Nickel-aluminum oxide catalyst for ammonia cracking hydrogen production, preparation method and application

Abstract

The application discloses a kind of nickel-aluminum oxide catalyst for ammonia cracking hydrogen production, preparation method and application, belong to catalyst technical field, the present application provides a kind of nickel-aluminum oxide catalyst for ammonia cracking hydrogen production, for solving the technical problems of a large amount of solid waste liquid, poor high-temperature stability in the process of synthesizing nickel-based catalyst in the prior art.The nickel-aluminum oxide catalyst synthesized by the present application is composed of NiO phase and NiAl2O4 phase;The catalyst contains 27% to 59% NiO and 41% to 73% Al2O3 by mass of oxide.The preparation method of the catalyst comprises the following steps: mixing the precursor of nickel and the precursor of aluminum, high-temperature calcination, i.e., the prepared nickel-aluminum oxide catalyst for ammonia cracking hydrogen production.The present application uses solid phase method to synthesize catalyst, process simplification high efficiency, process no waste water and waste gas generation.The presence of part of NiAl2O4 phase helps to improve the stability and high-temperature resistance of the nickel-aluminum oxide catalyst.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically a nickel-aluminum oxide catalyst for ammonia cracking to produce hydrogen, its preparation method, and its application. Background Technology

[0002] Hydrogen energy is a highly efficient and clean secondary energy source with significant application value in fuel cells, energy storage, power peak shaving, and chemical production. With the rapid development of the hydrogen energy industry, developing efficient, safe, and economical hydrogen storage and supply media has become a research hotspot. Ammonia (NH3), as an ideal zero-carbon hydrogen carrier, has significant advantages such as high hydrogen content (17.6% by mass), easy liquefaction and storage (at -33℃ or 1.0MPa at room temperature), and low transportation costs. At the hydrogen storage end, efficient hydrogen storage can be achieved through renewable energy-based water electrolysis to produce hydrogen and nitrogen synthesis of green ammonia; at the hydrogen consumption end, ammonia cracking hydrogen production technology (2NH3→3H2+N) is used. 2） This is considered one of the key technologies for achieving efficient hydrogen energy supply.

[0003] The core of ammonia cracking for hydrogen production lies in the development of high-performance catalysts. Currently, the ammonia cracking catalysts studied mainly include noble metal system catalysts and non-noble metal system catalysts. Noble metal system catalysts (such as Ru, Rh, Pt, etc.) have excellent catalytic activity and low-temperature reaction performance. For example, Ru-based catalysts doped with Cs and supported on carbon (CNT, graphene, etc.) have high efficiency in ammonia cracking for hydrogen production [①NanoEnergy,2025,142:111149;②JournalofScience:Advanced Materials and Devices, 2025, 10(3): 100929]. However, due to the scarcity and high price of noble metals, their large-scale industrial application is greatly limited. In contrast, non-noble metal catalysts have a greater advantage in terms of yield and price. Among non-noble metal catalysts, nickel (Ni)-based catalysts are the most studied, and they have good catalytic activity for ammonia cracking for hydrogen production, such as Ni-CeO built on carbon nanotubes. 2-x The catalyst, through photothermal synergistic catalysis, achieved highly efficient ammonia cracking for hydrogen production, surpassing the performance of many ruthenium-based catalysts [Nature Communications, 2025, 16, 11433]. Recent research progress on interface optimization and novel driving mechanisms for non-precious metal catalysts has not only deepened our understanding of the ammonia cracking hydrogen production reaction mechanism but also provided multiple possible technical routes for achieving efficient, low-cost, and industrially scalable catalytic systems.

