Supported nickel-based catalysts, methods of making and using the same, and methods of hydrogen production by ammonia decomposition

Abstract

The present application relates to the field of ammonia decomposition catalyst preparation, discloses a supported nickel-based catalyst, a preparation method and application thereof, and a method for hydrogen production by ammonia decomposition.A supported nickel-based catalyst, the catalyst containing a barium titanate carrier and a nickel element supported on the barium titanate carrier; the content of nickel is 2-15 wt% based on the total weight of the catalyst in terms of nickel oxide; wherein the average particle size of the catalyst is 1-10 microns.The catalyst has high activity, and when applied to hydrogen production by ammonia decomposition, it has high ammonia decomposition conversion rate at low temperature and large space velocity.

Description

Technical Field

[0001] This invention relates to the field of ammonia decomposition catalyst preparation, specifically to a supported nickel-based catalyst, its preparation method and application, and a method for producing hydrogen from ammonia decomposition. Background Technology

[0002] Currently, hydrogen is almost entirely derived from catalytic steam reforming of fossil fuels, which is also the most commercially mature hydrogen production technology. However, the hydrogen produced by catalytic reforming contains impurities such as carbon monoxide and carbon dioxide, making it unsuitable for direct use as fuel in fuel cells. Therefore, using ammonia, a hydrogen-rich carrier, as a feedstock for carbon-free hydrogen production is a highly efficient, clean, and safe hydrogen production technology. To achieve safe and green hydrogen production, developing catalysts capable of efficiently catalyzing ammonia decomposition is particularly important. Currently, ammonia decomposition catalysts are divided into noble metal catalysts with ruthenium and platinum as active components and non-noble metal catalysts with iron and nickel as active components.

[0003] The high cost and low reserves of precious metals limit their application in large-scale industrial applications. Therefore, the core of developing efficient and inexpensive ammonia decomposition hydrogen production technology lies in low-cost, highly active, and highly stable non-precious metal catalysts. However, non-precious metal catalysts require relatively harsh reaction conditions, and the operating temperature is generally higher than 800℃. Extensive research has been conducted on low-temperature non-precious metal ammonia decomposition catalysts. For example, CN1506299A discloses a nickel-based ammonia decomposition hydrogen-nitrogen mixed gas catalyst, whose main active component is Ni; the support is SiO2 or Al2O3; the promoter is one or more of IA, IIA, IIIB, VIII, or rare earth elements; the nickel weight percentage is 1-40%; and the promoter component weight percentage is 0.1-20%. Catalysts prepared using SiO2 or Al2O3 as supports, although improved by introducing promoters, can achieve ammonia decomposition at 650℃, a significant reduction compared to the 800℃ reaction temperature of industrial catalysts. However, due to the poor dispersion of the promoters on the support surface, they easily form large particles, resulting in poor ammonia decomposition activity at low temperatures. CN115646500A discloses an ammonia decomposition hydrogen production catalyst, comprising an active metal component, an alkaline earth metal component, a lanthanide metal component, and promoters. This patent application uses alkaline earth metal doping to improve the dispersion of the nickel-based catalyst and reduce particle size. Compared to the unmodified catalyst, the activity of this patented catalyst is improved to some extent. Although the reaction temperature is reduced to 550℃, the reaction space velocity is only 6000 mL / (g·h), indicating room for further improvement. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem that the activity and stability of existing ammonia decomposition catalysts at low temperatures need further improvement, and to provide a supported nickel-based catalyst, its preparation method and application, as well as a method for ammonia decomposition to produce hydrogen. This catalyst exhibits high activity and, when applied to ammonia decomposition to produce hydrogen, demonstrates a high ammonia decomposition conversion rate at low temperatures and high space velocities.

[0005] To achieve the above objectives, the present invention provides a supported nickel-based catalyst, wherein the catalyst contains a barium titanate support and nickel element supported on the barium titanate support, and the nickel content is 2-15% by weight, based on the total weight of the catalyst and calculated as nickel oxide.

[0006] The catalyst has an average particle size of 1-10 micrometers.

[0007] A second aspect of this invention provides a method for preparing a supported nickel-based catalyst, the method comprising the following steps:

[0008] S1. Grind the titanium-containing compound and the barium-containing compound to obtain powder with an average particle size of 0.1-7 micrometers;

[0009] S2. The powder obtained in S1 is dried and first calcined to obtain barium titanate support;

[0010] S3. Nickel elements are loaded onto a barium titanate support using an impregnation method.

