A method for preparing a catalyst for improving the amount of hydrogen released by nano-aluminum hydrolysis and a catalyst

Abstract

The invention discloses a method for preparing a catalyst that improves the amount of hydrogen released by nano-aluminum hydrolysis, including: step 1, prepares mixed graphene; step 2, cobalt chloride is mixed with mixed graphene in proportion and ball-milled in a planetary ball mill to obtain graphene-supported cobalt chloride; step 3, the graphene-supported cobalt chloride is mixed with sodium borohydride ball milling; step 4, the powder obtained by step 3 is added to the aqueous solution of sodium hydroxide, hydrolysis reaction 1 10min is carried out under the conditions of 25 30 DEG C, and the reaction product is dried in a vacuum drying oven after filtering, and drying temperature is room temperature, and drying time is 24 36h, and the Co B catalyst of mixed graphene support is obtained. The present invention prepares catalyst by preparing after mixed graphene, so that when carrying out hydrolysis and hydrogen release, hydrogen release rate can be improved while increasing hydrogen release amount, and reaction controllability is enhanced while improving reaction rate.

Description

Technical Field

[0001] The invention belongs to the field of hydrogen storage materials, and particularly relates to a method for preparing a catalyst for improving the amount of hydrogen released by hydrolysis of nano-aluminum and the catalyst. Background Art

[0002] Aluminum is abundant in the Earth's crust, accounting for approximately 7.45% of its total weight. Aluminum possesses relatively active chemical properties due to its 3S23P1 electrical layer structure. Its corrosion potential is -1.662V, and it can undergo self-corrosion reactions in water. The theoretical hydrogen release rates of reactive metals such as sodium, magnesium, and iron when reacting with water are 4.34%, 8.3%, and 3.57%, respectively. The hydrogen release rate of the aluminum-water reaction is 11.1%, which is higher than that of reactive metals such as sodium, magnesium, and iron. Furthermore, the reaction between aluminum and water is exothermic and spontaneous, and the generated Al(OH)3 can be recycled to produce elemental aluminum. Therefore, hydrogen production from Al hydrolysis has the advantages of low cost and environmental friendliness, and has good development prospects.

[0003] For many years, scholars have conducted extensive and in-depth research on the hydrolysis of aluminum to produce hydrogen. During the aluminum hydrolysis reaction, an oxide film forms on the aluminum surface as the reaction proceeds, hindering further reaction. Through research, scholars have identified five methods to break down the oxide film and thereby accelerate the aluminum-hydrogen reaction rate. These methods are: removing the oxide film through OH-, combining aluminum with metal oxides, combining aluminum with inorganic salts, forming alloys with other metals, and combining aluminum with hydrides.

[0004] However, although the above method can improve the performance of hydrolysis hydrogen production to a certain extent, its hydrogen production efficiency is still low. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a method for preparing a catalyst and a catalyst for improving the amount of hydrogen released by the hydrolysis of nano-aluminum. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0006] A method for preparing a catalyst for increasing the amount of hydrogen released by hydrolysis of nano-aluminum comprises:

[0007] Step 1, preparing hybrid graphene;

[0008] Step 2, mixing cobalt chloride and mixed graphene in proportion and ball milling them in a planetary ball mill to obtain graphene-supported cobalt chloride;

[0009] Step 3, ball-milling the graphene-supported cobalt chloride and sodium borohydride;

[0010] Step 4: adding the powder obtained in step 3 to an aqueous solution of sodium hydroxide, performing a hydrolysis reaction at 25-30° C. for 1-10 minutes, filtering the reaction product and drying it in a vacuum drying oven at room temperature for 24-36 hours to obtain a mixed graphene-supported Co-B catalyst.

