Catalyst for producing hydrogen through catalytic decomposition of ammonia borane as well as preparation method and application of catalyst
By preparing the xAg/CoW catalyst, the high cost problem of precious metal catalysts was solved, and efficient borane-ammonia catalytic decomposition to produce hydrogen was achieved under different solvents and NaOH concentrations. It is suitable for a variety of conditions and has good catalytic performance and stability.
Patent Information
- Application Number
- CN202510839415.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-23
- Publication Date
- 2025-10-21
AI Technical Summary
The high cost of catalyzing the decomposition of ammonia borane to produce hydrogen using existing precious metal catalysts limits the industrial application of catalytic decomposition of ammonia borane to produce hydrogen. In addition, existing technologies fail to effectively solve the problem of catalytic decomposition under different solvent systems and NaOH concentration conditions.
The xAg/CoW catalyst was prepared by hydrothermal method and wet impregnation-in situ reduction method. By combining Ag with CoWO4, the xAg/CoW catalyst was formed and used to catalyze the decomposition of borane and ammonia to produce hydrogen in various NaOH concentrations and solvent systems.
The catalyst achieved efficient catalytic decomposition of borane and ammonia to produce hydrogen at a relatively low cost. The catalyst exhibited good cyclic stability and applicability and was suitable for a variety of solvents and NaOH concentration conditions.
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Figure CN120815552A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of catalytic functional materials and hydrogen energy, and particularly relates to a catalyst for hydrogen production by catalytic decomposition of ammonia by borane, and a preparation method and application thereof. Background Art
[0002] In recent years, hydrogen energy has been widely used in fuel cells and other fields as a high-energy clean energy source. The hydrogen storage material ammonia borane has high stability and high hydrogen content. The catalytic decomposition of ammonia borane to produce hydrogen is a promising hydrogen production technology. Under the action of a catalyst, each mole of ammonia borane can be catalytically decomposed in solvents such as water or methanol to produce 3 moles of hydrogen. As the core of the catalytic decomposition of ammonia borane to produce hydrogen, the catalyst is crucial to the reaction performance. At present, the catalytic decomposition of ammonia borane to produce hydrogen by platinum group metal catalysts such as Rh, Ru, Ir, Pt and Pd has been widely studied and has achieved good catalytic hydrogen production performance. However, the scarcity and high cost of precious metals have severely limited the industrial application of the catalytic decomposition of ammonia borane to produce hydrogen. Therefore, there is an urgent need to develop lower-cost catalysts to achieve efficient catalytic decomposition of ammonia borane to produce hydrogen.
[0003] Patent document CN2018102592454 discloses the synthesis of a composite catalyst, SrTiO3 / Ag2S / CoWO4, using a hydrothermal and precipitation method. This catalyst effectively separates the photogenerated electrons and holes. The addition of silver sulfide, acting as a conductive channel, accelerates electron transfer, ultimately resulting in a composite catalyst that has been applied to the degradation of tetracycline antibiotic wastewater, demonstrating high catalytic degradation activity. However, the patent document contains no information regarding the use of a small amount of Ag-loaded CoWO4 catalyst, nor regarding the catalytic decomposition of ammonia borane to produce hydrogen. Summary of the Invention
[0004] Based on the above research background and technical requirements, the present invention provides a catalyst for hydrogen production by catalytic decomposition of ammonia by borane and a preparation method thereof, which is prepared by a hydrothermal method and a wet impregnation-in-situ reduction method. x Ag / CoW catalyst can achieve efficient catalytic decomposition of borane and ammonia to produce hydrogen in different solvent systems. This catalyst can be applied to various NaOH concentration conditions and solvent systems of different compositions, achieving efficient catalytic decomposition of borane and ammonia to produce hydrogen at a relatively low cost, making this technology widely applicable.
[0005] The present invention adopts the following technical solution to solve the above technical problems: a catalyst for catalytic decomposition of ammonia by borane to produce hydrogen, the catalyst is composed of the following components: Ag and CoWO4, wherein the mass ratio of Ag to CoWO4 is x The catalyst can achieve efficient catalytic decomposition of borane and ammonia to produce hydrogen under conditions of low Ag loading ratio, and can be applied to various NaOH concentration conditions and solvent systems of different compositions.
