Perovskite type catalytic material for hydrogen production by ammonia decomposition and preparation method thereof

Abstract

The application provides a perovskite type catalytic material for hydrogen production by ammonia decomposition and a preparation method thereof. The perovskite type catalytic material is LaMO3 (M=Fe, Co, Ni), which is both an active phase precursor and a structural carrier. Under a reducing atmosphere, Fe / Co / Ni can be controlled to be precipitated from the perovskite lattice to form superfine, highly dispersed and lattice-anchored metal nanoparticles, and the active site density is much higher than that of a traditional supported catalyst. In addition, there is strong electron transfer and structural anchoring between the La-O skeleton and the precipitated metal, which significantly improves the metal dispersion and thermal stability, inhibits high-temperature sintering, and makes the catalyst have stronger N-H bond breaking ability. When the catalyst is used for catalyzing the ammonia decomposition reaction for hydrogen production, the ammonia conversion rate is not less than 95%. Furthermore, based on the high-temperature resistance of the perovskite skeleton, the metal particles precipitated after reduction are lattice-anchored, and therefore, the catalyst has strong sintering resistance and agglomeration resistance and can be stably operated for hundreds to thousands of hours.

Description

Technical Field

[0001] This invention relates to the field of ammonia decomposition for hydrogen production technology, and particularly to a perovskite-type catalytic material for ammonia decomposition for hydrogen production and its preparation method. Background Technology

[0002] Hydrogen energy, as the most promising clean energy source in the 21st century, continues to rise in strategic importance against the backdrop of global energy transition. Current technological breakthroughs have made it possible to achieve low-carbon emissions throughout the entire life cycle of hydrogen energy, but technological bottlenecks in storage and transportation severely restrict its large-scale application. Specifically, hydrogen needs to be stored and transported under ultra-low temperatures of -253 ℃ or high pressures of 20 MPa, resulting in persistently high energy costs.

[0003] Against this backdrop, ammonia as a hydrogen energy carrier demonstrates unique advantages. Ammonia molecules have a high hydrogen content of 17.7 wt.% and a liquefaction temperature of only -33 ℃, significantly reducing storage and transportation costs. These characteristics make it a key link connecting renewable energy-based hydrogen production with end-use applications, constructing a zero-carbon cycle system of "green electricity hydrogen production - clean ammonia synthesis - distributed hydrogen supply".

[0004] However, ammonia decomposition for hydrogen production still faces core challenges. For example, traditional non-precious metal supported catalysts for thermocatalytic ammonia decomposition need to operate at high temperatures of 600 ℃-800 ℃, resulting in high energy consumption and poor equipment tolerance. On the other hand, although traditional precious metal ruthenium-based catalysts exhibit excellent activity at medium and low temperatures, their high cost seriously hinders the commercialization process.

[0005] Therefore, it is of great significance to develop inexpensive, efficient and stable non-noble transition metal catalysts for ammonia decomposition reactions. Summary of the Invention

[0006] To address the problems existing in the background technology, the present invention provides a perovskite-type catalytic material for ammonia decomposition to produce hydrogen and its preparation method. The perovskite-type oxide formed by non-precious metals Fe / Co / Ni and rare earth metal La is used as a catalytic material for ammonia decomposition to produce hydrogen, which has the characteristics of high catalytic activity and low cost.

[0007] The specific details of the invention are as follows: In a first aspect, the present invention provides a perovskite-type catalyst for hydrogen production by ammonia decomposition, wherein the perovskite-type catalyst is LaMO3; wherein M is selected from at least one of Fe, Co and Ni; The perovskite-type catalytic material is used to catalyze the decomposition of ammonia to produce hydrogen, with an ammonia conversion rate of not less than 95%.

[0008] Optionally, the perovskite-type catalyst required for catalytic ammonia decomposition to produce hydrogen is a reaction temperature of 400 ℃-600 ℃, a reaction pressure of 0.1 MPa-5 MPa, and a reaction space velocity of 3000 mL·g.-1 ·h -1 -30000 mL·g -1 ·h -1 .