[0004] Patent application CN101780413A discloses a nickel-based catalyst for ammonia decomposition, its preparation method, and its application. The method involves thoroughly impregnating γ-alumina in a mixed solution of nickel nitrate and lanthanum nitrate, followed by drying, calcination, and activation treatment to obtain the nickel-based catalyst. However, in the impregnation method for preparing the nickel-based catalyst, nitrates are used as precursors for the active component, which generates a large amount of NO during calcination. x Exhaust gas emissions make it difficult to meet the requirements of green and environmentally friendly catalyst development in today's society. In practical applications, conventionally prepared nickel-based catalysts also require pre-reduction treatment with H2, which increases the complexity of the process and operating costs. In addition, nickel-based catalysts have high reaction temperatures (≥600℃), and under this high temperature, the active Ni center is prone to sintering and growth, resulting in a gradual reduction of active sites and a decrease in catalytic stability, making it difficult to meet the industrial requirements for long-term continuous operation.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a nickel-aluminum oxide catalyst for ammonia cracking to produce hydrogen, its preparation method, and its application, in order to solve the technical problems of nickel-based catalysts used in the prior art for ammonia cracking to produce hydrogen that easily generate polluting waste and have poor high-temperature resistance and stability.

[0007] The objective of this invention can be achieved through the following technical solutions: A nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking is composed of a NiO phase and a NiAl2O4 phase; the catalyst contains 27%-59% NiO and 41%-73% Al2O3 by mass of oxides.

[0008] As another aspect of the present invention, a method for preparing a nickel-aluminum oxide catalyst for ammonia cracking to produce hydrogen includes the following steps: Nickel and aluminum precursors are mixed, ball-milled, and calcined with gradient temperature to produce nickel-aluminum oxide catalysts for ammonia cracking and hydrogen production.

[0009] Furthermore, the ball milling speed is 100-400 r / min and the ball milling time is 3-5 h; the initial temperature of the gradient heating is 20-25℃, the heating rate is 1-10℃ / min until it reaches 1000-1200℃, and then it is calcined for 0-6 h.

[0010] Furthermore, the precursor of nickel is any one of nickel hydroxide, nickel carbonate, nickel acetate, nickel oxide, or nickel oxalate; the precursor of aluminum is any one of boehmite, alumina, and aluminum hydroxide.

[0011] The mass ratio of nickel precursor to aluminum precursor is 10-102.00:20-89.

[0012] As another aspect of the present invention, the application of a nickel-aluminum oxide catalyst for ammonia cracking hydrogen production includes the following steps: A nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking was added to the reactor, and pure ammonia was introduced. The reaction was carried out, and the ammonia conversion rate was calculated.

[0013] Furthermore, the space velocity of the pure ammonia is 10000-35000 mL / g-cat. / h; the reaction temperature is 600-800℃; and the reaction pressure is 0.1-0.6 MPa.

[0014] The present invention has the following beneficial effects: 1. This invention employs a solid-state method, mixing nickel and aluminum precursors and then subjecting them to a high-temperature calcination process. Nickel-aluminum oxide catalysts were synthesized. The solid-phase synthesis of nickel-aluminum catalysts is a simplified and efficient process, generating no waste gas or wastewater. The experimentally prepared nickel-aluminum oxide catalysts also do not require pre-reduction treatment with hydrogen before use, demonstrating the advantage of a simplified process.

[0015] 2. Combined with the appendix Figure 1 and attached Figure 2 As can be seen, in the nickel-aluminum oxide catalyst synthesized in this invention, nickel, aluminum, and oxygen are combined in different crystal structures, including a NiO phase and a face-centered cubic nickel-aluminum spinel NiAl2O4 phase. The presence of a portion of the NiAl2O4 phase helps to improve the stability and high-temperature resistance of the nickel-aluminum oxide catalyst. Experimental tests show that the nickel-aluminum oxide catalyst synthesized in this invention still exhibits high catalytic activity and good stability at high temperature (700℃) and long duration (120h). Attached Figure Description

[0016] Figure 1 The XRD diffraction pattern of the nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking prepared in Example 10 of this invention; Figure 2 The image shows an HRTEM image of the nickel-aluminum oxide catalyst for hydrogen production from ammonia cracking prepared in Example 10 of this invention. Figure 3 The graph shows the change in conversion rate of the catalyst prepared in Example 10 of this invention as a function of reaction time. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] The pseudoboehmite [Al(OOH)・nH2O] used in Examples 1-10 of this invention was purchased from Shandong Shanlv Yifeng Aluminum-based New Materials Co., Ltd., and the n value was 0.714 in all cases. Example 1