[0011] The third aspect of this invention provides the application of the supported nickel-based catalyst described in the first aspect or the supported nickel-based catalyst prepared by the preparation method described in the second aspect in the ammonia decomposition for hydrogen production.

[0012] A fourth aspect of the present invention provides a method for producing hydrogen by ammonia decomposition, the method comprising: contacting ammonia with a catalyst under ammonia decomposition conditions;

[0013] The catalyst is either the catalyst described in the first aspect or a supported nickel-based catalyst prepared by the preparation method described in the second aspect.

[0014] The beneficial effects of the present invention through the above technical solution include:

[0015] The catalyst provided by this invention utilizes the synergistic effect of barium titanate and nickel active components, thereby improving the catalyst's activity at low temperatures. Simultaneously, the nickel content is in the range of 2-15% by weight, which enhances the interaction between the nickel active component and the support, effectively weakening the interaction between the active component and ammonia decomposition products, thus promoting the desorption of nitrogen and hydrogen. Preferably, the catalyst of this invention does not contain precious metals such as Ru, resulting in low cost.

[0016] The preparation process of the supported nickel-based catalyst described in this invention is simple, reproducible, and easy to scale up for production. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of the present invention provides a supported nickel-based catalyst, the catalyst containing a barium titanate support and nickel element supported on the barium titanate support; based on the total weight of the catalyst, the nickel content is 2-15% by weight, calculated as nickel oxide;

[0019] The catalyst has an average particle size of 1-10 micrometers.

[0020] The inventors of this invention have discovered that using barium titanate as a support can effectively regulate the acidity and alkalinity of the catalyst surface, adjust the electron transfer capacity between the active component in the catalyst and the support, regulate the adsorption and desorption intensity of NH3 on the catalyst surface, promote the transfer of NH3 between the active site and the support, and improve catalytic activity.

[0021] In this invention, based on the total weight of the catalyst, the nickel content, calculated as nickel oxide, is 2-15% by weight, preferably 5-15% by weight, for example 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight, 15% by weight, and any value within any two of these ranges. This preferred embodiment enhances the interaction between the nickel active component and the support, effectively weakens the interaction between the active component and ammonia decomposition products, thereby promoting the desorption of nitrogen and hydrogen.

[0022] The total content of all components in the catalyst described in this invention is 100%.

[0023] The content of the active component in the catalyst of the present invention was determined by XRF characterization.

[0024] According to the present invention, preferably, the average particle size of the catalyst is 1-10 micrometers, more preferably 2-8 micrometers, for example, it can be 1 micrometer, 2 micrometers, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, and any value within any two of these ranges. This preferred embodiment is beneficial for promoting the uniform distribution of active components on the catalyst surface, thereby improving the catalyst activity.

[0025] The average particle size of the catalyst described in this invention was measured using a particle size analyzer.

[0026] Preferably, the catalyst does not contain precious metals. This preferred embodiment can save costs.

[0027] A second aspect of the present invention provides a method for preparing a catalyst, the method comprising the following steps:

[0028] S1. Grind the titanium-containing compound and the barium-containing compound to obtain powder with an average particle size of 0.1-7 micrometers;

[0029] S2. The powder obtained in S1 is dried and first calcined to obtain barium titanate support;

[0030] S3. Nickel elements are loaded onto a barium titanate support using an impregnation method.

[0031] The preparation method provided by the present invention first uses a solid-phase synthesis method to prepare a barium titanate support, and then uses an impregnation method to load the nickel active component onto the barium titanate support. A catalyst with high activity and good stability can be obtained by using a simple method.

[0032] According to the present invention, preferably, in S1, the molar ratio of the barium-containing compound to the titanium-containing compound is 1:2-8, more preferably 1:2-6.

[0033] The present invention has a wide range of choices for the types of titanium-containing compounds. Preferably, the titanium-containing compounds are titanium dioxide and / or metatitanic acid.

[0034] The present invention has a wide range of choices for the types of barium-containing compounds. Preferably, the barium-containing compounds are barium carbonate and / or barium hydroxide.