[0011] In one embodiment, step 1 comprises:

[0012] A. Divide the cobalt chloride sample into three equal parts and mix them with the same mass of one-dimensional graphene, two-dimensional graphene, and three-dimensional graphene, respectively, to obtain a first sample, a second sample, and a third sample;

[0013] B. ball milling the first sample, the second sample, and the third sample in a planetary ball mill;

[0014] C. ball-milling the first sample powder, the second sample powder, and the third sample powder with sodium borohydride to obtain a first mixed sample powder, a second mixed sample powder, and a third mixed sample powder;

[0015] D. Add the powder obtained in step C to an aqueous solution of sodium hydroxide, respectively, and perform a hydrolysis reaction at 25-30° C. for 1-10 min. After filtering the reaction product, dry it in a vacuum drying oven at room temperature for 24-36 h to obtain a one-dimensional graphene-supported Co-B catalyst sample, a two-dimensional graphene-supported Co-B catalyst sample, and a three-dimensional graphene-supported Co-B catalyst sample;

[0016] E. Adding the one-dimensional graphene-supported Co-B catalyst sample, the two-dimensional graphene-supported Co-B catalyst sample, and the three-dimensional graphene-supported Co-B catalyst sample to an alkaline aqueous solution of nanoaluminum of the same concentration and volume to perform a hydrogen desorption test, collecting a preset number of hydrogen desorption time points and hydrogen desorption rate values within the starting collection time point and the ending collection time point, and fitting the hydrogen desorption time points and hydrogen desorption rate values with the hydrogen desorption time as the abscissa and the hydrogen desorption rate as the ordinate to obtain a first hydrogen desorption fitting curve, a second hydrogen desorption fitting curve, and a third hydrogen desorption fitting curve;

[0017] F. Using the time corresponding to the maximum hydrogen desorption rate value in the hydrogen desorption fitting curve as a dividing line, calculating the ratio of the area from the start time of collection to the time corresponding to the maximum value to the area from the time corresponding to the maximum value to the end time of collection, and obtaining a first parameter corresponding to one-dimensional graphene, a second parameter corresponding to two-dimensional graphene, and a third parameter corresponding to three-dimensional graphene according to the first hydrogen desorption fitting curve, the second hydrogen desorption fitting curve, and the third hydrogen desorption fitting curve in sequence;

[0018] G. Normalizing the first parameter, the second parameter, and the third parameter, and preparing the hybrid graphene according to the normalized ratio.

[0019] In one embodiment, the mass ratio of the ball-milled powder to the grinding balls in step 2 is 1:20-40, the grinding balls are made of stainless steel, and the ball milling time is 20-40 min.

[0020] In one embodiment, the ball milling time in step 3 is 20-40 min, the mass ratio of ball mill powder to grinding balls is 1:20-40, and the grinding balls are made of alumina.

[0021] In a specific embodiment, the mass ratio of cobalt chloride to mixed graphene is 10:0.1-1.

[0022] In a specific embodiment, the mass ratio of the graphene-supported cobalt chloride to sodium borohydride is 1:0.1-6.

[0023] In one embodiment, the pH value of the aqueous solution of sodium hydroxide in step 4 is 9-11.

[0024] In one specific embodiment, the mass ratio of the one-dimensional graphene-supported Co-B catalyst sample, the two-dimensional graphene-supported Co-B catalyst sample, the three-dimensional graphene-supported Co-B catalyst sample and the nano-aluminum is 1:10-50, and the pH value of the alkaline aqueous solution of the nano-aluminum is 9-11.

[0025] The present invention also provides a catalyst for increasing the amount of hydrogen released by the hydrolysis of nano-aluminum. The catalyst is prepared by the above-mentioned method for preparing the catalyst for increasing the amount of hydrogen released by the hydrolysis of nano-aluminum.

[0026] Beneficial effects of the present invention:

[0027] The catalyst preparation method for improving the amount of hydrogen released by hydrolysis of nano-aluminum of the present invention analyzes the combination and reaction conditions of the catalyst on one-dimensional, two-dimensional and three-dimensional graphene supports, determines the optimal parameters of the three, mixes the three according to the optimal parameters to form mixed graphene, and then prepares the catalyst. When performing hydrolysis hydrogen release, the hydrogen release amount can be increased while the hydrogen release rate is improved, and the reaction controllability can be enhanced while the reaction rate is increased.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic flow chart of a preparation method for improving the performance of AB-type hydrogen storage alloys provided in an embodiment of the present invention.