[0006] Furthermore, the specific process of the efficient catalytic decomposition of ammonia borane to produce hydrogen is as follows: ultrasonically dispersing the catalyst in a NaOH solution to obtain a catalyst dispersion, stabilizing the reaction system in a 30°C water bath, and then adding the ammonia borane solution to the catalyst dispersion to form a catalytic reaction system. The concentration of the NaOH solution in the catalytic reaction system is 1-6 mol L −1 The concentration of the catalyst is 5-30 mg L −1 The concentration of borane ammonia is 0.5-3mmol L −1 , ultimately achieving full contact between the catalyst and borane and efficient catalytic degradation of borane.
[0007] The preparation method of the catalyst for hydrogen production by catalytic decomposition of ammonia by borane of the present invention comprises the following specific preparation steps: Step S1, adding cobalt chloride hexahydrate to deionized water and stirring thoroughly to obtain a clear and transparent purple solution A; Step S2, adding sodium tungstate dihydrate into deionized water and stirring thoroughly to obtain a clear and transparent colorless solution B; Step S3, under vigorous stirring, adding the colorless solution B obtained in step S2 dropwise to the purple solution A obtained in step S1, and stirring and mixing thoroughly to obtain a pink-purple suspension C; Step S4, hydrothermally reacting the purple suspension C obtained in step S3 at 120-180° C. for 10-18 hours; Step S5, collecting the blue precipitate obtained after the hydrothermal reaction in step S4 by centrifugation, washing it with deionized water, and drying it at 60-120° C. for 12-24 hours; Step S6, fully grinding the blue precipitate obtained from step S5 and calcining it at 400-600° C. for 2-6 hours to obtain CoWO4 oxide; Step S7, fully dissolving silver nitrate corresponding to the Ag loading ratio in deionized water to obtain a silver nitrate solution; Step S8, adding the CoWO4 oxide obtained in step S6 as a catalyst carrier to the silver nitrate solution obtained in step S7, and mixing by ultrasonication to obtain a gray-black mixed suspension D; Step S9, adding the sodium borohydride solution dropwise to the gray-black mixed suspension D obtained in step S8, and stirring the mixture for 0.5-2 hours after the addition is complete; Step S10, collecting the precipitate obtained in the reaction of step S9 by centrifugation, washing it with deionized water, and drying it at 40-60° C. for 12-24 hours to obtain a catalyst for hydrogen production by catalytic decomposition of ammonia by borane.
[0008] Furthermore, in step S4, the pink-purple suspension C is hydrothermally reacted at 180° C. for 12 h.
[0009] Furthermore, the calcination condition in step S6 is 5°C min −1 The heating rate was from room temperature to 500 °C and calcined at 500 °C for 3 h.
[0010] Furthermore, the concentration of the sodium borohydride solution in step S9 is 0.05-0.2 mol L −1 .
[0011] The catalyst for producing hydrogen by catalytic decomposition of ammonia borane is used for catalytic decomposition of ammonia borane to produce hydrogen.
[0012] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The preparation method of the catalyst for hydrogen production by catalytic decomposition of ammonia borane according to the present invention is simple and low-cost, which facilitates industrial-scale scale-up production and its practical application in the field of hydrogen production by catalytic decomposition of ammonia borane.
[0013] 2. The test conditions for the performance of the catalytic decomposition of ammonia by borane to produce hydrogen in the present invention are: at a reaction temperature of 30°C, a catalyst concentration range of 5-30 mg L −1 , NaOH solution concentration range is 1-6 mol L −1 The concentration of borane ammonia is in the range of 0.5-3 mmol L −1 , all showed good catalytic decomposition efficiency of borane ammonia to produce hydrogen, and still showed good catalytic hydrogen production performance at lower catalyst concentrations. x The Ag / CoW catalyst showed good cyclic stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 For different Ag loading ratios x Efficiency of hydrogen production from catalytic decomposition of ammonia borane over Ag / CoW catalyst.
[0015] Figure 2 The efficiency of hydrogen production from the catalytic decomposition of ammonia by borane at different 3% Ag / CoW catalyst concentrations.
[0016] Figure 3 The efficiency of hydrogen production from borane-ammonia catalytic decomposition over 3% Ag / CoW catalyst at different NaOH concentrations.
[0017] Figure 4 The efficiency of hydrogen production from the catalytic decomposition of ammonia borane over 3% Ag / CoW catalyst at different ammonia borane dosages.
