Preparation method of catalyst for ammonia borane hydrolysis hydrogen evolution based on efficient multifunctional active sites

Abstract

The invention discloses a preparation method of a catalyst for ammonia borane hydrogen desorption by water based on efficient multifunctional active sites, which comprises the following steps: firstly, adding prepared MXene into deionized water to form a dispersion solution, then dissolving Co (NO3) 2.6 H2O and Ni (NO3) 2.6 H2O solutions into a polyvinylpyrrolidone solution, then adding the solution into the MXene solution to form a metal mixed dispersion solution, and finally adding the metal mixed dispersion solution into the MXene solution to form the catalyst for ammonia borane hydrogen desorption by water. The preparation method comprises the following steps: adding a NaBH4 solution into a tubular furnace to form CoB-Ni3B / MXene, calcining the CoB-Ni3B / MXene in the tubular furnace, and obtaining the CoB-NiCoP-Ni3B / MXene catalyst through a phosphorus induction method. According to the method, the preparation process is controllable, the defects that a noble metal-based catalyst is high in price and limited in resource in hydrogen production by hydrolysis of ammonia borane are overcome, and the problems that non-noble metal is easy to aggregate in the preparation process and the non-noble metal catalyst is low in activity and poor in stability in hydrogen production by hydrolysis of ammonia borane are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials and relates to a method for preparing an ammonia borane water decomposition hydrogen catalyst based on high-efficiency multifunctional active sites. Background Art

[0002] A hydrogen energy system, with hydrogen storage and conversion as its primary link, has promising application prospects. As a highly energy-dense and environmentally friendly energy storage material, hydrogen is considered a very promising new energy source, and its practical application is of great significance.

[0003] Boron hydrides (NH3BH3, NaBH4) play a vital role in the development of hydrogen energy as safe and efficient solid-state hydrogen storage materials. NH3BH3, with its high hydrogen content (19.6 wt%), low molecular weight (30.87 g / mol), good stability, and non-toxicity, holds great potential for development in hydrogen production. Currently, noble metal-based catalysts exhibit excellent catalytic activity in hydrogen evolution reactions using ammonia borane. However, their low crustal abundance, high cost, and poor stability hinder their widespread application.

[0004] Therefore, the development of low-cost, highly active catalysts is of great significance for sustainable energy development. It is one of the key scientific issues in hydrogen evolution from water by ammonia borane and a current research hotspot and focus in this field. Transition metals Co and Ni, as low-cost transition metals, have been extensively studied in heterogeneous catalysis. Through rational structural design and compositional manipulation, the active structural composition of the non-precious metal Co can be optimized, improving the catalytic activity of the catalyst. However, the low-valent element B produced during the hydrolysis hydrogen evolution reaction has a strong reducing property, resulting in reduced catalytic activity. TMPs (transition metal phosphides) have great potential for development in heterogeneous catalysis due to their abundant active sites and tunable compositional structure. During the synthesis of phosphides, lattice stress caused by phosphorus atom substitution can lead to metal phosphide aggregation, thereby affecting catalytic activity. Highly active catalysts can be obtained by constructing multifunctional active site structures on the support surface. Establishing the interaction between the TMP active phase and the non-metallic active sites is crucial for the rational construction of efficient bifunctional active sites. Therefore, an effective strategy is to use MXene as a support to anchor nanoparticulate TMPs, creating a TMP-support hybrid structure. However, the construction of dual active sites based on highly active metals and supports on the catalyst surface still needs further improvement and research. Summary of the Invention

[0005] In response to the above technical problems, the present invention aims to provide a method for preparing a catalyst for ammonia borane hydrolysis to produce hydrogen based on high-efficiency multifunctional active sites. First, the prepared MXene is added to deionized water to form a dispersed solution, and then Co(NO3)2·6H2O and Ni(NO3)2·6H2O solutions are dissolved in polyvinyl pyrrolidone solution, which is then added to the MXene solution to form a metal mixed dispersed solution. NaBH4 solution is slowly added to form CoB-Ni3B / MXene, and finally the CoB-Ni3B / MXene is placed in a tubular furnace and calcined to obtain a CoB-NiCoP-Ni3B / MXene catalyst by a phosphorus induction method. The preparation process of this method is controllable, which overcomes the defects of expensive and resource-limited precious metal-based catalysts in ammonia borane hydrolysis to produce hydrogen, and solves the problems that non-precious metals are easy to aggregate during the preparation process and that non-precious metal catalysts have low activity and poor stability in ammonia borane hydrolysis to produce hydrogen.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing an ammonia borane water decomposition hydrogen catalyst based on a high-efficiency multifunctional active site is carried out in the following steps in sequence:

[0008] (1) Preparation of MXene

[0009] 1.5 g of Ti3AlC2 was placed in the lining of the reactor, and then 30 mL of HF solution was slowly added to the Ti3AlC2 powder at a speed of 400 rpm. The mixture was stirred at 60 ° C for 24 h. After cooling to room temperature, the reaction solution was taken out and dispersed in 60-100 mL of deionized water. The mixture was washed repeatedly until the pH value reached 6. The precipitate was then dried in a vacuum oven at 50 ° C for 8-12 h to obtain Ti3C2 powder, i.e., MXene.

[0010] (2) Dissolution and dispersion

[0011] 100 mg of MXene was added to 50 mL of deionized water, and stirring and ultrasonication were performed alternately for 2 h to obtain a uniformly dispersed MXene suspension solution;

[0012] (3) Prepare metal ion solution

[0013] 600 mg of polyvinyl pyrrolidone was added to 5 mL of deionized water, and then Co(NO3)2·6H2O and Ni(NO3)2·6H2O were dissolved in 5 mL of distilled water to form aqueous solutions, which were then added to the polyvinyl pyrrolidone solution and stirred for 30 min to form a uniform metal ion solution;

[0014] (4) Preparation of phosphating precursor materials

[0015] The uniform metal ion solution obtained in step (3) was added to the MXene suspension obtained in step (2), and the mixture was stirred for 30 min. NaBH4 solution was added and the mixture was stirred and reacted for 1 h. The mixture was then centrifuged at 6000 rpm for 5 min. 7 mL of water and 7 mL of ethanol were then added, respectively. The mixture was centrifuged at 6000 rpm for 5 min again, and then dried at 40 ° C for 12 h to obtain a CoB-Ni3B / MXene precursor material.

[0016] (5) Preparation of phosphorus catalyst

[0017] The CoB-Ni3B / MXene precursor material was placed in a tube furnace and phosphating and calcining was carried out by a phosphorus-induced process under an argon atmosphere to obtain the CoB-NiCoP-Ni3B / MXene catalyst.

[0018] As a limitation of the present invention, in step (3), the molar ratio of Co(NO3)2·6H2O to Ni(NO3)2·6H2O is 1:1.

[0019] As another limitation of the present invention, in step (4), the NaBH4 solution is obtained by dissolving 1900 mg of sodium borohydride in 10 mL of deionized water containing 40 mg of sodium hydroxide and stirring evenly; the dropping rate of the NaBH4 is 0.6 to 0.8 mL / min.

[0020] In the present invention, slowly adding NaBH4 helps to accurately control the reaction rate, avoid excessively violent reactions, make the reaction process smoother, and evenly carry out reduction reactions and other reactions, which is beneficial to the uniform distribution of active components, thereby improving the performance and quality of the catalyst; if the droplet acceleration rate is less than 0.6 mL / min, the local concentration of NaBH4 in the reaction system will be at a low level for a long time, and the nucleation process will be slow, resulting in a small number of generated crystal nuclei and the formation of larger and widely distributed particles; if the droplet acceleration rate is greater than 0.8 mL / min, the NaBH4 concentration in the system will be instantly increased, triggering violent reduction of the metal precursor, generating a large number of crystal nuclei in a short time, forming irregular agglomerates or chain structures, thereby causing small particle aggregation, reducing the specific surface area and active site exposure.

[0021] As a third limitation of the present invention, in step (5), in the phosphorus induction process, the phosphorus source is NaH2PO2; and the mass ratio of the CoB-Ni3B / MXene precursor material to NaH2PO2 is 1:10.

[0022] As a fourth limitation of the present invention, in step (5), the heating rate during calcination is 3-10°C / min, the temperature is 250-450°C, and the time is 60-120 min.

