Catalyst for hydrogen production through ammonia decomposition as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for hydrogen production through ammonia decomposition as well as a preparation method and application of the catalyst. A catalyst for hydrogen production through ammonia decomposition comprises an attapulgite carrier and an active component loaded on the attapulgite carrier, and the active component is ruthenium and / or nickel. The preparation method has the advantages that the adopted carrier material attapulgite is easy to obtain and low in cost; the natural attapulgite is adopted as a carrier material and is loaded with the active components ruthenium and nickel, the obtained catalyst has excellent catalytic performance in hydrogen production through ammonia decomposition, 100% conversion of ammonia can be achieved only by loading a small amount of active metal components on the attapulgite, and the cost of hydrogen production through ammonia decomposition is greatly reduced; the preparation process of the catalyst is simple, complex chemical reaction and modification treatment are not needed, only the attapulgite and the active component precursor need to be directly impregnated, the preparation process is simplified, and the catalyst is suitable for large-area production.

Description

Technical Field

[0001] The present disclosure relates to the technical field of hydrogen production, and particularly to a catalyst for ammonia decomposition to produce hydrogen, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen is a clean energy source, and its oxidation product is only water, making it an ideal fuel for proton exchange membrane fuel cells. However, the storage and transportation of hydrogen are one of the reasons hindering the large-scale application of hydrogen. Compared with hydrogen, ammonia has the advantages of being easily liquefied (liquefiable under the conditions of 10 atm at room temperature or -33 °C at atmospheric pressure), having a narrow explosion limit (16 - 25%), and mature transportation technology when used as a fuel for proton ceramic fuel cells. In addition, no CO x and NO x is produced during the decomposition of ammonia, only hydrogen and nitrogen are generated, and nitrogen will not harm the battery. However, when ammonia is directly used as a fuel for proton exchange membrane fuel cells, the performance of the battery drops sharply, and the actual conversion rate of ammonia is very low at the operating temperature of the battery. To solve this problem, catalysts are currently widely used to decompose ammonia as much as possible to reduce the negative impact of ammonia on the battery.

[0003] Among single metals, ruthenium (Ru) exhibits the most excellent catalytic activity for ammonia decomposition to produce hydrogen. In practical applications, the active metal needs to be loaded on a support, and the support material is required to have good thermal stability, chemical stability, and a high specific surface area. So far, the synthetic materials that meet these basic conditions are mainly divided into oxides and carbon-based materials. The preparation methods of oxide supports mainly include solid-phase method, sol-gel method, citric acid complex method, co-precipitation method, and pyrolysis method, etc. Among carbon-based materials, the most commonly used carbon nanotubes are generally prepared by the more complex and costly chemical vapor deposition method, and the market price of carbon nanotubes ranges from several hundred to over a thousand yuan per milligram.

[0004] In summary, although the ruthenium nanoparticle catalysts supported by the previous support materials have shown excellent performance, these supports still face the problem of high cost. Therefore, the problems of difficult availability and high price of the support materials need to be solved urgently.

[0005] References

[0006] [1] S. Ren, F. Huang, J. Zheng, S. J. Chen, H. Zhang, Ruthenium supported on nitrogen-doped ordered mesoporous carbon as highly active catalyst for NH3 decomposition to H2, International Journal of Hydrogen Energy, 42(2017)5105-5113.

[0008] [2] Z. Q. Wang, Y. M. Qu, X. L. Shen, Z. F. Cai, Ruthenium catalyst supported on Ba modified ZrO2 for ammonia decomposition to COx-free hydrogen, International Journal of Hydrogen Energy, 44(2019)7300-7307.

[0009] [3] J. W. Zhao, S. Xu, H. J. Wu, Z. X. You, L. D. Deng, X. H. Qiu, Metal-support interactions on

[0010] Ru / CaAlOx catalysts derived from structural reconstruction of Ca-Al layered double hydroxides for

[0011] ammonia decomposition, Chemical Communications, 55(2019)14410-14413.

[0012] [4] C. Chen, Y. W. Chen, A. M. Ali, W. J. Luo, J. Wen, L. H. Zhang, H. Zhang, Bimetallic Ru-Fe

[0013] Nanoparticles Supported on Carbon Nanotubes for Ammonia Decompositionand Synthesis,Chemical Engineering&Technology,43(2020)719-730.