[0018] Figure 5 The efficiency of hydrogen production from the catalytic decomposition of ammonia by borane over 3% Ag / CoW catalyst in different solvent systems. DETAILED DESCRIPTION
[0019] The above contents of the present invention are further described in detail below through examples, but this should not be understood as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above contents of the present invention fall within the scope of the present invention. Example 1
[0020] Preparation of catalyst: Add 2 mmol of cobalt chloride hexahydrate and 2 mmol of sodium tungstate dihydrate to 30 mL of deionized water, stir vigorously and mix well to obtain cobalt nitrate hexahydrate solution and sodium tungstate dihydrate solution, respectively. Add sodium tungstate dihydrate solution dropwise to cobalt nitrate hexahydrate solution and react fully to obtain a pink-purple suspension. Transfer the pink-purple suspension into the polytetrafluoroethylene liner of the reactor and perform hydrothermal reaction in an electric oven at 180°C for 12 hours. Centrifuge the precipitate obtained after the hydrothermal reaction, wash with deionized water, and transfer to a constant temperature oven at 60°C for drying for 12 hours. Grind the dried product thoroughly and refrigerate at 5°C min −1 The temperature was raised to 500℃ at a heating rate and calcined at 500℃ for 3h to obtain CoWO4 oxide. Silver nitrate corresponding to a mass ratio of 1% of Ag loading was dissolved in water to obtain a silver nitrate solution. CoWO4 oxide was added to the silver nitrate solution as a catalyst support, and ultrasonic treatment was performed for 15min and then stirred for 3h to obtain a gray-black mixed suspension. Subsequently, 0.1mol L −1 The sodium borohydride solution was added dropwise to the gray-black mixed suspension. After the addition was complete, the reaction was stirred thoroughly for 1 hour. The resulting precipitate was collected by centrifugation, washed with deionized water, and dried in a 60°C vacuum oven for 12 hours to obtain a 1% Ag / CoW catalyst for the catalytic decomposition of borane and ammonia for hydrogen production with a 1wt% Ag loading. A CoWO4 catalyst was prepared using the same procedure without the addition of silver nitrate.
[0021] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, ensuring full contact between the catalyst and borane and catalytic reaction. The specific conditions are as follows: in the aqueous reaction system, the amount of 1% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 2 mol L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 1As shown in the figure, under the action of 1% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol hydrogen in 16.9 minutes, which is a significant improvement over the CoWO4 catalyst. Example 2
[0022] Preparation of catalyst: 2 mmol of cobalt chloride hexahydrate and 2 mmol of sodium tungstate dihydrate of the corresponding metal element were added to 30 mL of deionized water, and stirred vigorously to obtain cobalt nitrate hexahydrate solution and sodium tungstate dihydrate solution, respectively. Add the sodium tungstate dihydrate solution dropwise to the cobalt nitrate hexahydrate solution, and obtain a pink-purple suspension after sufficient reaction. Transfer the pink-purple suspension into the polytetrafluoroethylene liner of the reactor and perform hydrothermal reaction in an electric oven at 180°C for 12 hours. The precipitate obtained after the hydrothermal reaction was centrifuged, washed with deionized water, and then transferred to a constant temperature oven at 60°C for drying for 12 hours. After the dried product was fully ground, it was refrigerated at 5°C min −1 The temperature was raised to 500℃ at a heating rate and calcined at 500℃ for 3h to obtain CoWO4 oxide. Silver nitrate corresponding to a 3% Ag loading mass ratio was dissolved in water to obtain a silver nitrate solution. CoWO4 oxide was added as a catalyst support to the silver nitrate solution and ultrasonically treated for 15min to obtain a gray-black mixed suspension. Subsequently, 0.1mol L −1 The sodium borohydride solution was added dropwise to the gray-black mixed suspension. After complete addition, the reaction was stirred thoroughly for 1 hour. The resulting precipitate was collected by centrifugation, washed with deionized water, and dried in a vacuum oven at 60°C for 12 hours to obtain a 3% Ag / CoW catalyst for the catalytic decomposition of borane and ammonia for hydrogen production. The same procedure was followed without the addition of silver nitrate to prepare a CoWO4 catalyst. The 3% Ag / TiO2 catalyst was obtained by replacing the CoWO4 support with TiO2 and repeating the Ag loading procedure.