[0009] Optionally, the catalytic ammonia decomposition to hydrogen production reaction is carried out in a fixed bed or a fluidized bed.

[0010] Optionally, the perovskite-type catalytic material, after pre-activation treatment, is used to catalyze the ammonia decomposition to produce hydrogen.

[0011] In a second aspect, the present invention provides a method for preparing the perovskite-type catalytic material for hydrogen production by ammonia decomposition as described in the first aspect above, the preparation method comprising: The precursor salts of La and M are dissolved in deionized water and mixed to form a mixed solution. Citric acid is added to the mixed solution and stirred continuously to form a sol. Heating the sol causes the solvent to evaporate, resulting in a fluffy gel; The gel is crushed and ground, then transferred to a high-temperature environment for high-temperature calcination to obtain the perovskite-type catalytic material.

[0012] Optionally, the precursor salt of La is selected from La-containing nitrates or M-containing acetates; The precursor salt of M is selected from nitrates containing M or acetates containing M.

[0013] Optionally, the concentration of total metal ions in the mixed solution is 5-20 wt.%.

[0014] Optionally, in the mixed solution, the molar ratio of citric acid to total metal ions is 1.2 to 1.5.

[0015] Optionally, the continuous stirring to form the sol is carried out at 60 ℃-80 ℃; The temperature at which the solvent evaporates from the sol is heated is 120 ℃-150 ℃.

[0016] Optionally, the high-temperature calcination includes: The temperature was increased to 800-1000℃ at a heating rate of 5-10℃ / min, and held for 2-4 hours.

[0017] Compared with the prior art, the present invention has the following advantages: This invention provides a perovskite-type catalyst for ammonia decomposition to produce hydrogen, wherein the perovskite-type catalyst is LaMO3; wherein M is selected from at least one of Fe, Co and Ni; the perovskite-type catalyst is used to catalyze the ammonia decomposition to produce hydrogen, and the catalyst has the advantages of convenient preparation process and low cost, as well as excellent catalytic performance, which can meet the activity and stability requirements under ammonia decomposition environment. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating the preparation method of the perovskite-type catalyst for hydrogen production from ammonia decomposition provided in this embodiment of the invention is shown. Figure 2 Transmission electron microscopy (TEM) images of the perovskite-type catalytic material provided in embodiments of the present invention are shown. Figure 3 The EDS elemental analysis diagram of the perovskite-type catalyst provided in the embodiments of the present invention is shown. Figure 4 The following is an EDS elemental analysis diagram of a perovskite-type catalyst provided in another embodiment of the present invention; Figure 5 The following is an EDS elemental analysis diagram of a perovskite-type catalyst provided in another embodiment of the present invention; Figure 6 The XRD phase analysis spectrum of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic material provided in the embodiments of the present invention is shown. Figure 7 The ammonia conversion rates of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic materials provided in Examples 1-3 of the present invention are shown at preferred temperatures. Figure 8 The relationship between ammonia conversion rate and temperature of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic materials provided in Examples 1-3 of this invention is shown. Figure 9 The ammonia decomposition performance diagram of the perovskite-type catalytic material provided in the embodiments of the present invention is shown. Figure 10 The effect of reaction pressure on the ammonia decomposition performance of the perovskite-type catalyst provided in the embodiments of the present invention is shown. Figure 11 The effect of space velocity on ammonia decomposition performance of the perovskite-type catalytic material provided in the embodiments of the present invention is shown. Figure 12 The diagram shows the long-cycle ammonia decomposition performance of the perovskite-type catalytic material provided in the embodiments of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of the present invention.

[0021] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0022] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of this specification.