[0014] [5]Y.Im,H.Muroyama,T.Matsui,K.Eguchi,Investigation on catalyticperformance and desorption behaviors of ruthenium catalysts supported onrare-earth oxides for NH3 decomposition,International Journal of HydrogenEnergy,47(2022)32543-32551.

[0015] [6]Z.G.Hu,J.Mahin,S.Datta,T.E.Bell,L.Torrente-Murciano,Ru-BasedCatalysts for H2

[0016] Production from Ammonia:Effect of 1D Support,Topics in Catalysis,62(2019)1169-1177. Summary of the Invention

[0017] The present disclosure provides a catalyst for hydrogen production by ammonia decomposition, a preparation method thereof, and an application thereof, so as to solve at least one of the technical problems existing in the prior art.

[0018] According to a first aspect of the present disclosure, there is provided a catalyst for hydrogen production by ammonia decomposition.

[0019] A catalyst for hydrogen production by ammonia decomposition, the catalyst comprising a palygorskite support and an active component supported thereon, the active component being ruthenium and / or nickel.

[0020] In an implementable embodiment, when the active component is ruthenium, the content of ruthenium accounts for 0.5-5 wt% of the mass of the catalyst;

[0021] or, when the active component is nickel, the content of nickel accounts for 1-10 wt% of the mass of the catalyst;

[0022] Alternatively, when the active components are ruthenium and nickel, the content of ruthenium accounts for 0.5 - 1 wt% of the catalyst mass, and the molar ratio of ruthenium to nickel is 0.33 - 3:1.

[0023] According to the second aspect of the present disclosure, the present application provides a method for preparing a catalyst for ammonia decomposition to produce hydrogen, comprising the following steps:

[0024] Step 1): According to the mass content values of the active components - ruthenium and attapulgite in the catalyst, respectively prepare a ruthenium precursor and attapulgite, and then add the ruthenium precursor and attapulgite into an organic solvent respectively, stir, and then mix to obtain a mixed suspension;

[0025] Step 2): Stir the mixed suspension to evaporate the organic solvent, dry it, and grind it to obtain a semi-finished product;

[0026] Step 3): Reduce the semi-finished product at 300 °C in H₂ for 3 h to obtain a catalyst for ammonia decomposition to produce hydrogen.

[0027] According to the second aspect of the present disclosure, the present application also provides a method for preparing a catalyst for ammonia decomposition to produce hydrogen, comprising the following steps:

[0028] Step 1): According to the mass content values of the active components and attapulgite in the catalyst, respectively prepare a precursor of the active components and attapulgite, and then add the precursor of the active components and attapulgite into an organic solvent respectively, stir, and then mix to obtain a mixed suspension;

[0029] Step 2): Stir the mixed suspension to evaporate the organic solvent, dry it, grind it, and then calcine it in air at 600 °C for 4 h to obtain a semi-finished product;

[0030] Step 3): Reduce the semi-finished product at 300 °C in H₂ for 3 h to finally obtain a catalyst for ammonia decomposition to produce hydrogen;

[0031] Among them, in step 1), the precursor of the active components is a nickel precursor,

[0032] or, the precursor of the active components includes a ruthenium precursor and a nickel precursor.

[0033] In an implementable embodiment, in step 1), the ruthenium precursor is ruthenium chloride, and the nickel precursor is nickel nitrate hexahydrate.

[0034] In an implementable embodiment, in step 1), the organic solvent is one of absolute ethanol and absolute methanol.

[0035] In an implementable embodiment, when the organic solvent is absolute ethanol, the mixed suspension is stirred at 85 °C to evaporate the absolute ethanol;

[0036] When the organic solvent is anhydrous methanol, the mixed suspension is stirred at 65 °C to evaporate the anhydrous methanol.

[0037] According to the third aspect of the present disclosure, the present application provides the use of a catalyst in ammonia decomposition for hydrogen production.

[0038] In one implementable embodiment, the catalyst is used for ammonia decomposition to produce hydrogen, and the ammonia decomposition reaction is carried out in an NH3 atmosphere at 400 - 650 °C.