[0030] Figure 23 is a comparison diagram of hydrogen release curves provided in the examples. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0032] Example 1

[0033] See Figure 1 , Figure 1 The present invention provides a method for preparing an AB-type hydrogen storage alloy to improve its performance, which includes:

[0034] A method for preparing a catalyst for increasing the amount of hydrogen released by hydrolysis of nano-aluminum, comprising:

[0035] Step 1, preparing hybrid graphene;

[0036] Specifically, this step includes:

[0037] A. Divide the cobalt chloride sample into three equal parts and mix them with the same mass of one-dimensional graphene, two-dimensional graphene, and three-dimensional graphene, respectively, to obtain a first sample, a second sample, and a third sample;

[0038] B. ball milling the first sample, the second sample, and the third sample in a planetary ball mill;

[0039] C. ball-milling the first sample powder, the second sample powder, and the third sample powder with sodium borohydride to obtain a first mixed sample powder, a second mixed sample powder, and a third mixed sample powder;

[0040] D. Add the powder obtained in step C to an aqueous solution of sodium hydroxide, respectively, and perform a hydrolysis reaction at 25-30° C. for 1-10 min. After filtering the reaction product, dry it in a vacuum drying oven at room temperature for 24-36 h to obtain a one-dimensional graphene-supported Co-B catalyst sample, a two-dimensional graphene-supported Co-B catalyst sample, and a three-dimensional graphene-supported Co-B catalyst sample;

[0041] E. Adding a one-dimensional graphene-supported Co-B catalyst sample, a two-dimensional graphene-supported Co-B catalyst sample, and a three-dimensional graphene-supported Co-B catalyst sample to an alkaline aqueous solution of nanoaluminum of the same concentration and volume to perform a hydrogen desorption test, collecting a preset number of hydrogen desorption time and hydrogen desorption rate values within the starting collection time and the ending collection time, and fitting the hydrogen desorption time and hydrogen desorption rate values with the hydrogen desorption time as the horizontal axis and the hydrogen desorption rate as the vertical axis to obtain a first hydrogen desorption fitting curve, a second hydrogen desorption fitting curve, and a third hydrogen desorption fitting curve; in this step, the mass ratio of the one-dimensional graphene-supported Co-B catalyst sample, the two-dimensional graphene-supported Co-B catalyst sample, and the three-dimensional graphene-supported Co-B catalyst sample to the nanoaluminum is 1:10-50, and the pH value of the alkaline aqueous solution of the nanoaluminum is 9-11.

[0042] It should be noted that, since the reactants have the same mass, the hydrogen release amounts of the three are theoretically the same. That is, the areas enclosed by the first, second, and third hydrogen release fitting curves are theoretically consistent. However, in actual production applications, the hydrogen release rate generally needs to be controlled, and the curve in the late reaction period is too smooth, while the rising curve in the early reaction period is too steep. Therefore, in this example, the reaction parameters from 5 to 35 minutes are selected for statistical analysis, i.e., the starting time for collection is the 5th minute (inclusive); four records are recorded per minute, i.e., 120 hydrogen release moments are statistically analyzed for curve fitting with the hydrogen release rate values.

[0043] F. Using the time corresponding to the maximum hydrogen desorption rate value in the hydrogen desorption fitting curve as a dividing line, calculating the ratio of the area from the start time of collection to the time corresponding to the maximum value to the area from the time corresponding to the maximum value to the end time of collection, and obtaining a first parameter corresponding to one-dimensional graphene, a second parameter corresponding to two-dimensional graphene, and a third parameter corresponding to three-dimensional graphene according to the first hydrogen desorption fitting curve, the second hydrogen desorption fitting curve, and the third hydrogen desorption fitting curve in sequence;

[0044] G. Normalizing the first parameter, the second parameter, and the third parameter, and preparing the hybrid graphene according to the normalized ratio.

[0045] Step 2: Cobalt chloride and mixed graphene are mixed in a suitable proportion and ball-milled in a planetary ball mill to obtain graphene-supported cobalt chloride. Preferably, the mass ratio of the ball-milled powder to the grinding balls is 1:20-40, the grinding balls are made of stainless steel, and the ball milling time is 20-40 minutes. Preferably, the mass ratio of cobalt chloride to mixed graphene is 10:0.1-1.

