that, under room temperature conditions, when using the catalyst of the present invention to catalyze the hydrolysis of ammonia borane, ammonia borane can be completely released into hydrogen within 7.1 minutes, which is much faster than catalysts using In2O3 support alone or catalysts supporting Pt alone, and also faster than comparative catalysts that undergo one-step co-reduction or reduce Co first and then Pt.

[0028] (4) The preparation method of the present invention is simple, easy to operate, and has mild conditions, making it easy to scale up for production. By adjusting the In / Zr ratio and the loading of Pt and Co, the catalytic performance can be further optimized, showing good application prospects.

[0029] The reason why this invention achieves the above-mentioned beneficial effects is that: First, the InZr solid solution is a two-component composite oxide formed by melting In2O3 and ZrO2 at high temperature. Due to the difference in ionic radius and valence state between In and Zr, a large number of lattice defects and surface oxygen vacancies are generated during the solid solution formation process. These oxygen vacancies can adsorb and activate water molecules, and the rate-determining step of the hydrolysis of ammonia borane is the activation of water molecules. Therefore, a high concentration of oxygen vacancies can significantly accelerate the reaction rate. Second, the preparation method of this invention adopts a stepwise liquid-phase reduction method, and the reduction order has an important influence on the catalyst performance. Experiments show that the catalytic effect of reducing Pt first and then Co (Example 1) is better than that of reducing Co first and then Pt (Comparative Example 4), and also better than that of one-step co-reduction (Comparative Example 3). This is mainly because reducing Pt first allows Pt to preferentially nucleate and grow on the support surface, forming fine and uniformly distributed Pt nanoparticles; the subsequently reduced Co is loaded on the support surface and works synergistically with Pt to exert a catalytic effect. However, when Co is reduced first, Co nucleates and grows on the support surface, potentially forming large particles or exhibiting uneven distribution, which affects the subsequent loading and dispersion of Pt, thereby reducing catalytic activity. Furthermore, the abundant oxygen vacancies on the InZr solid solution support surface can act as anchoring sites, strongly interacting with Pt and Co nanoparticles, improving the dispersion and stability of the metal nanoparticles, and preventing their agglomeration and deactivation during the reaction. Therefore, the catalyst of this invention utilizes the high oxygen vacancy concentration of the InZr solid solution support and the synergistic effect between the Pt and Co bimetals to rapidly and completely catalyze the hydrolysis of ammonia borane to produce hydrogen at ambient temperature and pressure. Attached Figure Description

[0030] Figure 1 This is a SEM image of the catalyst obtained in Example 1 of the present invention.

[0031] Figure 2 These are test graphs showing the catalytic hydrogen release performance of the catalysts obtained in Examples 1, 2, and Comparative Example 1 of this invention under room temperature conditions.

[0032] Figure 3 The graph shows the performance of the catalysts obtained in Example 1 and Comparative Example 2 of this invention in catalyzing the hydrogen release from ammonia borane hydrolysis at room temperature.