[0039] In one implementable embodiment, in the ammonia decomposition reaction for hydrogen production, the ammonia gas flow rate is 10 sccm, and the mass space velocity of the catalyst is

[0040] Compared with the prior art, the advantages of the present application are as follows: 1): The carrier material used in the present application, attapulgite, is easy to obtain and has a low cost; 2): The present application uses natural attapulgite as the carrier material and loads the active components, ruthenium and nickel. The obtained catalyst has excellent catalytic performance in ammonia decomposition for hydrogen production. Attapulgite only needs to load a small amount of active metal components to achieve 100% conversion of ammonia, greatly reducing the cost of ammonia decomposition for hydrogen production; 3) The preparation process of the catalyst in the present application is simple and does not require complex chemical reactions and modification treatments. It only needs to directly impregnate attapulgite with the active component precursor, simplifying the preparation process and being suitable for large-scale production.

[0041] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it used to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. Description of the Drawings

[0042] By referring to the drawings and reading the following detailed description, the above and other purposes, features, and advantages of the exemplary embodiments of the present disclosure will become easily understood. In the drawings, several embodiments of the present disclosure are shown in an exemplary rather than restrictive manner, where:

[0043] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0044] Figure 1 Shows the HRTEM image of the 1Ru / ATP catalyst prepared in Example 1 of the present disclosure;

[0045] Figure 2 Shows the curve of the ammonia decomposition efficiency of the 1Ru / ATP catalyst prepared in Example 1 of the present disclosure varying with temperature;

[0046] Figure 3 Shows the long-term stability diagram of the 1Ru / ATP catalyst prepared in Example 1 of the present disclosure;

[0047] Figure 4 The XRD patterns of attapulgite before and after calcination in the embodiments of the present disclosure are shown;

[0048] Figure 5 The HRTEM image of the RuNi / ATP catalyst prepared in Example 5 of the present disclosure is shown. Detailed implementation manners

[0049] To make the objectives, features, and advantages of the present disclosure more obvious and understandable, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present disclosure.

[0050] Attapulgite (ATP) is a naturally formed one-dimensional nanomaterial, and its deposits are distributed in various countries around the world. In China, the resource reserves are particularly rich. ATP has a large specific surface area and good performance stability. Without modification treatment, ATP is directly impregnated with an active metal precursor solution, which simplifies the preparation process and shortens the preparation cycle of the catalyst.

[0051] In this application, commercial ATP does not require further purification and modification treatment. ATP is in the shape of rods or fibers, has a high specific surface area, and has a nanoporous structure. Therefore, the present invention directly prepares a catalyst using naturally formed ATP, which simplifies the preparation process. And using natural ATP as the catalyst carrier material, because of its rich reserves and easy availability, the cost of the catalyst is significantly reduced.

[0052] Based on this, in a first aspect, the present application provides a catalyst for ammonia decomposition to produce hydrogen. The catalyst includes an attapulgite ATP carrier and an active component loaded thereon, and the active component includes ruthenium and / or nickel.

[0053] Preferably, when the active component is ruthenium, the content of ruthenium accounts for 0.5-5 wt% of the mass of the catalyst;

[0054] Or, when the active component is nickel, the content of nickel accounts for 1-10 wt% of the mass of the catalyst, for example, the content of nickel accounts for 1%, 5%, 8%, 10% of the mass of the catalyst;

[0055] Or, when the active component is ruthenium and nickel, the content of ruthenium accounts for 0.5-1 wt% of the mass of the catalyst, and the molar ratio of ruthenium to nickel is 0.33-3:1.

[0056] In this application, natural attapulgite ATP is used as the carrier material for ruthenium / nickel loading in ammonia decomposition to hydrogen. This not only reduces the catalyst cost but also maintains long-term activity. The high specific surface area, good thermal stability, and naturally formed rod-like or fibrous structure of ATP improve the dispersion of ruthenium / nickel nanoparticles, making it an excellent low-cost nanocarrier material.

[0057] Among them, after attapulgite ATP is calcined at 400 °C, 500 °C, and 600 °C, the XRD is used to measure the patterns of attapulgite before and after calcination. The results are as Figure 4 shown. It can be seen from Figure 4 that there is no significant change in the crystal structure of ATP before and after calcination. This indicates that natural attapulgite ATP has good thermal stability.

[0058] Second, this application provides a preparation method for a catalyst used in ammonia decomposition to hydrogen, including the following steps:

[0059] Step 1): According to the mass content values of the active components - ruthenium and attapulgite in the catalyst, ruthenium precursor and attapulgite are respectively prepared, and then the ruthenium precursor and attapulgite are respectively added to an organic solvent, stirred, and then mixed to obtain a mixed suspension;

[0060] Step 2): Stir the mixed suspension to evaporate the organic solvent, dry it, and grind it to obtain a semi-finished product;

[0061] Step 3): Reduce the semi-finished product at 300 °C with H2 for 3 h to obtain a catalyst for ammonia decomposition to hydrogen.