[0019] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 50.00 g of nickel hydroxide [Ni(OH)2] and 50.00 g of boehmite [Al(OOH)·nH2O] and add them to a high-speed mixer. Mix at 3000 r / min for 1 h, then ball mill at 200 r / min for 3 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace and calcine at 1000 °C at a heating rate of 1 °C / min under air atmosphere and 25 °C for 5 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking is obtained. Analysis shows that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking is 45.71%, and the mass fraction of Al2O3 is 54.29%. Example 2

[0020] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 50.00 g of nickel carbonate [NiCO3] and 43.50 g of boehmite [Al(OOH)·nH2O] and add them to a high-speed mixer. Mix at 3000 r / min for 1 h, then ball mill at 200 r / min for 5 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace and calcine at 1100 °C at a heating rate of 3 °C / min under air atmosphere and 20 °C for 3 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking is obtained. Analysis shows that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking is 50.82%, and the mass fraction of Al2O3 is 49.18%. Example 3

[0021] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 59.58 g of nickel hydroxide [Ni(OH)2] and 52.00 g of alumina [Al2O3] and add them to a high-speed mixer. Mix at 3000 r / min for 1 h, then ball mill at 230 r / min for 3.5 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace and calcine at 1150 °C at a heating rate of 3 °C / min under air atmosphere and 25 °C for 2 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking is obtained. Analysis shows that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking is 40.31%, and the mass fraction of Al2O3 is 59.69%. Example 4

[0022] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: 102.00 g of nickel acetate [Ni(CH3COO)2·4H2O] and 32.00 g of aluminum hydroxide [Al(OH)3] were accurately weighed and added to a high-speed mixer. The mixture was mixed at 3000 r / min for 1 h, and then ball-milled at 250 r / min for 4 h to obtain a homogeneous mixture. The homogeneous mixture was placed in a muffle furnace and calcined at 1050 °C at a heating rate of 5 °C / min under air atmosphere and 22 °C for 4 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking was obtained. Analysis showed that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking was 58.64%, and the mass fraction of Al2O3 was 41.36%. Example 5

[0023] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: 10.00 g of nickel oxide [NiO] and 89.00 g of boehmite [Al(OOH)·nH2O] were accurately weighed and added to a high-speed mixer. The mixture was mixed at 3000 r / min for 1 h, and then ball-milled at 200 r / min for 3 h to obtain a homogeneous mixture. The homogeneous mixture was placed in a muffle furnace and calcined at 1000 °C at a heating rate of 6 °C / min under air atmosphere and 23 °C for 6 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking was obtained. Analysis showed that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking was 27.0%, and the mass fraction of Al2O3 was 73.0%. Example 6

[0024] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 40.96 g of nickel hydroxide [Ni(OH)2] and 85.00 g of aluminum hydroxide [Al(OH)3], add them to a high-speed mixer, mix at 3000 r / min for 1 h, and then ball mill at 250 r / min for 4 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace, heat it to 1100 °C at a heating rate of 10 °C / min under air atmosphere and 25 °C, and calcine it at this temperature for 3 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking is obtained. Analysis shows that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking is 30.29%, and the mass fraction of Al2O3 is 69.71%. Example 7

[0025] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 55.00 g of nickel acetate [Ni(CH3COO)2·4H2O] and 20.00 g of alumina [Al2O3], add them to a high-speed mixer, mix at 3000 r / min for 1 h, and then ball mill at 200 r / min for 5 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace, heat it to 1100 °C at a heating rate of 8 °C / min under air atmosphere and calcine it at this temperature for 5 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking is obtained. Analysis shows that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking is 44.43%, and the mass fraction of Al2O3 is 55.57%. Example 8

[0026] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 55.00 g of nickel oxalate [NiC2O4·2H2O] and 39.30 g of alumina [Al2O3], add them to a high-speed mixer, mix at 3000 r / min for 1 h, and then ball mill at 280 r / min for 3.2 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace, heat it to 1200 °C at a heating rate of 10 °C / min under air atmosphere and at 25 °C, then directly cool it down and allow it to cool naturally to obtain a nickel-aluminum oxide catalyst for ammonia cracking. Analysis showed that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking was 36.39%, and the mass fraction of Al2O3 was 63.61%. Example 9