[0023] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] Existing non-precious metal supported ammonia decomposition hydrogen production catalysts are mainly Ni-based, supplemented by Co-based and Fe-based catalysts. The active sites are regulated by metal-support interaction (SMSI), which continuously improves activity and stability on the basis of cost advantage. However, they still face core challenges such as complicated preparation process, high-temperature sintering of catalyst, carbon deposition and deactivation, and imbalance of metal-support interaction.

[0025] Therefore, this invention provides a novel approach to constructing a catalytic material for hydrogen production from ammonia decomposition. Specifically, it uses La as the promoter metal component and non-noble metals Fe, Co, and Ni as the active metal components. By constructing a perovskite structure LaMO3 (M=Fe, Co, Ni), the catalyst exhibits stronger NH bond-breaking ability by leveraging the electronic promoter La's influence on the active metals Fe, Co, and Ni. The perovskite structure LaMO3 (M=Fe, Co, Ni) itself serves as both an active phase precursor and a structural support, eliminating the need for multiple steps such as support selection, loading, and calcination, simplifying the process and reducing preparation costs. Furthermore, after deactivation, this catalytic material can restore its perovskite structure and activity through a redox cycle, with regeneration costs far lower than those of supported catalysts, significantly reducing the catalyst's total lifecycle cost. The specific embodiments of this invention are described in detail below: In a first aspect, the present invention provides a perovskite-type catalyst for hydrogen production by ammonia decomposition, wherein the perovskite-type catalyst is LaMO3; wherein M is selected from at least one of Fe, Co and Ni.

[0026] In this embodiment of the invention, the perovskite-type catalyst LaMO3 (M=Fe, Co, Ni) is both an active phase precursor and a structural support. Under a reducing atmosphere, Fe / Co / Ni can be controllably precipitated from the perovskite lattice to form ultrafine, highly dispersed, lattice-anchored metal nanoparticles with an active site density far higher than that of traditional supported catalysts. Furthermore, there is strong electron transfer and structural anchoring between the La-O framework and the precipitated metal, which significantly improves the metal dispersion and thermal stability, inhibits high-temperature sintering, and gives the catalyst a stronger NH bond-breaking ability. When used to catalyze the decomposition of ammonia to produce hydrogen, the ammonia conversion rate is not less than 95%. Moreover, based on the high-temperature resistance of the perovskite framework, the metal particles precipitated after reduction are lattice-anchored. Therefore, the catalyst has extremely strong anti-sintering and anti-agglomeration capabilities and can operate stably for hundreds to thousands of hours.

[0027] In some implementations, M can be selected from any two or three of Fe, Co and Ni. For example, Fe-Co, Co-Ni, Fe-Ni and Fe-Co-Ni combinations can be introduced into the M site to optimize the binding energy of M and N by utilizing electronic cooperation and geometric effects, thereby significantly improving intrinsic activity.

[0028] In some embodiments, the perovskite-type catalyst is used to catalyze the decomposition of ammonia to produce hydrogen at a reaction temperature of 400 °C–600 °C, a reaction pressure of 0.1 MPa–5 MPa, and a reaction space velocity of 3000 mL·g. -1 ·h -1 -30000 mL·g -1 ·h -1 .

[0029] In practical implementation, traditional supported ammonia decomposition catalysts using non-precious metals such as Ni, Co, and Fe as active components require high temperatures (typically above 600°C) to achieve high ammonia conversion rates due to poor dispersion of active metals, easy sintering and agglomeration, and weak metal-support interactions. In contrast, the perovskite-type catalyst provided in this embodiment can form lattice-anchored, highly dispersed active metal sites in situ under a reducing atmosphere, exhibiting lower activation energy and superior low-temperature catalytic activity. It can catalyze ammonia decomposition at 300°C and achieve high ammonia conversion rates at 500°C–600°C, significantly lower than traditional non-precious metal supported catalysts. The preferred reaction temperature for catalytic ammonia decomposition to hydrogen production in this embodiment is 500°C–600°C, the reaction pressure is 0.1 MPa–1 MPa, and the reaction space velocity is 3000 mL·g. -1 ·h -1 -18000 mL·g -1 ·h -1 .