[0046] Step 3: ball-milling the graphene-supported cobalt chloride and sodium borohydride. Preferably, the ball milling time is 20-40 minutes, the mass ratio of the milled powder to the grinding balls is 1:20-40, and the grinding balls are made of alumina. Preferably, the mass ratio of the graphene-supported cobalt chloride to sodium borohydride is 1:0.1-6.

[0047] Step 4: adding the powder obtained in step 3 to an aqueous solution of sodium hydroxide, performing a hydrolysis reaction at 25-30° C. for 1-10 minutes, filtering the reaction product and drying it in a vacuum drying oven at room temperature for 24-36 hours to obtain a mixed graphene-supported Co-B catalyst.

[0048] Preferably, the pH value of the aqueous solution of sodium hydroxide in step 4 is 9-11.

[0049] Example 1

[0050] Step 1: First, prepare hybrid graphene.

[0051] (1) Preparation of graphene-supported Co-B catalyst samples. Weigh 0.3 g of cobalt chloride sample and divide it into three portions, each weighing 0.1 g. Weigh 0.05 g of one-dimensional graphene, two-dimensional graphene, and three-dimensional graphene, respectively, and mix them with the cobalt chloride sample. Each of these was prepared as follows: ball milling was performed in a planetary ball mill with a mass ratio of ball mill powder to stainless steel grinding balls of 1:20, i.e., 0.35 g:7 g. The ball-milled powder was then mixed with sodium borohydride ball mill at a corresponding mass ratio of 1:10, the ball milling time was 20 minutes, and the mass ratio of the ball-milled powder to the alumina grinding balls was 1:20; the mixed powder was added to an aqueous solution of sodium hydroxide and hydrolyzed at 25°C for 5 minutes. The reaction product was filtered and dried in a vacuum drying oven at room temperature for 24 hours, thereby preparing one-dimensional graphene-loaded Co-B catalyst samples, two-dimensional graphene-loaded Co-B catalyst samples, and three-dimensional graphene-loaded Co-B catalyst samples.

[0052] (2) Calculation of the ratio of the mixed graphene-loaded Co-B catalyst. According to the mass ratio of the catalyst sample to the nano-aluminum of 1:50, the one-dimensional graphene-loaded Co-B catalyst sample, the two-dimensional graphene-loaded Co-B catalyst sample, and the three-dimensional graphene-loaded Co-B catalyst sample were added to the alkaline aqueous solution of the nano-aluminum with the same concentration and volume for hydrogen desorption test, and the measurement was performed by the water displacement method. With 5 minutes as the starting time of collection and 35 minutes as the ending time of collection, 120 hydrogen desorption times and hydrogen desorption rate values (i.e., the amount of hydrogen desorption per unit time) were collected. The hydrogen desorption time and hydrogen desorption rate values were fitted with the hydrogen desorption time as the horizontal axis and the hydrogen desorption rate as the vertical axis to obtain the first hydrogen desorption fitting curve, the second hydrogen desorption fitting curve, and the third hydrogen desorption fitting curve. The time corresponding to the maximum hydrogen desorption rate value in the hydrogen desorption fitting curve is used as a dividing line, and the ratio of the area from the start acquisition time to the time corresponding to the maximum value to the area from the time corresponding to the maximum value to the end acquisition time is calculated (for example, the area ratio is 5:8:10). According to the first hydrogen desorption fitting curve, the second hydrogen desorption fitting curve, and the third hydrogen desorption fitting curve, a first parameter corresponding to one-dimensional graphene, a second parameter corresponding to two-dimensional graphene, and a third parameter corresponding to three-dimensional graphene are sequentially obtained; the first parameter, the second parameter, and the third parameter are normalized (i.e., 1:1.6:2), and a hybrid graphene is prepared according to the normalized ratio, where the hybrid graphene includes 1 part one-dimensional graphene, 1.6 parts two-dimensional graphene, and 2 parts three-dimensional graphene.

[0053] Step 2: Prepare a mixed graphene-supported Co-B catalyst in a ratio of 1:1.6:2.