[0023] In the present invention, the speed of the calcination heating process directly affects the generation rate of phosphorus-containing gas, the formation of phosphide and the in-situ doping process. Specifically, when the heating rate is 3 to 10°C / min, PH3 will be continuously and stably released to promote the layer-by-layer phosphating of the metal surface, so that the formed phosphide grain size is uniform and the crystallinity is high; if the heating rate is less than 3°C / min, the residence time of sodium hypophosphite in the low temperature zone will be prolonged, thereby causing it to partially decompose into pyrophosphate instead of PH3, significantly reducing the utilization rate of the effective phosphorus source; if the heating rate is greater than 10°C / min, sodium hypophosphite will be concentratedly decomposed in a short period of time, and the PH3 generation rate will be much higher than the consumption capacity of the metal precursor, resulting in excessively high local PH3 concentration, causing metal agglomeration and decreased catalytic activity.

[0024] Furthermore, during the phosphorus induction process, phosphorus-containing gas and phosphide formation reactions occur. The calcination time and temperature during this process have a significant impact on the phosphorus induction process and the formation and growth of phosphide crystal nuclei. When the calcination temperature is between 250°C and 450°C, sodium hypophosphite gradually decomposes to produce active phosphorus-containing gas, PH3, which gradually phosphatizes the surface of the metal precursor, forming small-sized crystal nuclei that are conducive to the formation of a high specific surface area and the exposure of active sites. If the temperature is less than 250°C, the sodium hypophosphite decomposition reaction kinetics are hindered, and the amount of PH3 generated is extremely small, resulting in incomplete phosphating of the metal precursor and a large amount of unreacted metal oxide remaining in the product, which reduces catalytic activity. If the temperature is greater than 450°C, atomic mobility is increased, forming elemental metal and free phosphorus, leading to the fusion growth of phosphide particles and destroying catalytic activity. The purpose of holding the catalyst for 60 to 120 minutes is to ensure that PH3 is in full contact with the metal precursor and to complete the layer-by-layer phosphating from the surface to the bulk. If the holding time is less than 60 minutes, PH3 will not be fully diffused, and only the metal surface will be phosphated, resulting in uneven grain size. If the holding time is greater than 120 minutes, grain ripening will be aggravated, and small particles will dissolve and deposit on the surface of large particles, resulting in a decrease in specific surface area, a reduction in active sites, and a decrease in catalytic activity.

[0025] The present invention also has a limitation that the structure of the catalyst CoB-NiCoP-Ni3B / MXene is that CoB, NiCoP, and Ni3B are in situ grown on a MXene support.

[0026] The active center catalyst containing CoB, NiCoP and Ni3B prepared by the present invention exhibits excellent catalytic activity in the process of hydrogen production from ammonia borane. Among them, the introduction of phosphorus promotes partial phosphating at the interface of Ni3B and CoB, generating NiCoP active centers, forming a CoB-NiCoP-Ni3B multi-active center model. Density functional theory calculations show that NiCoP activates and dissociates H2O molecules, promoting the dissociation of H2O molecules into H· and OH· free radicals, and CoB activates ammonia borane, promoting the dissociation of NH3BH3 molecules into NH3BH2OH· and H· free radicals. The two H· free radicals generated then combine to form H2 molecules. In addition, Ni3B, CoB and MXene jointly promote the desorption of H2 molecules, that is, CoB and Ni3B form a heterostructure interface, promoting the transfer of electrons from CoB to Ni3B. This charge redistribution further optimizes the H2 adsorption energy and accelerates desorption. The excellent conductivity of MXene facilitates electron transfer to the Ni3B / CoB active sites, maintaining surface charge balance and reducing the kinetic resistance to H2 desorption. The constructed three-component multi-active-site catalyst reduces the dissociation activation energy between ammonia borane and H2O molecules, promoting hydrogen desorption.

[0027] The above technical solution of the present invention is taken as a whole, and the various steps are closely related and influence each other, which jointly determine the morphological characteristics and performance of the product.

[0028] The above technical solution has the following advantages or beneficial effects:

[0029] 1. The CoB-NiCoP-Ni3B / MXene catalyst prepared by the present invention has good stability and high activity in hydrogen decomposition by ammonia borane water. The TOF value based on Ni or Co active elements reaches 70min. -1 ;

[0030] 2. The catalyst prepared by the present invention does not use precious metals, thus overcoming the defects of expensive and resource-limited precious metal-based catalysts in hydrogen production by hydrolysis of ammonia borane;

[0031] 3. The present invention performs a one-step NaBH4 reduction on the cobalt metal surface and introduces a phosphorus-induced method to form NiCoP, thereby establishing the interaction between the TMPs active phase and the non-metallic B and P active sites, constructing a high-efficiency multifunctional active site. The prepared catalyst solves the problems of easy aggregation of non-precious metal-based catalysts during the preparation process and low activity and poor stability of non-precious metal-based catalysts in hydrogen production by hydrolysis of ammonia borane.