[0033] Figure 4 These are test graphs showing the catalytic hydrogen release performance of the catalysts obtained in Examples 1, 3, and 4 of this invention under room temperature conditions for hydrolysis of ammonia borane. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0035] This invention provides an InZr solid solution-supported PtCo bimetallic catalyst, its preparation method, and its application. This catalyst uses an InZr solid solution as a support, loading Pt and Co bimetallic components. Utilizing the high concentration of oxygen vacancies on the surface of the InZr solid solution and the synergistic effect between Pt and Co, it can efficiently catalyze the hydrolysis of ammonia borane to produce hydrogen under ambient temperature and pressure. The preparation method is described in detail below: Step 1: Preparation of InZr solid solution: Indium nitrate and zirconium nitrate are placed in a mortar at a molar ratio of 1:0.05~1 and ground for about 5 minutes to mix them evenly. The purpose of grinding is to ensure sufficient contact between the two salts and to refine the particles, which is beneficial for atomic diffusion during the subsequent high-temperature solid-phase reaction. The ground mixture is transferred to a crucible and placed in a muffle furnace. The temperature is increased to 450~750℃ at a heating rate of 1~5℃ / min and held at this temperature for 2~4 hours. Slow heating can prevent the sample from splashing due to excessive heating and is also conducive to the uniform formation of solid solution. Holding at this temperature allows the oxides of In and Zr to fully dissolve, forming a homogeneous solid solution. After natural cooling (natural cooling can avoid cracks and structural defects caused by rapid cooling), the sample is removed and ground again to obtain InZr solid solution powder. Step 2: Platinum Loading and Reduction: The InZr solid solution obtained in Step 1 is added to deionized water and sonicated for 5-10 minutes to ensure complete dispersion. The mixture is then stirred at room temperature for 0.5-2 hours to ensure uniform suspension of the support in the solution. Ultrasonic dispersion utilizes cavitation to break up support agglomerates, while stirring prevents particle settling. Then, an aqueous solution of a platinum source (selected from platinum hexahydroxide, chloroplatinic acid, dinitrosodiamineplatinum, or platinum nitrate) is added, and stirring continues at room temperature for 1-3 hours. During this process, platinum ions in the solution adsorb onto the surface of the InZr solid solution, providing a uniform distribution for subsequent reduction. Finally, sodium borohydride solution (usually 0.2 mol / L) is added dropwise, and stirring continues for 1-3 hours. Sodium borohydride, as a strong reducing agent, reduces the platinum ions adsorbed on the support surface to zero-valent platinum nanoparticles. Dropwise addition controls the reduction rate and avoids excessively high local concentrations that could lead to particle agglomeration. Step 3: Cobalt Loading and Reduction: Add a cobalt source (selected from cobalt chloride, cobalt nitrate, or cobalt acetate) to the system obtained in Step 2, and continue stirring at room temperature for 1-3 hours. During this process, cobalt ions adsorb onto the surface of the InZr solid solution loaded with platinum nanoparticles and form a bimetallic interface with platinum. Then, add sodium borohydride solution dropwise, and continue stirring for 1-3 hours to reduce the cobalt ions to zero-valent cobalt nanoparticles. Step 4, Post-processing: Centrifuge the solution obtained in Step 3 and collect the precipitate. Wash the precipitate 2-3 times with deionized water and ethanol, respectively, to remove unreacted ions and impurities. Finally, place the collected material in a vacuum drying oven and dry at 50-80℃ for 6-12 hours to obtain the final InZr solid solution-supported PtCo bimetallic catalyst. Vacuum drying can prevent the metal nanoparticles from oxidizing during heating.

[0036] The catalyst prepared through the above steps has the following microstructure: an InZr solid solution serves as the support, with fine platinum and cobalt nanoparticles uniformly dispersed on its surface. The particle size is in the nanometer range, and the dispersion is excellent. In the catalyst, the molar ratio of indium to zirconium is 1:0.05~1, the mass ratio of platinum atoms to InZr solid solution is 1:60~250, and the mass ratio of cobalt atoms to InZr solid solution is 1:10~200.

[0037] Example 1

[0038] This embodiment provides a method for preparing a catalyst, including the following steps: Step 1: Place 602 mg of indium nitrate and 429 mg of zirconium nitrate (molar ratio In:Zr=2:1) ​​into a mortar and grind for 5 minutes. Stir and mix evenly, transfer to a crucible, heat to 500°C in a muffle furnace at a heating rate of 2°C / min and hold for 2 hours. After natural cooling, grind to obtain InZr solid solution. Step 2: Add 100 mg of the above InZr solid solution to 100 mL of deionized water, sonicate for 10 minutes until completely dispersed, and stir at room temperature for 1 hour. Add 4 mL of 0.0001 g / mL chloroplatinic acid aqueous solution to the above solution, and continue stirring at room temperature for 1 hour to allow platinum ions to be adsorbed onto the surface of the solid solution; add 10 mL of 0.2 mol / L sodium borohydride solution dropwise, and continue stirring for 1 hour to reduce platinum ions to platinum nanoparticles. Step 3: Add 29.1 mg of cobalt nitrate hexahydrate to the above solution and continue stirring at room temperature for 1 hour to allow cobalt ions to be adsorbed onto the surface of the solid solution. Then, add 10 mL of 0.2 mol / L sodium borohydride solution dropwise and continue stirring for 1 hour to reduce the cobalt ions to cobalt nanoparticles. Step 4: Centrifuge to collect the precipitate, wash it three times each with water and ethanol, and dry the collected material in a vacuum drying oven at 60°C for 12 hours to obtain the catalyst.

[0039] Figure 1 The image shows a SEM image of the catalyst obtained in Example 1. As can be seen from the image, the InZr solid solution consists of prismatic particles piled together, with fine platinum and cobalt nanoparticles uniformly dispersed on the surface. These nanoparticles are small in size, uniformly distributed, and show no obvious agglomeration, indicating that the method of this invention can achieve good dispersion of the metal components on the support surface.