[0054] Cobalt chloride and mixed graphene are mixed in a mass ratio of 1:0.5 and ball-milled in a planetary ball mill. The mass ratio of ball-milled powder to grinding balls is 1:20. The grinding balls are made of stainless steel and the ball milling time is 20-40 min. The ball-milled powder is then mixed with sodium borohydride in a mass ratio of 1:10. The ball milling time is 20 min. The mass ratio of ball-milled powder to grinding balls is 1:20. The grinding balls are made of aluminum oxide. (3) The mixed powder is added to an aqueous solution of sodium hydroxide and hydrolyzed at 25°C for 5 min. The reaction product is filtered and dried in a vacuum drying oven at room temperature for 24 h to obtain a Co-B catalyst loaded with mixed graphene.

[0055] Step 3: Measure the amount of hydrogen released by the water displacement method.

[0056] The hybrid graphene-supported Co-B catalyst was added to an alkaline aqueous solution of nanoaluminum at a mass ratio of 1:50. The reaction was carried out at room temperature. The volume of hydrogen produced was measured by the water displacement method. Figure 2 , Figure 2 Curve 1 is the hydrogen desorption curve when only three-dimensional graphene is added, curve 3 is the hydrogen desorption curve when no catalyst is added, curve 2 is the hydrogen desorption curve when the mixed graphene-supported Co-B catalyst of this embodiment is added, and curve 4 is the hydrogen desorption curve when only one-dimensional graphene is added.

[0057] It can be clearly seen that the dehydrogenation amount after adding catalyst is all much higher than the dehydrogenation amount without adding catalyst, and the dehydrogenation curve of only adding three-dimensional graphene has just reached very high reaction speed at the beginning of reaction, and early stage reaction causes reaction process to be difficult to control too fast, and because reaction early stage gas purity is relatively low, therefore, hydrogen quality is relatively low, and later stage reaction is too gentle, causes overall utilization rate to be also relatively low.The dehydrogenation curve of only adding one-dimensional graphene is maintained at a relatively low level in the early stage reaction rate, but there is no improvement in the middle and late stages of reaction, and the whole dehydrogenation cycle is gentle and maintains a relatively low level.And the dehydrogenation curve of the Co-B catalyst adding the present embodiment mixed graphene load is maintained at a relatively low level in the early stage reaction rate, so that when reaction early stage gas purity is relatively low, it will not be because of the too high waste reaction raw materials of reaction rate, and in mid-term (10-25 minute), there will be a significant increase in rate, dehydrogenation rate can maintain a higher level for a long time, and controllability is strong.

[0058] The catalyst preparation method of this embodiment for improving the amount of hydrogen released by hydrolysis of nano-aluminum is prepared by analyzing the combination and reaction of the catalyst on one-dimensional, two-dimensional, and three-dimensional graphene supports, determining the optimal parameters of the three, and mixing the three according to the optimal parameters to form a mixed graphene, so that when hydrolysis is carried out, the amount of hydrogen released can be increased while the hydrogen release rate is improved, and the reaction controllability can be enhanced while the reaction rate is increased.