[0032] The invention is suitable for preparing ammonia borane water decomposition hydrogen catalyst.

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 X-ray powder diffraction patterns of CoB-Ni3B / MXene and CoB-NiCoP-Ni3B / MXene prepared in Example 1 of the present invention;

[0035] Figure 2 The SEM image of MXene prepared in Example 1 of the present invention and the TEM and HRTEM images of CoB-NiCoP-Ni3B / MXene, wherein: a is the SEM image of MXene, b and c are the TEM images of CoB-NiCoP-Ni3B / MXene, and d is the HRTEM image of CoB-NiCoP-Ni3B / MXene;

[0036] Figure 3 The catalytic activity diagrams of the catalysts prepared in Example 1 and Comparative Examples 1 to 7 of the present invention are shown, wherein: a is a catalytic hydrogen production performance diagram of different catalysts, and b is a bar graph of the catalytic hydrogen production activity TOF of different catalysts. DETAILED DESCRIPTION

[0037] The following embodiments are merely some of the embodiments of the present invention, rather than all of them. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0038] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.

[0039] Example 1

[0040] This example prepares a CoB-NiCoP-Ni3B / MXene catalyst, and the preparation process and steps are as follows:

[0041] (1) Preparation of MXene

[0042] 1.5 g of Ti3AlC2 was placed in the lining of the reactor, and then 30 mL of HF solution was slowly added to the Ti3AlC2 powder at a speed of 400 rpm. The mixture was stirred at 60 ° C for 24 h. After cooling to room temperature, the reaction solution was taken out and dispersed in 60 mL of deionized water. The mixture was washed repeatedly until the pH value reached 6. The precipitate was then dried in a vacuum oven at 50 ° C for 8 h to obtain Ti3C2 powder, namely MXene.

[0043] (2) Dissolution and dispersion

[0044] 100 mg of MXene was added to 50 mL of deionized water, and stirring and ultrasonication were performed alternately for 2 h to obtain a uniformly dispersed MXene suspension solution;

[0045] (3) Prepare metal ion solution

[0046] 600 mg of polyvinyl pyrrolidone was added to 5 mL of deionized water, and then 1.4 mmol of Co(NO3)2·6H2O and 1.4 mmol of Ni(NO3)2·6H2O were dissolved in 5 mL of distilled water to form aqueous solutions, which were then added to the polyvinyl pyrrolidone solution and stirred for 30 min to form a uniform metal ion solution;

[0047] (4) Preparation of phosphating precursor materials

[0048] The uniform metal ion solution obtained in step (3) was added to the MXene suspension obtained in step (2), stirred for 30 min, and NaBH4 solution was added (NaBH4 solution preparation method: 1900 mg of sodium borohydride was dissolved in 10 mL of deionized water containing 40 mg of sodium hydroxide; the addition rate of NaBH4 solution was 0.7 mL / min) and the reaction was continued by stirring for 1 h. The mixed solution was then centrifuged at 6000 rpm for 5 min, and then centrifuged at 6000 rpm for 5 min with 7 mL of water and 7 mL of ethanol, respectively. The mixture was then dried in a vacuum drying oven at 40 ° C for 12 h to obtain CoB-Ni3B / MXene precursor material;

[0049] (5) Preparation of phosphorus catalyst

[0050] The CoB-Ni3B / MXene precursor material was placed in a tubular furnace and phosphating calcined by a phosphorus-induced process under an argon atmosphere. The phosphorus source was NaH2PO2, and the mass ratio of the precursor to NaH2PO2 was 1:10. The heating rate during calcination was 3°C / min, the temperature was 250°C, and the time was 120min to obtain the CoB-NiCoP-Ni3B / MXene catalyst.