[0030] In some embodiments, the catalytic ammonia decomposition to hydrogen production reaction is carried out in a fixed bed or a fluidized bed.

[0031] In some embodiments, the perovskite-type catalyst material is pre-activated and then used to catalyze the ammonia decomposition reaction to produce hydrogen.

[0032] In practice, after impurities are removed in an inert atmosphere, the perovskite-type catalyst is placed in a reducing atmosphere and pre-activated for 6-12 h at 500-600℃, 0.1-0.5 MPa, and an ammonia concentration of 10-100 vol.%, so that a highly dispersed metal active phase is generated in situ from the perovskite-type catalyst.

[0033] In practice, perovskite-type catalysts can be packed into a fixed-bed tubular reactor, and 10 mL / min-50 mL / min of 10 vol.%-100 vol.% ammonia gas can be introduced at room temperature. The temperature can be increased to 500℃-600℃ at 5℃ / min-10℃ / min, the pressure range is 0.1 MPa-0.5 MPa, and the pre-activation time is 6 h-12 h.

[0034] Secondly, the present invention provides a method for preparing the perovskite-type catalyst material for hydrogen production by ammonia decomposition as described in the first aspect above. Figure 1 A flowchart illustrating the preparation method of the perovskite-type catalyst for hydrogen production from ammonia decomposition provided in this embodiment of the invention is shown, as follows: Figure 1 As shown, the preparation method includes: S1. Dissolve the precursor salts of La and M in deionized water and mix well to form a mixed solution. Add citric acid to the mixed solution and stir continuously to form a sol. S2. Heat the sol to evaporate the solvent, resulting in a fluffy gel; S3. The gel is crushed and ground, and then transferred to a high-temperature environment for high-temperature calcination to obtain the perovskite-type catalyst material.

[0035] In some embodiments, the precursor salt of La is selected from La-containing nitrates or M-containing acetates, specifically lanthanum nitrate or lanthanum acetate; the precursor salt of M is selected from M-containing nitrates or M-containing acetates, such as ferric nitrate, ferric acetate, cobalt nitrate, cobalt acetate, nickel nitrate, and nickel acetate.

[0036] This embodiment determines the specific amounts of the La precursor salt and the M precursor salt by using the stoichiometric ratio of the metal elements that make up LaMO3. As an example, in the mixed solution, the molar ratio of the La precursor salt to the M precursor salt is 0.7 to 1.3. The resulting mixed solution has a total metal ion concentration of 5-20 wt.%.

[0037] In some embodiments, the molar ratio of citric acid to total metal ions in the mixed solution is 1.2 to 1.5.

[0038] In some embodiments, the continuous stirring to form the sol is carried out at 60-80 °C; The temperature at which the solvent evaporates from the sol is heated is 120 ℃-150 ℃.

[0039] In some embodiments, the high-temperature calcination includes: The temperature was increased to 800-1000 ℃ at a heating rate of 5-10 ℃ / min, and held at that temperature for 2-4 h.

[0040] To enable those skilled in the art to more clearly understand the present invention, the following embodiments are provided to illustrate in detail a perovskite-type catalyst for hydrogen production from ammonia decomposition and its preparation method.

[0041] Example 1 Weigh 4.33 g of lanthanum nitrate hexahydrate and 4.04 g of ferric nitrate nonahydrate, respectively, and dissolve them in 80 mL of deionized water. Stir magnetically at room temperature for 2 hours. Weigh 4.61 g of citric acid and dissolve it in the above solution. Continue stirring magnetically at room temperature for 2 hours. Heat and stir the resulting solution to form a sol; the stirring speed is 600 rpm, the stirring temperature is 80 ℃, and the stirring time is 4-6 hours.

[0042] The obtained sol was removed and placed in an evaporating dish, then placed in an oven at 150 °C for 8 h to obtain a fluffy gel.