[0059] This embodiment also provides a catalyst for increasing the amount of hydrogen released by the hydrolysis of nano-aluminum. The catalyst is prepared by the above-mentioned method for preparing a catalyst for increasing the amount of hydrogen released by the hydrolysis of nano-aluminum.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0061] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0062] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art can understand and implement other changes to the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0063] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst to improve the amount of hydrogen released by hydrolysis of nano-aluminum, characterized in that: include: Step 1, preparing hybrid graphene; Step 2, mixing cobalt chloride and mixed graphene in proportion and ball milling them in a planetary ball mill to obtain graphene-supported cobalt chloride; Step 3, ball-milling the graphene-supported cobalt chloride and sodium borohydride; Step 4: adding the powder obtained in step 3 to an aqueous solution of sodium hydroxide, performing a hydrolysis reaction at 25-30° C. for 1-10 min, filtering the reaction product and drying it in a vacuum drying oven at room temperature for 24-36 h to obtain a mixed graphene-supported Co-B catalyst; The step 1 comprises: A. Divide the cobalt chloride sample into three equal parts and mix them with the same mass of one-dimensional graphene, two-dimensional graphene, and three-dimensional graphene, respectively, to obtain a first sample, a second sample, and a third sample; B. ball milling the first sample, the second sample, and the third sample in a planetary ball mill; C. ball-milling the first sample powder, the second sample powder, and the third sample powder with sodium borohydride to obtain a first mixed sample powder, a second mixed sample powder, and a third mixed sample powder; D. Add the powder obtained in step C to an aqueous solution of sodium hydroxide, respectively, and perform a hydrolysis reaction at 25-30° C. for 1-10 min. After filtering the reaction product, dry it in a vacuum drying oven at room temperature for 24-36 h to obtain a one-dimensional graphene-supported Co-B catalyst sample, a two-dimensional graphene-supported Co-B catalyst sample, and a three-dimensional graphene-supported Co-B catalyst sample; E. Adding the one-dimensional graphene-supported Co-B catalyst sample, the two-dimensional graphene-supported Co-B catalyst sample, and the three-dimensional graphene-supported Co-B catalyst sample to an alkaline aqueous solution of nanoaluminum of the same concentration and volume to perform a hydrogen desorption test, collecting a preset number of hydrogen desorption time points and hydrogen desorption rate values within the starting collection time point and the ending collection time point, and fitting the hydrogen desorption time points and hydrogen desorption rate values with the hydrogen desorption time point as the abscissa and the hydrogen desorption rate point as the ordinate to obtain a first hydrogen desorption fitting curve, a second hydrogen desorption fitting curve, and a third hydrogen desorption fitting curve; F. Using the time corresponding to the maximum hydrogen desorption rate value in the hydrogen desorption fitting curve as a dividing line, calculating the ratio of the area from the start time of collection to the time corresponding to the maximum value to the area from the time corresponding to the maximum value to the end time of collection, and obtaining a first parameter corresponding to one-dimensional graphene, a second parameter corresponding to two-dimensional graphene, and a third parameter corresponding to three-dimensional graphene according to the first hydrogen desorption fitting curve, the second hydrogen desorption fitting curve, and the third hydrogen desorption fitting curve in sequence; G. Normalizing the first parameter, the second parameter, and the third parameter, and mixing the one-dimensional graphene, the two-dimensional graphene, and the three-dimensional graphene according to the normalized ratio to prepare the mixed graphene.

2. The method for preparing a catalyst for improving the amount of hydrogen released by hydrolysis of nano-aluminum according to claim 1, characterized in that: In step 2, the mass ratio of the ball-milled powder to the grinding balls is 1:20-40, the grinding balls are made of stainless steel, and the ball-milling time is 20-40 minutes.

3. The method for preparing a catalyst for improving the amount of hydrogen released by hydrolysis of nano-aluminum according to claim 1, characterized in that: In step 3, the ball milling time is 20-40 min, the mass ratio of the ball milled powder to the grinding balls is 1:20-40, and the material of the grinding balls is alumina.

4. The method for preparing a catalyst for improving the amount of hydrogen released by hydrolysis of nano-aluminum according to claim 1, characterized in that: The mass ratio of cobalt chloride to mixed graphene is 10:0.1-1.

5. The method for preparing a catalyst for improving the amount of hydrogen released by hydrolysis of nano-aluminum according to claim 1, characterized in that: The mass ratio of the graphene-supported cobalt chloride to sodium borohydride is 1:0.1-6.

6. The method for preparing a catalyst for improving the amount of hydrogen released by hydrolysis of nano-aluminum according to claim 1, characterized in that: The pH value of the aqueous solution of sodium hydroxide in step 4 is 9-11.

7. The method for preparing a catalyst for improving the amount of hydrogen released by hydrolysis of nano-aluminum according to claim 1, characterized in that: The mass ratio of the one-dimensional graphene-supported Co-B catalyst sample, the two-dimensional graphene-supported Co-B catalyst sample, the three-dimensional graphene-supported Co-B catalyst sample and the nano-aluminum is 1:10-50, and the pH value of the alkaline aqueous solution of the nano-aluminum is 9-11.

8. A catalyst for increasing the amount of hydrogen released by the hydrolysis of nano-aluminum, characterized in that: The catalyst is prepared by the catalyst preparation method for improving the amount of hydrogen released by hydrolysis of nano-aluminum as described in any one of claims 1 to 7.

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