[0023] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 2 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 1As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol hydrogen in 12.0 minutes, which is a significant improvement over both CoWO4 and 3% Ag / TiO2 catalysts. Example 3
[0024] Preparation of catalyst: 2 mmol of cobalt chloride hexahydrate and 2 mmol of sodium tungstate dihydrate of the corresponding metal element were added to 30 mL of deionized water respectively, and stirred vigorously to obtain a cobalt nitrate hexahydrate solution and a sodium tungstate dihydrate solution. The sodium tungstate dihydrate solution was added dropwise to the cobalt nitrate hexahydrate solution, and a pink-purple suspension was obtained after sufficient reaction. The pink-purple suspension was transferred to the polytetrafluoroethylene liner of the reactor and subjected to hydrothermal reaction in an electric oven at a temperature of 180°C for 12 hours. The precipitate obtained after the hydrothermal reaction was centrifuged, washed with deionized water, and then transferred to a constant temperature oven at 60°C for drying for 12 hours. The dried product was fully ground and refrigerated at 5°C min −1 The temperature was raised to 500℃ at a heating rate and calcined at 500℃ for 3h to obtain CoWO4 oxide. Silver nitrate corresponding to a 5% Ag loading mass ratio was dissolved in water to obtain a silver nitrate solution. CoWO4 oxide was added to the silver nitrate solution as a catalyst support and ultrasonically treated for 15min to obtain a gray-black mixed suspension. Subsequently, 0.1mol L −1 A sodium borohydride solution was added dropwise to the gray-black mixed suspension. After complete addition, the reaction was stirred thoroughly for 1 hour. The resulting precipitate was collected by centrifugation, washed with deionized water, and dried in a 60°C vacuum oven for 12 hours to obtain a 5% Ag / CoW catalyst for hydrogen production from the decomposition of ammonia by borane with a 5wt% Ag loading. A CoWO4 catalyst was prepared using the same procedure without the addition of silver nitrate.
[0025] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 5% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 2 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 1 As shown in the figure, under the action of 5% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol hydrogen in 11.4 minutes, which is a significant improvement over the CoWO4 catalyst. Example 4
[0026] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0027] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, ensuring sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 5 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 2 mol L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 2 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen in 23.2 minutes. Example 5
[0028] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0029] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 20 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 2 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 2 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen in 8.5 minutes, and the reaction performance is significantly improved compared with the cases when the catalyst dosage is 5 and 10 mg. Example 6
[0030] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0031] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 30 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 2 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 2 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen in 5.5 minutes, and the reaction performance is significantly improved compared with the catalyst dosage of 5, 10 and 20 mg. Example 7
[0032] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0033] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized under water bath conditions, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 1 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 3 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia was completely decomposed to produce 3 mmol of hydrogen within 25.5 minutes. Example 8
[0034] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0035] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 4 mol / L −1The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 3 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen within 9.4 minutes. Example 9
[0036] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0037] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 1 mmol, and the NaOH solution concentration is 6 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 3 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen within 6.7 minutes. Example 10
[0038] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0039] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, ensuring sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 0.5 mmol, and the NaOH solution concentration is 2 mol L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 4 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 1.5 mmol hydrogen within 8.8 minutes. Example 11
[0040] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0041] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 2 mmol, and the NaOH solution concentration is 2 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 4 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 6 mmol hydrogen within 15.0 minutes. Example 12
[0042] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0043] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, so as to achieve sufficient contact and reaction between the catalyst and borane. The specific conditions are as follows: in the aqueous reaction system, the amount of 3% Ag / CoW catalyst is 10 mg, the reaction temperature is 30°C, the borane content is 3 mmol, and the NaOH solution concentration is 2 mol / L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 4 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 9 mmol hydrogen within 12.7 minutes. Example 13
[0044] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0045] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, ensuring sufficient contact and reaction between the catalyst and borane. Specific conditions are as follows: the solvent volume ratio in the reaction system is water:methanol = 4:1, the amount of 3% Ag / CoW catalyst is 10mg, the reaction temperature is 30°C, the borane content is 1mmol, and the NaOH solution concentration is 2mol L −1The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 5 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen within 10.1 minutes. Example 14
[0046] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0047] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, ensuring sufficient contact and reaction between the catalyst and borane. Specific conditions are as follows: the solvent volume ratio in the reaction system is water:methanol = 2:1, the amount of 3% Ag / CoW catalyst is 10mg, the reaction temperature is 30°C, the borane content is 1mmol, and the NaOH solution concentration is 2mol L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 5 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen within 7.4 minutes. Example 15
[0048] Preparation of catalyst: The preparation process of the catalyst in this example is consistent with that in Example 2.