[0062] Preferably, the mass ratio of the ruthenium precursor to attapulgite is 0.0104 - 0.1079:1. More preferably, the ruthenium precursor is ruthenium chloride.

[0063] Preferably, in step 1), the organic solvent is one of anhydrous ethanol and methanol. Among them, when the organic solvent is anhydrous ethanol, the mixed suspension is stirred at 85 °C to evaporate the anhydrous ethanol; when the organic solvent is anhydrous methanol, the mixed suspension is stirred at 65 °C to evaporate the anhydrous methanol.

[0064] On the other hand, we also provide a preparation method when the active component in the catalyst is Ni or Ru-Ni alloy.

[0065] Specifically, a preparation method for a catalyst used in ammonia decomposition to hydrogen, including the following steps:

[0066] Step 1): According to the mass content values of the active component in the catalyst and attapulgite, prepare the precursor of the active component and attapulgite respectively. Then add the precursor of the active component and attapulgite into an organic solvent respectively, stir, and then mix to obtain a mixed suspension;

[0067] Step 2): Stir the mixed suspension to evaporate the organic solvent, dry, grind, and then calcine in air at 600 °C for 4 h to obtain a semi-finished product;

[0068] Step 3): Reduce the semi-finished product at 300 °C with H2 for 3 h to finally obtain a catalyst for ammonia decomposition to produce hydrogen;

[0069] Among them, in Step 1), the precursor of the active component is a nickel precursor,

[0070] Or, the precursor of the active component includes a ruthenium precursor and a nickel precursor.

[0071] Preferably, when the precursor of the active component is a nickel precursor, the mass ratio of the nickel precursor to attapulgite is 0.055 - 0.5505:1.

[0072] Preferably, in Step 1), the ruthenium precursor is ruthenium chloride and the nickel precursor is nickel nitrate hexahydrate.

[0073] Preferably, the organic solvent is one of anhydrous ethanol and methanol. Among them, when the organic solvent is anhydrous ethanol, the mixed suspension is stirred at 85 °C to evaporate the anhydrous ethanol; when the organic solvent is anhydrous methanol, the mixed suspension is stirred at 65 °C to evaporate the anhydrous methanol.

[0074] In the third aspect, the present application provides the application of the catalyst in ammonia decomposition to produce hydrogen.

[0075] Preferably, the catalyst is used in the ammonia decomposition to produce hydrogen process, and the ammonia decomposition to produce hydrogen reaction is carried out at 400 - 650 °C in an NH3 atmosphere. In the ammonia decomposition to produce hydrogen reaction, the ammonia gas flow rate is 10 sccm, and the mass space velocity of the catalyst is

[0076] The following further describes the present application in detail with specific examples.

[0077] The materials and reagents used in the present application can be obtained through commercial channels without special instructions.

[0078] Example 1

[0079] A preparation method of a catalyst for ammonia decomposition to produce hydrogen, including the following steps:

[0080] Step 1): Dissolve 0.0207 g of RuCl3 and disperse 1 g of attapulgite ATP in 20 ml of absolute ethanol respectively. After stirring with a magnetic stirrer for 5 min, mix the two to obtain a mixed suspension of RuCl3 and ATP.

[0081] Step 2): Stir the mixed suspension on a magnetic stirrer at 85 °C until the absolute ethanol completely evaporates, then put it into an oven and dry it for 24 h, and then grind it to obtain a semi-finished product.

[0082] Step 3): Reduce the semi-finished product at 300 °C with H2 for 3 h to obtain a catalyst for ammonia decomposition to produce hydrogen, in which the ruthenium content accounts for 1 wt% of the catalyst mass, that is, it is represented by 1Ru / ATP.

[0083] Observe the morphology of the 1Ru / ATP reduced by hydrogen through HRTEM (transmission electron microscope). As Figure 1 shown. Figure 1 (a) shows a single ATP, its length is about 1 μm, the diameter is about 30 nm, and it mainly exists in the form of aggregates or rod crystal bundles. Figure 1 (b)- Figure 1 (c) shows the unevenness on the surface of ATP, with a certain undulation, and dark ruthenium nanoparticles of different sizes are distributed on the surface. Figure 1 (d) is Figure 1 (c) The local enlarged view in, from Figure 1 (d) it can be seen that the measured value of the diffraction fringe spacing of the selected particles is It belongs to the diffraction of the (002) crystal plane of ruthenium. Thus, it can be known that the catalyst 1Ru / ATP of the present application is successfully prepared.