[0051] The catalyst prepared in this example was subjected to a series of structural characterizations, and the specific results are as follows:

[0052] like Figure 1 , is the X-ray powder diffraction pattern of CoB-Ni3B / MXene and CoB-NiCoP-Ni3B / MXene prepared in step (4) and step (5) of this embodiment. Figure 1 The prepared catalysts correspond to standard charts for CoB (JCPDS No. 03-0959), Ni3B (JCPDS No. 82-1699), and NiCoP (JCPDS No. 71-2336). This indicates that the target catalyst, CoB-NiCoP-Ni3B / MXene, was successfully synthesized through a one-step NaBH4 reduction and phosphorus induction process.

[0053] like Figure 2 Figures 1 and 2 show the SEM image of the MXene prepared in this example, as well as the TEM and HRTEM images of CoB-NiCoP-Ni3B / MXene. Figure a shows the SEM image of the MXene, b and c show the TEM images of CoB-NiCoP-Ni3B / MXene, and d shows the HRTEM image of CoB-NiCoP-Ni3B / MXene. Figure a shows the morphology of the MXene, which is a stacked sheet. Figure d shows the HRTEM image of CoB-NiCoP-Ni3B / MXene, where lattice fringes of CoB, NiCoP, and Ni3B are detected, respectively. Furthermore, it can be seen that the CoB, NiCoP, and Ni3B structures were successfully synthesized, which is consistent with the XRD results.

[0054] Examples 2 to 4 Preparation of a CoB-NiCoP-Ni3B / MXene Catalyst

[0055] In this example, CoB-NiCoP-Ni3B / MXene catalysts were prepared. The specific preparation method was similar to that in Example 1, with the only difference being that the technical parameters during the preparation process were different, as shown in the table below:

[0056]

[0057] Comparative Example

[0058] In order to explore the effects of different parameters and different reactants in the preparation process of the present invention on the performance of the product of the present invention, the following comparative experiments were conducted. Different catalysts were prepared in the following comparative examples, as follows:

[0059] Comparative Example 1

[0060] In this comparative example, a catalyst for hydrogen decomposition by water using ammonia borane was prepared. The preparation process was similar to that in Example 1, except that in step (3), the molar ratio of Co(NO3)2·6H2O to Ni(NO3)2·6H2O was 3:1.

[0061] Comparative Example 2

[0062] In this comparative example, a catalyst for hydrogen decomposition by water using ammonia borane was prepared. The preparation process was similar to that in Example 1, except that in step (3), the molar ratio of Co(NO3)2·6H2O to Ni(NO3)2·6H2O was 1:3.

[0063] Comparative Example 3

[0064] In this comparative example, a CoB-Ni3B / MXene catalyst was prepared. The preparation process was similar to that of Example 1, except that step (5) was not performed, that is, the precursor was not subjected to phosphating treatment.

[0065] Comparative Example 4

[0066] In this comparative example, a Ni3B / MXene catalyst was prepared. The preparation process was similar to that of Example 1, except that Co(NO3)2·6H2O was not added in step (3), and the phosphating treatment in step (5) was not performed.

[0067] Comparative Example 5

[0068] In this comparative example, a CoB / MXene catalyst was prepared. The preparation process was similar to that of Example 1, except that Ni(NO3)2·6H2O was not added in step (3), and the phosphating treatment in step (5) was not performed.

[0069] Comparative Example 6

[0070] In this comparative example, a NiP / MXene catalyst was prepared. The preparation process was similar to that of Example 1, except that Co(NO3)2·6H2O was not added in step (3).

[0071] Comparative Example 7

[0072] In this comparative example, a CoP / MXene catalyst was prepared. The preparation process was similar to that of Example 1, except that Ni(NO3)2·6H2O was not added in step (3).

[0073] Performance Testing

[0074] 10 mg of the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were respectively mixed with 5 mL of aqueous solution by ultrasonication to form a uniform mixture. 0.045 g of ammonia borane was then added to the flask. Hydrolysis and hydrogen production were carried out in a water bath at 30° C. The time required to produce 5 mL of hydrogen was recorded. The specific results are as follows:

[0075] Figure 3 The experimental results of hydrogen evolution from ammonia borane catalyzed by different catalysts are shown in Table 1. Figure 3 As can be seen from Figure (a): Under the same test conditions, the time required for the catalytic reaction of CoB-NiCoP-Ni3B / MXene is the shortest compared to other materials. Figure 3 As can be seen from Figure (b), the TOF of CoB-NiCoP-Ni3B / MXene prepared in Example 1 is much higher than that of other catalysts, and it has excellent catalytic activity, with the highest activity being 70 min -1 The performance improvement is attributed to the construction of multifunctional active sites: CoB, NiCoP, and Ni3B. The present invention uses MXene as a carrier, and introduces P through a one-step NaBH4 reduction and phosphorus induction strategy to form CoB, NiCoP, and Ni3B that are in situ grown on the MXene carrier. This process avoids the agglomeration phenomenon that occurs during the growth of non-precious metal catalysts by introducing the MXene carrier and phosphorus. The catalyst constructed by the synergistic one-step reduction and phosphorus induction method of the present invention greatly improves the catalytic activity and stability of the catalyst in the hydrolysis of ammonia borane.