[0027] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 54.00 g of nickel oxide [NiO] and 70.38 g of aluminum hydroxide [Al(OH)3], add them to a high-speed mixer, mix at 3000 r / min for 1 h, and then ball mill at 260 r / min for 4 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace, heat it to 1000 °C at a heating rate of 5 °C / min under air atmosphere and calcine it at this temperature for 4 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking is obtained. Analysis shows that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking is 54.00%, and the mass fraction of Al2O3 is 46.00%. Example 10

[0028] This embodiment provides a method for preparing a nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking, including the following steps: Accurately weigh 40.00 g of nickel hydroxide [Ni(OH)2] and 45.98 g of boehmite [Al(OOH)·nH2O], add them to a high-speed mixer, mix at 3000 r / min for 1 h, and then ball mill at 300 r / min for 3 h to obtain a homogeneous mixture. Place the homogeneous mixture in a muffle furnace, heat it to 1100 °C at a heating rate of 3 °C / min under air atmosphere and 23 °C, and calcine it at this temperature for 3 h. After natural cooling, a nickel-aluminum oxide catalyst for ammonia cracking is obtained. Analysis shows that the mass fraction of NiO in the above-mentioned nickel-aluminum oxide catalyst for ammonia cracking is 42.00%, and the mass fraction of Al2O3 is 58.00%. Example 11

[0029] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for hydrogen production from ammonia cracking prepared in Example 1 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity was 10000 mL / g-cat. / h, the reaction temperature was 600 °C, and the reaction pressure was 0.1 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 73.5%. Example 12

[0030] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for ammonia cracking to hydrogen prepared in Example 2 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity (GHSV) was 35000 mL / g-cat. / h, the reaction temperature was 800 °C, and the reaction pressure was 0.6 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 85.1%. Example 13

[0031] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The performance of the nickel-aluminum oxide catalyst for hydrogen production from ammonia cracking prepared in Example 3 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity (GHSV) was 28000 mL / g-cat. / h, the reaction temperature was 760 °C, and the reaction pressure was 0.3 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 82.4%. Example 14

[0032] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for ammonia cracking to hydrogen prepared in Example 4 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity was 18000 mL / g-cat. / h, the reaction temperature was 700 °C, and the reaction pressure was 0.1 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 79.3%. Example 15

[0033] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for hydrogen production from ammonia cracking prepared in Example 5 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity was 18000 mL / g-cat. / h, the reaction temperature was 750 °C, and the reaction pressure was 0.2 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 80.2%. Example 16

[0034] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for ammonia cracking to hydrogen prepared in Example 6 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity was 30,000 mL / g-cat. / h, the reaction temperature was 780 °C, and the reaction pressure was 0.5 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 88.9%. Example 17

[0035] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for ammonia cracking to hydrogen prepared in Example 7 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity was 25000 mL / g-cat. / h, the reaction temperature was 740 °C, and the reaction pressure was 0.1 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 82.6%. Example 18

[0036] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for ammonia cracking to hydrogen prepared in Example 8 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity was 10000 mL / g-cat. / h, the reaction temperature was 800 °C, and the reaction pressure was 0.6 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 95.0%. Example 19

[0037] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The reaction performance of the nickel-aluminum oxide catalyst for ammonia cracking to hydrogen prepared in Example 9 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity was 30,000 mL / g-cat. / h, the reaction temperature was 800 °C, and the reaction pressure was 0.4 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 89.3%. Example 20

[0038] This embodiment provides an application of a nickel-aluminum oxide catalyst for hydrogen production via ammonia cracking, including the following steps: The performance of the nickel-aluminum oxide catalyst for hydrogen production from ammonia cracking prepared in Example 10 was evaluated using a fixed-bed reactor. The reactant was pure ammonia, the gas hourly space velocity (GHSV) was 21000 mL / g-cat. / h, the reaction temperature was 700 °C, and the reaction pressure was 0.1 MPa. Online analysis was performed using a gas chromatograph equipped with a thermal conductivity detector (TCD), and the ammonia conversion rate was calculated to be 75.1%.