[0084] Test the ammonia decomposition performance of the 1Ru / ATP catalyst prepared in Example 1 in an ammonia decomposition fixed-bed reactor.

[0085] The specific test method is as follows: When filling the catalyst, measure 0.1 g of the 1Ru / ATP catalyst and about 0.1 g of 3 μm quartz wool, mechanically mix the two, and then place them in a quartz glass tube with an inner diameter of 5 mm. Appropriate quartz wool is additionally stuffed at both ends to prevent the catalyst particles from being blown into the pipeline by the air flow. Raise the temperature to 400 °C for ammonia decomposition performance test, and pure ammonia gas is used as the test gas, and the flow rate is controlled at 10 sccm (corresponding to the mass space velocity of ), and the tail gas at the outlet is tested for the decomposition rate of ammonia under the catalysis of 1Ru / ATP by an ammonia decomposition rate analyzer. The test temperature range is 400 - 600 °C, and it is stable for 30 - 40 min at each test temperature. In the blank experiment, 0.1 g of 3 μm quartz wool is filled in the packing bed, and other processes are the same as those in the test process of the 1Ru / ATP catalyst. The test results are as Figure 2 shown.

[0086] Figure 2 Show the curve of the ammonia decomposition efficiency of 1Ru / ATP varying with temperature. The test gas is pure ammonia, and the mass space velocity is controlled to be Among them, the blank control group (quartz wool) shows that the decomposition rate of ammonia is less than 2% below 600 °C. After ammonia is catalyzed by 1Ru / ATP, the ammonia decomposition rates reach 8%, 24%, 51%, 82% and 100% at 400 °C, 450 °C, 500 °C, 550 °C and 600 °C respectively.

[0087] In addition, the long-term stability of the catalyst 1Ru / ATP was also tested, and the results are as Figure 3 shown. Figure 3 Show the long-term stability of the catalyst 1Ru / ATP (ammonia decomposition at 600 °C). It can be seen that after 1Ru / ATP catalyzes ammonia for up to 150 h, it still maintains a high activity. Linear fitting shows that the decay rate is 0.01% h -1 .

[0088] Example 2

[0089] The preparation method of this Example 2 is generally the same as that of Example 1, except that: in step 1), the mass of RuCl3 is 0.0104 g, and the mass of ATP is 1 g.

[0090] In the catalyst prepared in Example 2, the ruthenium content accounts for 0.5 wt% of the catalyst mass, and is represented by 0.5Ru / ATP.

[0091] Example 3

[0092] The preparation method of this Example 3 is generally the same as that of Example 1, except that: in step 1), the mass of RuCl3 is 0.1079 g, and the mass of ATP is 1 g.

[0093] In the catalyst prepared in Example 2, the ruthenium content accounts for 5 wt% of the catalyst mass, and is represented by 5Ru / ATP.

[0094] Example 4

[0095] A preparation method of a catalyst for ammonia decomposition to produce hydrogen, comprising the following steps:

[0096] Step 1): Dissolve 0.5505 g of nickel nitrate hexahydrate and disperse 1 g of attapulgite ATP in 20 ml of absolute ethanol respectively. After stirring with a magnetic stirrer for 5 min, mix the two to obtain a mixed suspension;

[0097] Step 2): Stir the mixed suspension on a magnetic stirrer at 85 °C until the absolute ethanol completely evaporates, then place it in an oven and dry for 24 h, then grind it, and calcine it in air at 600 °C for 4 h to obtain a semi-finished product;

[0098] Step 3): Reduce the semi-finished product at 300 °C with H2 for 3 h to obtain a catalyst for ammonia decomposition to produce hydrogen, where the nickel content accounts for 10 wt% of the catalyst mass, that is, it is represented by 10Ni / ATP.

[0099] Example 5

[0100] The preparation of this Example 5 is generally the same as that of Example 4, the difference is that: in Step 1), nickel nitrate hexahydrate is 0.055 g and ATP is 1 g. The nickel content accounts for 1 wt% of the catalyst mass, that is, it is represented by 1Ni / ATP.