[0035] According to the present invention, preferably, the average particle size of the powder obtained in S1 is 1-6 micrometers, for example, it can be 1 micrometer, 2 micrometers, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, and any value within the range formed by any two of these values. This preferred embodiment is advantageous for obtaining a catalyst with the average particle size described in the first aspect.

[0036] The present invention does not particularly limit the grinding conditions described in S1, as long as the powder with the above-mentioned average particle size is obtained. Preferably, the grinding conditions described in S1 include: a rotation speed of 150-600 rpm, more preferably 200-400 rpm; and a grinding time of 3-60 min, more preferably 5-30 min.

[0037] This invention does not impose any particular limitation on the apparatus used for grinding; various apparatuses conventionally used in grinding in this field can be employed. A ball mill is preferred in this invention.

[0038] The present invention does not particularly limit the specific drying conditions, and can refer to conventional methods in the art. Preferably, in S2, the drying conditions include: a temperature of 70-120°C and a time of 8-48 hours.

[0039] According to the present invention, preferably, in S2, the conditions for the first calcination include: a temperature of 600-900°C and a time of 2-6 hours. This preferred embodiment helps to promote the subsequent interaction between the active component and the support.

[0040] According to the present invention, preferably, the impregnation method in S3 includes:

[0041] (1) Add an aqueous solution containing nickel salt to a barium titanate support to obtain a catalyst precursor;

[0042] (2) The catalyst precursor is aged, then dried and calcined.

[0043] This preferred embodiment facilitates the diffusion and secondary crystallization of nickel ions on the surface of the barium titanate support, further enhancing the catalyst activity.

[0044] Preferably, step (1) includes adding an aqueous solution containing nickel salt to a barium titanate support by dropping it to obtain a catalyst precursor.

[0045] According to one specific embodiment of the present invention, an aqueous solution containing nickel salt is added dropwise to a barium titanate support while stirring, to obtain a catalyst precursor.

[0046] The present invention does not impose a particular limitation on the stirring rate, which can be appropriately selected according to the specific circumstances, with the aim of achieving uniform mixing.

[0047] According to the present invention, preferably, the amount of nickel salt used is such that, based on the total weight of the catalyst, the nickel content in the prepared catalyst is 2-15% by weight, preferably 5-15% by weight, calculated as nickel oxide.

[0048] The present invention does not impose any particular limitation on the type of nickel salt, and any conventional choice in the art may be made. Preferably, the nickel salt is a nickel nitrate and / or hydrochloride.

[0049] Preferably, the concentration of the nickel-containing salt aqueous solution is 0.3-1.5 mol / L.

[0050] According to the present invention, preferably, the aging conditions in step (2) include: a temperature of 40-60°C and a time of 1-3 hours.

[0051] The present invention does not have any particular limitation on the drying in step (2), and can be carried out with reference to conventional methods in the art. The present invention will not describe it in detail here.

[0052] According to the present invention, preferably, the conditions for the second calcination in step (2) include: a temperature of 550-780°C and a time of 2-5 hours. This preferred embodiment is beneficial for the uniform distribution of nickel oxide and for improving the catalytic performance of the catalyst.

[0053] According to the present invention, preferably, the method further includes: reducing the product of the second calcination to obtain the catalyst.

[0054] The present invention does not particularly limit the reduction conditions, and can be carried out with reference to conventional methods in the art. Preferably, the reduction conditions include: a temperature of 600-800℃ and a time of 1-3 hours.

[0055] According to the present invention, preferably, the reduction is carried out in a reducing gas, which includes hydrogen and optionally an inert gas; wherein the volume content of hydrogen in the reducing gas is 10-100%.

[0056] In this invention, unless otherwise specified, "optionally" means containing or not containing, adding or not adding, or using or not using. Specifically, in the reduction step of this invention, an inert gas may or may not be added.

[0057] According to the present invention, preferably, the inert gas is selected from at least one of nitrogen, helium, argon and neon.

[0058] In this invention, the terms "first" and "second" do not limit the substances and operations, but are only used to distinguish the substances introduced in different steps and the operations performed in different stages.

[0059] The third aspect of this invention provides the application of the supported nickel-based catalyst described in the first aspect or the supported nickel-based catalyst prepared by the preparation method described in the second aspect in the ammonia decomposition for hydrogen production.