[0040] Example 2

[0041] The only difference between this embodiment and Example 1 is that in step one, 301 mg of indium nitrate and 429 mg of zirconium nitrate (molar ratio In:Zr=1:1) are placed in a mortar and ground for 5 minutes, then stirred and mixed evenly. The mixture is then transferred to a crucible and heated to 500°C in a muffle furnace at a heating rate of 2°C / min and held for 2 hours. After natural cooling, the mixture is ground to obtain an InZr solid solution.

[0042] Comparative Example 1 (Single In2O3 support) The only difference between this comparative example and Example 1 is that in step one, 602 mg of indium nitrate (without zirconium nitrate) was placed in a mortar and ground for 5 minutes, then stirred and mixed evenly. The mixture was then transferred to a crucible and heated to 500°C in a muffle furnace at a heating rate of 2°C / min and held for 2 hours. After natural cooling, the mixture was ground to obtain the In2O3 support.

[0043] Comparative Example 2 (Platinum only, no cobalt) The only difference between this comparative example and Example 1 is that it does not include step three.

[0044] Comparative Example 3 (One-step co-reduction of platinum and cobalt) The only difference between this comparative example and Example 1 is that steps two and three are combined into the following single step: 100 mg of the solid solution is dispersed in 100 mL of deionized water, sonicated for 10 minutes, and then stirred for 1 hour. Simultaneously, 4 mL of chloroplatinic acid aqueous solution (0.0001 g / mL) and 29.1 mg of cobalt nitrate hexahydrate are added, and stirring continues for 1 hour. Then, 20 mL of a 0.2 mol / L sodium borohydride solution is added all at once, and stirring continues for 1 hour.

[0045] Comparative Example 4 (Cobalt reduction followed by platinum reduction) The only difference between this comparative example and Example 1 is that the order of steps two and three is reversed, with cobalt loading in step three performed first, followed by platinum loading in step two.

[0046] Catalyst performance testing methods The hydrogen production performance of the catalysts prepared in the above examples and comparative examples was evaluated by water displacement under constant temperature magnetic stirring at 25℃. Specific procedure: 10 mg of catalyst dispersed in 5 mL of deionized water was added to a round-bottom flask, followed by the rapid addition of 10 mL of deionized water containing 1 mmol of ammonia borane. The reaction system was immediately sealed, and the volume of hydrogen produced was recorded over time. Each sample was tested three times, and the average value was taken.

[0047] Performance test results and analysis (1) Comparison of different In / Zr ratios with single In2O3 support Figure 2 Performance curves of the catalysts obtained in Examples 1, 2, and Comparative Example 1 for catalyzing the hydrogen release of ammonia borane hydrolysis at room temperature are presented. The results show that the catalyst obtained in Example 1 completely releases hydrogen from ammonia borane within 7.1 minutes; the catalyst obtained in Example 2 completely releases hydrogen within 9.7 minutes; while the catalyst obtained in Comparative Example 1 requires 16.7 minutes to completely release hydrogen. This indicates that using an InZr solid solution as a support (Examples 1 and 2) significantly improves catalytic activity compared to using a single In2O3 support (Comparative Example 1). This is because the higher oxygen vacancy concentration on the surface of the InZr solid solution is beneficial for the activation of water molecules, thereby accelerating the hydrolysis reaction of ammonia borane. Furthermore, an In to Zr molar ratio of 2:1 (Example 1) is superior to 1:1 (Example 2), indicating that an appropriate ratio of Zr doping can optimize the oxygen vacancy concentration and surface properties of the solid solution.

[0048] (2) Comparison between bimetallic and monometallic platinum Figure 3 Catalytic performance curves for the catalysts obtained in Example 1 and Comparative Example 2 are presented. The results show that the bimetallic catalyst obtained in Example 1 completely releases hydrogen within 7.1 minutes, while the monometallic platinum catalyst obtained in Comparative Example 2 requires 28.7 minutes for complete hydrogen release. The catalytic rate of Example 1 is much faster than that of Comparative Example 2, indicating that the introduction of cobalt has a significant synergistic effect. Although platinum alone is active, the electronic and geometric effects between platinum and cobalt bimetals can further improve the catalytic efficiency. Simultaneously, the addition of cobalt reduces the amount of precious metal platinum required.