[0049] Catalyst performance test: A certain amount of catalyst is dispersed in a certain concentration of NaOH solution. After the reaction system is sealed and the temperature is stabilized in a water bath, a corresponding amount of borane solution is added to the catalyst dispersion to initiate the reaction, ensuring sufficient contact and reaction between the catalyst and borane. Specific conditions are as follows: the solvent volume ratio in the reaction system is water:methanol = 1:1, the amount of 3% Ag / CoW catalyst is 10mg, the reaction temperature is 30°C, the borane content is 1mmol, and the NaOH solution concentration is 2mol L −1 The amount of hydrogen produced was measured by the water displacement method, the time for the corresponding volume of hydrogen production was recorded, and the performance of the catalytic decomposition of ammonia by borane to produce hydrogen was comprehensively evaluated. Figure 5 As shown in the figure, under the action of 3% Ag / CoW catalyst, borane ammonia can be completely decomposed to produce 3 mmol of hydrogen within 10.0 minutes.
[0050] The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the scope of the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.
Claims
1. A catalyst for hydrogen production by catalytic decomposition of ammonia and borane, characterized in that The catalyst consists of the following components: Ag and CoWO4, wherein the mass ratio of Ag to CoWO4 is x The catalyst can achieve efficient catalytic decomposition of borane ammonia to produce hydrogen under the condition of a relatively low Ag loading ratio, and can be applied to a variety of NaOH concentration conditions and solvent systems with different compositions.
2. The catalyst for hydrogen production by catalytic decomposition of ammonia by borane according to claim 1, characterized in that The specific process of the high-efficiency catalytic decomposition of ammonia borane to produce hydrogen is as follows: ultrasonically dispersing the catalyst in a NaOH solution to obtain a catalyst dispersion, stabilizing the reaction system in a 30°C water bath, and then adding the ammonia borane solution to the catalyst dispersion to form a catalytic reaction system. The concentration of the NaOH solution in the catalytic reaction system is 1-6 mol L −1 The concentration of the catalyst is 5-30 mg L −1 The concentration of borane ammonia is 0.5-3mmol L −1 , ultimately achieving full contact between the catalyst and borane and efficient catalytic degradation of borane.
3. A method for preparing the catalyst for hydrogen production by catalytic decomposition of ammonia by borane according to claim 1 or 2, characterized in that The specific preparation steps are: Step S1, adding cobalt chloride hexahydrate to deionized water and stirring thoroughly to obtain a clear and transparent purple solution A; Step S2, adding sodium tungstate dihydrate into deionized water and stirring thoroughly to obtain a clear and transparent colorless solution B; Step S3, under vigorous stirring, adding the colorless solution B obtained in step S2 dropwise to the purple solution A obtained in step S1, and stirring and mixing thoroughly to obtain a pink-purple suspension C; Step S4, hydrothermally reacting the purple suspension C obtained in step S3 at 120-180° C. for 10-18 hours; Step S5, collecting the blue precipitate obtained after the hydrothermal reaction in step S4 by centrifugation, washing it with deionized water, and drying it at 60-120° C. for 12-24 hours; Step S6, fully grinding the blue precipitate obtained from step S5 and calcining it at 400-600° C. for 2-6 hours to obtain CoWO4 oxide; Step S7, fully dissolving silver nitrate corresponding to the Ag loading ratio in deionized water to obtain a silver nitrate solution; Step S8, adding the CoWO4 oxide obtained in step S6 as a catalyst carrier to the silver nitrate solution obtained in step S7, and mixing by ultrasonication to obtain a gray-black mixed suspension D; Step S9, adding the sodium borohydride solution dropwise to the gray-black mixed suspension D obtained in step S8, and stirring the mixture for 0.5-2 hours after the addition is complete; Step S10, collecting the precipitate obtained in the reaction of step S9 by centrifugation, washing it with deionized water, and drying it at 40-60° C. for 12-24 hours to obtain a catalyst for hydrogen production by catalytic decomposition of ammonia by borane.
4. The method for preparing the catalyst for hydrogen production by catalytic decomposition of ammonia by borane according to claim 3, characterized in that: In step S4, the pink-purple suspension C is hydrothermally reacted at 180° C. for 12 h.
5. The method for preparing the catalyst for hydrogen production by catalytic decomposition of ammonia by borane according to claim 3, wherein: The calcination conditions in step S6 are 5°C min −1 The heating rate was from room temperature to 500 °C and calcined at 500 °C for 3 h.
6. The method for preparing the catalyst for hydrogen production by catalytic decomposition of ammonia by borane according to claim 3, wherein: The concentration of the sodium borohydride solution in step S9 is 0.05-0.2 mol L −1 .
7. The catalyst for producing hydrogen by catalytic decomposition of ammonia borane according to claim 1 or 2 is used for catalytic decomposition of ammonia borane to produce hydrogen.