[0060] A fourth aspect of the present invention provides a method for producing hydrogen by ammonia decomposition, the method comprising: contacting ammonia with a catalyst under ammonia decomposition conditions;

[0061] The catalyst is either the catalyst described in the first aspect or a supported nickel-based catalyst prepared by the preparation method described in the second aspect.

[0062] In existing technologies, the temperature for ammonia decomposition reactions using catalysts without precious metals is generally above 550°C. However, the catalyst described in this invention maintains high ammonia decomposition activity even at low temperatures, with ammonia decomposition temperatures as low as 550°C. Furthermore, the ammonia decomposition reaction described in this invention can proceed at relatively high space velocities, and it maintains high ammonia decomposition activity even after long-term evaluation experiments, indicating that the catalyst described in this invention has good stability.

[0063] According to the present invention, preferably, the conditions for the ammonia decomposition include: a temperature of 550-650°C and a volume hourly space velocity of 5000-20000 mL / (g·h).

[0064] The present invention will be described in detail below through embodiments.

[0065] In the following examples, the ammonia decomposition conversion rate formula is as follows:

[0066] Ammonia decomposition conversion rate = (raw material ammonia content - product ammonia content) / raw material ammonia content × 100%.

[0067] Example 1

[0068] 13.42 g of titanium dioxide and 16.58 g of barium carbonate were weighed and mixed in a ball mill, and ground at 200 rpm for 15 min to obtain powder with an average particle size of 6.9 μm. The powder was dried at 120 °C for 2 h and then calcined at 800 °C for 4 h to obtain barium titanate support.

[0069] 1.74 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 9 g of barium titanate powder while stirring to obtain a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 120 °C for 9 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixture of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain a supported nickel-based catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0070] Example 2

[0071] 18.54 g of titanium dioxide and 11.46 g of barium carbonate were weighed and mixed in a ball mill, and ground at 400 rpm for 20 min to obtain powder with an average particle size of 5 micrometers. The powder was dried at 120℃ for 2 h and then calcined at 800℃ for 4 h to obtain barium titanate support.

[0072] 1.74 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 9 g of barium titanate powder while stirring to obtain a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 120 °C for 9 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixed gas of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain 10 g of supported nickel-based catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0073] Example 3

[0074] 21.25g of titanium dioxide and 7.6g of barium hydroxide were weighed and mixed in a ball mill, and ground at 400 rpm for 20 min to obtain powder with an average particle size of 4.8 μm. The powder was dried at 120℃ for 2 h and then calcined at 800℃ for 4 h to obtain barium titanate support.

[0075] 1.74 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 9 g of barium titanate powder while stirring to obtain a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 120 °C for 9 h, and calcined at 600 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixed gas of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain 10 g of supported nickel-based catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0076] Example 4

[0077] 18.54 g of titanium dioxide and 11.46 g of barium carbonate were weighed and mixed in a ball mill, and ground at 400 rpm for 30 min to obtain powder with an average particle size of 4.1 μm. The powder was dried at 100 °C for 2 h and then calcined at 800 °C for 4 h to obtain barium titanate support.

[0078] 1.74 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 9 g of barium titanate powder while stirring to obtain a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 120 °C for 9 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixed gas of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain 10 g of supported nickel-based catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0079] Example 5

[0080] 18.54 g of titanium dioxide and 11.46 g of barium carbonate were weighed and mixed in a ball mill, and ground at 400 rpm for 5 min to obtain powder with an average particle size of 6.8 μm. The powder was dried at 120 °C for 2 h and then calcined at 800 °C for 4 h to obtain barium titanate support.

[0081] 1.74 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 9 g of magnesium titanate powder while stirring to obtain a catalyst precursor. The precursor was aged at 45 °C for 3 h, dried at 120 °C for 12 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixed gas of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain 10 g of supported nickel-based catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0082] Example 6

[0083] 18.54 g of titanium dioxide and 11.46 g of barium carbonate were weighed and mixed in a ball mill, and ground at 400 rpm for 20 min to obtain powder with an average particle size of 5 micrometers. The powder was dried at 120℃ for 2 h and then calcined at 700℃ for 5 h to obtain barium titanate support.