[0039] Performance testing: 1. The nickel-aluminum oxide catalyst prepared in Example 10 was characterized by X-ray diffraction (XRD), and the results are shown in the appendix. Figure 1 .

[0040] 2. The nickel-aluminum oxide catalyst prepared in Example 10 was characterized by transmission electron microscopy (TEM), and the results are shown in the appendix. Figure 2 .

[0041] 3. A long-term ammonia cracking hydrogen production test was conducted on the nickel-aluminum oxide catalyst prepared in Example 10. Based on the experiment in Example 20, a continuous operation experiment of 120 h was carried out on the nickel-aluminum oxide catalyst. The corresponding ammonia conversion results are shown in the appendix. Figure 3 .

[0042] Data Analysis: Based on Appendix Figure 1 The XRD pattern shows that the nickel-aluminum oxide catalyst prepared in this invention exhibits NiAl2O4 diffraction peaks; NiAl2O4 itself has a face-centered cubic nickel-aluminum spinel structure, which helps to improve the high-temperature resistance and stability of the synthesized catalyst. (See attached diagram.) Figure 2 The HRTEM image of the nickel-aluminum oxide catalyst prepared in Example 10 shows a lattice spacing of 0.201 mm, which corresponds to the lattice spacing of the NiAl2O4 (400) crystal plane, indicating that the prepared nickel-aluminum oxide catalyst contains the NiAl2O4 phase.

[0043] According to the appendix Figure 3 It can be seen that the nickel-aluminum oxide catalyst prepared by this invention still has good high temperature resistance and stability in the stability experiment of continuous operation, and always exhibits high catalytic activity and good catalytic stability.

[0044] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0045] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A nickel-aluminum oxide catalyst for hydrogen production from ammonia cracking, characterized in that, It is composed of NiO phase and NiAl2O4 phase; the catalyst contains 27%-59% NiO and 41%-73% Al2O3 by mass of oxides.

2. A method for preparing a nickel-aluminum oxide catalyst for ammonia cracking to hydrogen production according to claim 1, characterized in that, Includes the following steps: Nickel and aluminum precursors are mixed, ball-milled, and calcined with gradient temperature to produce nickel-aluminum oxide catalysts for ammonia cracking and hydrogen production.

3. The method for preparing a nickel-aluminum oxide catalyst for ammonia cracking to hydrogen production according to claim 2, characterized in that, The ball milling speed is 100-400 r / min and the ball milling time is 3-5 h; the initial temperature of the gradient heating is 20-25℃, the heating rate is 1-10℃ / min until it reaches 1000-1200℃, and then it is calcined for 0-6 h.

4. The method for preparing a nickel-aluminum oxide catalyst for ammonia cracking to hydrogen production according to claim 2, characterized in that, The precursor of nickel is any one of nickel hydroxide, nickel carbonate, nickel acetate, nickel oxide, or nickel oxalate; the precursor of aluminum is any one of boehmite, alumina, and aluminum hydroxide.

5. The method for preparing a nickel-aluminum oxide catalyst for ammonia cracking to hydrogen production according to claim 2, characterized in that, The mass ratio of nickel precursor to aluminum precursor is 10-102.00:20-89.

6. The application of a nickel-aluminum oxide catalyst for ammonia cracking to hydrogen production as described in claim 1 in ammonia cracking to hydrogen production, characterized in that, Includes the following steps: A nickel-aluminum oxide catalyst for hydrogen production by ammonia cracking was added to the reactor, pure ammonia was introduced, the reaction was carried out, and the ammonia conversion rate was calculated.

7. The application of the nickel-aluminum oxide catalyst for ammonia cracking hydrogen production according to claim 6 in ammonia cracking hydrogen production, characterized in that, The space velocity of pure ammonia is 10000-35000 mL / g-cat. / h; the reaction temperature is 600-800℃; and the reaction pressure is 0.1-0.6 MPa.

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