[0101] Example 6

[0102] A preparation method of a catalyst for ammonia decomposition to produce hydrogen includes the following steps:

[0103] Step 1): Dissolve and disperse 0.0207 g of RuCl3, 0.0291 g of nickel nitrate hexahydrate and 1 g of attapulgite ATP in 20 ml of absolute ethanol respectively. After stirring with a magnetic stirrer for 5 min, mix the three to obtain a mixed suspension;

[0104] Step 2): Stir the mixed suspension on a magnetic stirrer at 85 °C until the absolute ethanol completely evaporates, then place it in an oven and dry for 24 h, then grind it, and calcine it in air at 600 °C for 4 h to obtain a semi-finished product;

[0105] Step 3): Reduce the semi-finished product at 300 °C with H2 for 3 h to obtain a catalyst for ammonia decomposition to produce hydrogen, where the ruthenium content accounts for 1 wt% of the catalyst mass, and the molar ratio of nickel to ruthenium is 1:1. The prepared catalyst is represented by RuNi / ATP.

[0106] Observe the morphology of the RuNi / ATP prepared in this Example 6 by HRTEM (transmission electron microscope). The results are as Figure 5 shown. According to Figure 5 (a) and (b), the morphology of ATP has no obvious change, but some lump-like particles appear. Analyze these particles respectively, and the results are as Figure 5 (c)-(f) shown, the (002) and (100) crystal planes of Ru are identified, but due to the close spacing between the (111) crystal plane of Ni and the (101) crystal plane of Ru Therefore, it cannot be distinguished only by HRTEM. Although some crystal planes cannot be determined, it can be seen that for RuNi / ATP calcined at 600 °C and reduced at 300 °C, the metal nanoparticles have grown significantly, and the particle size far exceeds 5 nm. According to the literature, the ammonia decomposition activity is closely related to the particle size of Ru. When the particle size of Ru is 2 - 5 nm, the number of B5 catalytic active sites is the largest. Therefore, for RuNi / ATP, the coarsening of the nanoparticles should be the reason for the performance degradation of RuNi / ATP.

[0107] Furthermore, combining Figure 1 with the HRTEM images of the 1Ru / ATP catalyst in

[0108] Example 7

[0109] According to the preparation method of Example 6, the dosages of RuCl3 and nickel nitrate hexahydrate were adaptively changed with the molar ratio of ruthenium to nickel in the catalyst being 0.33 - 3:1. Thus, RuNi2 / ATP catalyst (molar ratio of ruthenium to nickel is 0.5:1), RuNi3 / ATP catalyst (molar ratio of Ru:Ni is 0.33:1), Ru2Ni / ATP catalyst (molar ratio of Ru:Ni is 2:1), and Ru3Ni / ATP catalyst (molar ratio of Ru:Ni is 3:1) were respectively prepared. Among the RuNi2 / ATP catalyst, RuNi3 / ATP catalyst, Ru2Ni / ATP catalyst, and Ru3Ni / ATP catalyst, the Ru content accounts for 1 wt% of the catalyst mass.

[0110] The Ru x Ni y / ATP catalysts prepared in Examples 6 - 7 were subjected to ammonia decomposition performance experiments, and the results are listed in Table 1.

[0111] Table 1 Results of ammonia decomposition performance experiments of Ru x Ni y / ATP catalysts

[0112]

[0113]

[0114] As can be seen from Table 1, for the Ru x Ni y / ATP series catalysts with added Ni, only less Ru needs to be loaded to achieve 100% ammonia decomposition. This shows that the addition of Ni has a positive impact on the catalytic performance of the catalyst.

[0115] The catalysts prepared in the above embodiments and the catalysts prepared by loading ruthenium on other carrier materials in the prior art were subjected to ammonia decomposition performance experiments, and the results are listed in Table 2.