[0084] 0.35 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 9.8 g of barium titanate powder while stirring to obtain a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 110 °C for 9 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixed gas of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain 10 g of supported nickel-based catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0085] Example 7

[0086] 18.54 g of titanium dioxide and 11.46 g of barium carbonate were weighed and mixed in a ball mill, and ground at 400 rpm for 20 min to obtain powder with an average particle size of 5 micrometers. The powder was dried at 120℃ for 2 h and then calcined at 800℃ for 4 h to obtain barium titanate support.

[0087] 2.6 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 8.5 g of barium titanate powder while stirring to obtain a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 120 °C for 9 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixed gas of hydrogen and nitrogen (15% hydrogen integral) at 750 °C for 2 h to obtain 10 g of supported nickel-based catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0088] Example 8

[0089] The procedure was carried out according to Example 1, except that barium titanate was prepared by precipitation: Tetrabutyl titanate was used as the titanium source. 57.18g of tetrabutyl titanate was dissolved in 200ml of anhydrous ethanol, and the pH was adjusted to about 1.4 with hydrochloric acid to obtain a titanium source solution. 21.95g of barium nitrate was dissolved in 100mL of deionized water to obtain a barium source solution. The prepared titanium source solution was added dropwise to the barium source solution and reacted at 30°C for 2h. The resulting white precipitate was washed and filtered, then dried at 120°C for 9h. The dried solid was then calcined in a muffle furnace at 700°C for 4h to obtain solid barium titanate.

[0090] 9g of barium titanate was used to obtain 10g of catalyst.

[0091] Comparative Example 1

[0092] 2.6 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 8.5 g of titanium dioxide powder while stirring, yielding a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 120 °C for 9 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixture of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain 10 g of catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0093] Comparative Example 2

[0094] 1.74 g of nickel chloride was dissolved in deionized water to prepare a 0.5 mol / L nickel chloride solution. This solution was then added dropwise to 9 g of titanium dioxide powder while stirring to obtain a catalyst precursor. The precursor was aged at 50 °C for 2 h, dried at 120 °C for 9 h, and calcined at 550 °C for 2 h to obtain the calcined product. The calcined product was reduced with a mixture of hydrogen and nitrogen (15% hydrogen integral) at 700 °C for 3 h to obtain 10 g of catalyst. The catalyst composition and characteristic parameters are shown in Table 1.

[0095] Comparative Example 3

[0096] The procedure was carried out according to Example 1, except that instead of adding barium carbonate, an equimolar amount of magnesium carbonate was added. 10 g of catalyst was obtained. The catalyst composition and characteristic parameters are shown in Table 1.

[0097] Comparative Example 4

[0098] The method of Example 1 was followed, except that 13.42 g of titanium dioxide and 16.58 g of barium carbonate were weighed and mixed in a ball mill, and ground at 50 rpm for 5 min to obtain powder with an average particle size of 22.3 μm. 10 g of supported nickel-based catalyst was obtained. The catalyst composition and characteristic parameters are shown in Table 1.

[0099] Comparative Example 5

[0100] The method of Example 1 was followed, except that the amount of nickel chloride was adjusted so that, based on the total weight of the catalyst, the nickel content, calculated as nickel oxide, was 20% by weight. The catalyst composition and characteristic parameters are shown in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] Note: The remainder of the catalyst is barium titanate support.

[0105] Test Example 1

[0106] The activity of the catalyst was evaluated using ammonia nitrogen gas with an ammonia concentration of 15% by volume at different temperatures. 1g of the catalyst prepared in the examples and comparative examples with 4g of 40-60 mesh quartz sand was mixed and packed, and the volume hourly space velocity was 15000mL / (g·h). The results after 6h of reaction are shown in Table 2.

[0107] Table 2

[0108]

[0109] As can be seen from the results in Table 2, under the same reaction conditions, the catalyst described in this invention has a significantly higher ammonia decomposition conversion rate when applied to the ammonia decomposition hydrogen production reaction.

[0110] Meanwhile, compared with the comparative example, the catalyst provided by the embodiments of the present invention has a significantly higher ammonia decomposition conversion rate at 550°C, indicating that the catalyst of the present invention has high ammonia decomposition activity at low temperatures.

[0111] Compared to the comparative example, the catalyst provided in this embodiment of the invention exhibits a significantly higher ammonia decomposition conversion rate at a higher space velocity, indicating that the catalyst described in this invention has better stability.