[0076] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a catalyst for hydrogen decomposition by water using ammonia borane based on high-efficiency multifunctional active sites, characterized in that: Follow the steps below in order: (1) Preparation of MXene 1.5 g of Ti3AlC2 was placed in the lining of the reactor, and then 30 mL of HF solution was slowly added to the Ti3AlC2 powder at a speed of 400 rpm. The mixture was stirred at 60 ° C for 24 h. After cooling to room temperature, the reaction solution was taken out and dispersed in 60-100 mL of deionized water. The mixture was washed repeatedly until the pH value reached 6. The precipitate was then dried in a vacuum oven at 50 ° C for 8-12 h to obtain Ti3C2 powder, i.e., MXene. (2) Dissolution and dispersion 100 mg of MXene was added to 50 mL of deionized water, and stirring and ultrasonication were performed alternately for 2 h to obtain a uniformly dispersed MXene suspension solution; (3) Prepare metal ion solution 600 mg of polyvinyl pyrrolidone was added to 5 mL of deionized water, and then Co(NO3)2·6H2O and Ni(NO3)2·6H2O were dissolved in 5 mL of distilled water respectively, and then added to the polyvinyl pyrrolidone solution and stirred for 30 min to form a uniform metal ion solution; (4) Preparation of phosphating precursor materials The uniform metal ion solution obtained in step (3) was added to the MXene suspension obtained in step (2), and the mixture was stirred for 30 min. NaBH4 solution was added and the mixture was stirred and reacted for 1 h. The mixture was then centrifuged at 6000 rpm for 5 min. 7 mL of water and 7 mL of ethanol were then added, respectively. The mixture was centrifuged at 6000 rpm for 5 min again, and then dried at 40 ° C for 12 h to obtain a CoB-Ni3B / MXene precursor material. (5) Preparation of phosphorus catalyst The CoB-Ni3B / MXene precursor material was placed in a tube furnace and phosphating and calcining was carried out by a phosphorus-induced process under an argon atmosphere to obtain the CoB-NiCoP-Ni3B / MXene catalyst.

2. The method for preparing a catalyst for hydrogen decomposition by water of ammonia borane based on high-efficiency multifunctional active sites according to claim 1, characterized in that: In step (3), the molar ratio of Co(NO3)2·6H2O to Ni(NO3)2·6H2O is 1:

1.

3. The method for preparing a catalyst for hydrogen decomposition by water of ammonia borane based on high-efficiency multifunctional active sites according to claim 1, characterized in that: In step (4), the NaBH4 solution is prepared by dissolving 1900 mg of sodium borohydride in 10 mL of deionized water containing 40 mg of sodium hydroxide and stirring the mixture uniformly; the addition rate of the NaBH4 is 0.6 to 0.8 mL / min.

4. The method for preparing a catalyst for hydrogen decomposition by water of ammonia borane based on high-efficiency multifunctional active sites according to claim 1, characterized in that: In step (5), in the phosphorus induction process, the phosphorus source is NaH2PO2; the mass ratio of the CoB-Ni3B / MXene precursor material to NaH2PO2 is 1:

10.

5. The method for preparing a catalyst for hydrogen decomposition by water of ammonia borane based on high-efficiency multifunctional active sites according to claim 1, characterized in that: In step (5), the heating rate during calcination is 3-10°C / min, the temperature is 250-450°C, and the time is 60-120min.

6. A method for preparing a catalyst for hydrogen decomposition by water using ammonia borane based on high-efficiency multifunctional active sites according to any one of claims 1 to 5, characterized in that: The structure of the catalyst CoB-NiCoP-Ni3B / MXene is that CoB, NiCoP, and Ni3B are in situ grown on a MXene support.

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