[0116] Table 2 Catalytic performance results of catalysts for ammonia decomposition

[0117]

[0118]

[0119] As can be seen from Table 1, for the 1Ru / ATP in this Example 1, the ammonia conversion rate can reach 100% at 600 °C. When ruthenium is loaded on other carrier materials, the content of ruthenium increases significantly. Especially when using carbon nanotubes (CNTs) as the carrier, the content of ruthenium needs to be 2.03% to achieve 100% conversion of ammonia, and the price of carbon nanotubes is very expensive. When ruthenium is loaded on Al2O3 nanorods, the content of ruthenium needs to be as high as 7% to make the ammonia conversion rate reach 100%. It can be seen that whether using expensive carbon nanotubes to load ruthenium or using Al2O3 nanorods to load a higher content of ruthenium, the same effect as that of this application can be achieved. However, due to the high costs of ruthenium and these carrier materials, the production cost of the catalyst increases greatly. In this application, attapulgite ATP is used as the carrier material, and only by loading at least 0.5% Ru can 100% conversion of ammonia be achieved, and the production cost of ATP is relatively low, thus greatly reducing the production cost of the catalyst.

[0120] It should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this disclosure, "a plurality" means two or more unless otherwise specifically defined.

[0121] The above is only the specific implementation manner of this disclosure, but the protection scope of this disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by this disclosure can easily think of changes or substitutions, which should all be covered within the protection scope of this disclosure. Therefore, the protection scope of this disclosure should be subject to the protection scope of the claimed rights.

Claims

1. A catalyst for ammonia decomposition to produce hydrogen, characterized in that: The catalyst includes attapulgite support and the active components supported thereon, and the active components are ruthenium and / or nickel.

2. The catalyst according to claim 1, characterized in that: When the active component is ruthenium, the content of ruthenium accounts for 0.5 - 5 wt% of the catalyst mass; Or, when the active component is nickel, the content of nickel accounts for 1 - 10 wt% of the catalyst mass; Or, when the active components are ruthenium and nickel, the content of ruthenium accounts for 0.5 - 1 wt% of the catalyst mass, and the molar ratio of ruthenium to nickel is 0.33 - 3:

1.

3. The preparation method of a catalyst for ammonia decomposition to produce hydrogen according to claim 1 or 2, characterized in that: It includes the following steps: Step 1): According to the mass content values of the active component - ruthenium and attapulgite in the catalyst, ruthenium precursor and attapulgite are respectively prepared, and then the ruthenium precursor and attapulgite are respectively added into an organic solvent, stirred, and then mixed to obtain a mixed suspension; Step 2): Stir the mixed suspension to evaporate the organic solvent, dry it, and grind it to obtain a semi-finished product; Step 3): Reduce the semi-finished product at 300 °C in H₂ for 3 h to obtain a catalyst for ammonia decomposition to produce hydrogen.

4. The preparation method of a catalyst for ammonia decomposition to produce hydrogen according to claim 1 or 2, characterized in that: It includes the following steps: Step 1): According to the mass content values of the active component and attapulgite in the catalyst, the precursor of the active component and attapulgite are respectively prepared, and then the precursor of the active component and attapulgite are respectively added into an organic solvent, stirred, and then mixed to obtain a mixed suspension; Step 2): Stir the mixed suspension to evaporate the organic solvent, dry it, grind it, and then calcine it in air at 600 °C for 4 h to obtain a semi-finished product; Step 3): Reduce the semi-finished product at 300 °C in H₂ for 3 h to finally obtain a catalyst for ammonia decomposition to produce hydrogen; Among them, in Step 1), the precursor of the active component is a nickel precursor, Or, the precursor of the active component includes a ruthenium precursor and a nickel precursor.

5. The preparation method according to claim 3 or 4, characterized in that: In Step 1), the ruthenium precursor is ruthenium chloride, and the nickel precursor is nickel nitrate hexahydrate.

6. The preparation method according to claim 3 or 4, characterized in that: In Step 1), the organic solvent is one of anhydrous ethanol and anhydrous methanol.

7. The preparation method according to claim 6, wherein: When the organic solvent is anhydrous ethanol, the mixed suspension is stirred at 85 °C to evaporate the anhydrous ethanol; When the organic solvent is anhydrous methanol, the mixed suspension is stirred at 65 °C to evaporate the anhydrous methanol.

8. Application of the catalyst according to Claim 1 or 2 in ammonia decomposition to produce hydrogen.

9. The application according to claim 8, characterized in that: Use the catalyst in ammonia decomposition to produce hydrogen, and carry out the ammonia decomposition to produce hydrogen reaction in an NH₃ atmosphere at 400 - 650 °C.

10. The application according to claim 9, wherein: In the ammonia decomposition reaction for hydrogen production, the ammonia gas flow rate is 10 sccm, and the mass space velocity of the catalyst is

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