[0112] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A supported nickel-based catalyst, characterized in that, The catalyst contains a barium titanate support and nickel supported on the barium titanate support; based on the total weight of the catalyst, the nickel content, calculated as nickel oxide, is 2-15% by weight. The catalyst has an average particle size of 1-10 micrometers. The preparation method of the supported nickel-based catalyst includes the following steps: S1. Grind the titanium-containing compound and the barium-containing compound to obtain powder with an average particle size of 0.1-7 micrometers; S2. The powder obtained in S1 is dried and subjected to a first calcination to obtain a barium titanate support; in S2, the conditions for the first calcination include: a temperature of 600-800℃ and a time of 2-6 hours. S3. Nickel elements are loaded onto a barium titanate support using an impregnation method, followed by a second calcination and reduction.

2. The catalyst according to claim 1, wherein, Based on the total weight of the catalyst, the nickel content is 5-15% by weight, calculated as nickel oxide.

3. The catalyst according to claim 1, wherein, The catalyst has an average particle size of 2-8 micrometers.

4. A method for preparing a supported nickel-based catalyst, the method comprising the following steps: S1. Grind the titanium-containing compound and the barium-containing compound to obtain powder with an average particle size of 0.1-7 micrometers; S2. The powder obtained in S1 is dried and first calcined to obtain barium titanate support; In S2, the conditions for the first calcination include: a temperature of 600-800℃ and a time of 2-6 hours; S3. Nickel elements are loaded onto a barium titanate support using an impregnation method, followed by a second calcination and reduction. In the catalyst, based on the total weight of the catalyst and calculated as nickel oxide, the nickel content is 2-15% by weight. The catalyst has an average particle size of 1-10 micrometers.

5. The method according to claim 4, wherein, In S1, the molar ratio of the barium-containing compound to the titanium-containing compound is 1:2-8.

6. The method according to claim 5, wherein, In S1, the molar ratio of the barium-containing compound to the titanium-containing compound is 1:2-6.

7. The method according to claim 4, wherein, The titanium-containing compound is titanium dioxide and / or metatitanic acid; The barium-containing compound is barium carbonate and / or barium hydroxide.

8. The method according to claim 4, wherein, The average particle size of the powder obtained by S1 is 1-6 micrometers; The grinding conditions described in S1 include: a rotation speed of 150-600 rpm; The grinding time is 3-60 minutes.

9. The method according to claim 4, wherein, In S2, the drying conditions include a temperature of 70-120°C and a time of 8-48 hours.

10. The method according to any one of claims 4-9, wherein, The impregnation method described in S3 includes: (1) An aqueous solution containing nickel salt was added to a barium titanate support to obtain a catalyst precursor; (2) The catalyst precursor is aged, then dried and calcined.

11. The method according to claim 10, wherein, The amount of nickel salt used results in a catalyst containing 2-15% nickel by weight, based on the total weight of the catalyst and calculated as nickel oxide.

12. The method according to claim 11, wherein, The amount of nickel salt used results in a catalyst containing 5-15% nickel by weight, based on the total weight of the catalyst and calculated as nickel oxide.

13. The method according to claim 10, wherein, The aging conditions described in step (2) include: a temperature of 40-60℃ and a time of 1-3 hours; Step (2) The conditions for the second roasting include: a temperature of 550-780℃ and a time of 2-5 hours.

14. The method of claim 10, wherein, The reduction conditions include: a temperature of 600-800℃ and a time of 1-3 hours; The reduction is carried out in a reducing gas, which includes hydrogen and optionally nitrogen and optionally an inert gas; in the reducing gas, the volume content of hydrogen is 10-100%.

15. The method according to claim 14, wherein, The inert gas is selected from at least one of helium, argon, and neon.

16. The application of a catalyst according to any one of claims 1-3 or a catalyst prepared by any one of claims 4-15 in the ammonia decomposition for hydrogen production.

17. A method for producing hydrogen by decomposition of ammonia, the method comprising: Under conditions of ammonia decomposition, ammonia is brought into contact with a catalyst; The catalyst is the catalyst according to any one of claims 1-3 or the catalyst prepared by the preparation method according to any one of claims 4-15.

18. The method according to claim 17, wherein, The conditions for ammonia decomposition include: a temperature of 550-650℃ and a volume hourly space velocity of 5000-20000 mL / (g·h).

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