[0049] (3) Comparison of different restoration orders Figure 4Catalytic performance curves of the catalysts obtained in Example 1, Comparative Example 3, and Comparative Example 4 are presented. The results show that the catalyst obtained in Example 1 (reducing platinum first, then cobalt) completely released hydrogen within 7.1 minutes; the catalyst obtained in Comparative Example 3 (one-step co-reduction) required 11.5 minutes; and the catalyst obtained in Comparative Example 4 (reducing cobalt first, then platinum) required 13.2 minutes. This indicates that the stepwise reduction sequence, with platinum reduction preceding cobalt reduction, is optimal. Reducing platinum first allows it to preferentially nucleate on the support surface, forming fine and uniformly distributed platinum nanoparticles; subsequently, the reduced cobalt is loaded onto the support surface, working synergistically with platinum to exert its catalytic effect. In contrast, in one-step co-reduction, platinum and cobalt may nucleate separately, acting independently with a weaker synergistic effect; when cobalt is reduced first, cobalt ions are more difficult to reduce than platinum ions, potentially forming larger cobalt particles that occupy active sites on the support surface, hindering subsequent platinum loading and dispersion, thus resulting in lower catalytic activity.

[0050] In summary, the InZr solid solution-supported PtCo bimetallic catalyst prepared by this invention possesses a solid solution support with high oxygen vacancy concentration and uniformly dispersed platinum and cobalt nanoparticles. Through bimetallic synergy and metal-support synergy, it exhibits excellent catalytic activity for hydrogen production from ammonia borane hydrolysis under ambient temperature and pressure. The preparation method is simple and the conditions are mild, showing promising application prospects.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various corresponding changes and modifications to the present invention without departing from its spirit and scope, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A method for preparing an InZr solid solution supported PtCo bimetallic catalyst, characterized in that, Includes the following steps: Step 1: Grind and mix indium nitrate and zirconium nitrate evenly, then transfer to a crucible. Heat the crucible to 450-750℃ in a muffle furnace and hold for 2-4 hours. After natural cooling, grind to obtain InZr solid solution. Step 2: Disperse the InZr solid solution obtained in Step 1 uniformly in deionized water, add an aqueous solution of platinum source and stir to adsorb platinum ions onto the surface of the InZr solid solution, and then add sodium borohydride solution dropwise to reduce platinum to platinum nanoparticles. Step 3: Add a cobalt source to the system obtained in Step 2 and stir to allow cobalt ions to attach to the surface of the InZr solid solution. Then add sodium borohydride solution to reduce cobalt to cobalt nanoparticles. Step 4: Centrifuge to collect the precipitate in the solution obtained in Step 3, wash and vacuum dry to obtain the catalyst.

2. The preparation method according to claim 1, characterized in that, In step one, the molar ratio of indium nitrate to zirconium nitrate is 1:0.05~1.

3. The preparation method according to claim 1, characterized in that, In step one, the temperature is increased to 450-750°C in a muffle furnace at a heating rate of 1-5°C / min.

4. The preparation method according to claim 1, characterized in that, In step two, the platinum source is any one of platinum hexahydroxide, chloroplatinic acid, dinitrosodiammineplatinum, or platinum nitrate; the amount of platinum source added is such that the mass ratio of Pt atoms to InZr solid solution is 1:60~250.

5. The preparation method according to claim 1, characterized in that, In step three, the cobalt source is any one of cobalt chloride, cobalt nitrate, or cobalt acetate; the amount of cobalt source added is such that the mass ratio of Co atoms to InZr solid solution is 1:10~200.

6. The preparation method according to claim 1, characterized in that, In step four, the specific parameters for vacuum drying are: drying at 50-80 ℃ for 6-12 h.

7. A PtCo bimetallic catalyst supported on an InZr solid solution, characterized in that, The catalyst is prepared by any one of claims 1-6, and comprises an InZr solid solution support and Pt nanoparticles and Co nanoparticles dispersed on the surface of the InZr solid solution support, wherein the molar ratio of In to Zr in the InZr solid solution support is 1:0.05~1.

8. The catalyst according to claim 7, characterized in that, In the catalyst, the mass ratio of Pt atoms to InZr solid solution is 1:60~250; the mass ratio of Co atoms to InZr solid solution is 1:10~200.

9. The application of the InZr solid solution supported PtCo bimetallic catalyst according to any one of claims 7-8 in the catalytic hydrolysis of ammonia borane to produce hydrogen.

10. The application according to claim 9, characterized in that, The catalytic hydrolysis of ammonia borane to produce hydrogen is carried out at ambient temperature and pressure.

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