[0043] The obtained gel was crushed and ground, placed in a porcelain boat and calcined in a muffle furnace. The temperature was increased to 800 °C at a rate of 10 °C / min and held at that temperature for 4 h. After cooling, the perovskite-type LaFeO3 catalyst material was obtained.

[0044] Example 2 Weigh 4.33 g of lanthanum nitrate hexahydrate and 2.91 g of cobalt nitrate hexahydrate, respectively, and dissolve them in 80 mL of deionized water. Stir magnetically at room temperature for 2 h. Weigh 4.61 g of citric acid and dissolve it in the above solution. Continue stirring magnetically at room temperature for 2 h. Heat and stir the resulting solution to form a sol at 600 rpm and 80 °C for 4 h.

[0045] The obtained sol was removed and placed in an evaporating dish, then placed in an oven at 150 °C for 8 h to obtain a fluffy gel.

[0046] The obtained gel was crushed and ground, placed in a porcelain boat and calcined in a muffle furnace. The temperature was increased to 800 °C at a rate of 10 °C / min and held at that temperature for 4 h. After cooling, the perovskite-type LaCoO3 catalyst material was obtained.

[0047] Example 3 Weigh 4.33 g of lanthanum nitrate hexahydrate and 2.91 g of nickel nitrate nonahydrate, respectively, and dissolve them in 80 mL of deionized water. Stir magnetically at room temperature for 2 h. Weigh 4.61 g of citric acid and dissolve it in the above solution. Continue stirring magnetically at room temperature for 2 h. Heat and stir the resulting solution to form a sol at 600 rpm and 80 °C for 4 h.

[0048] The obtained sol was removed and placed in an evaporating dish, then placed in an oven at 150 °C for 8 h to obtain a fluffy gel.

[0049] The obtained gel was crushed and ground, placed in a porcelain boat and calcined in a muffle furnace. The temperature was increased to 800 °C at a rate of 10 °C / min and held at that temperature for 4 h. After cooling, the perovskite-type LaNiO3 catalyst material was obtained.

[0050] Comparative Example 1 Weigh 4.33 g of lanthanum nitrate hexahydrate and dissolve it in 80 mL of deionized water. Stir magnetically at room temperature for 2 h. Weigh 2.34 g of citric acid and dissolve it in the above solution. Continue stirring magnetically at room temperature for 2 h. Heat and stir the resulting solution to form a sol at 600 rpm and 80 °C for 4 h.

[0051] The obtained sol was removed and placed in an evaporating dish, then placed in an oven at 150 °C for 8 h to obtain a fluffy gel.

[0052] The obtained gel was crushed and ground, placed in a porcelain boat and calcined in a muffle furnace. The temperature was increased to 800 °C at a rate of 10 °C / min and held at that temperature for 4 h. After cooling, La2O3 was obtained.

[0053] Comparative Example 2 Weigh 2.91 g of nickel nitrate nonahydrate and dissolve it in 80 mL of deionized water. Stir magnetically at room temperature for 2 h. Weigh 2.34 g of citric acid and dissolve it in the above solution. Continue stirring magnetically at room temperature for 2 h. Heat and stir the resulting solution to form a sol at 600 rpm and 80 °C for 4 h.

[0054] The obtained sol was removed and placed in an evaporating dish, then placed in an oven at 150 °C for 8 h to obtain a fluffy gel.

[0055] The obtained gel was crushed and ground, placed in a porcelain boat and calcined in a muffle furnace. The temperature was increased to 800 °C at a rate of 10 °C / min and held at that temperature for 4 h. After cooling, NiO was obtained.

[0056] Comparative Example 3 Comparative catalyst 3 is a commercially available industrial nickel-based Ni / Al2O3-SiO2 catalyst (manufacturer: Thermo Fisher Scientific, catalog number 031276-22, production batch number 031276, nickel content 64.0 wt.%).

[0057] Figure 2 Transmission electron microscopy (TEM) images of the perovskite-type catalytic material provided in embodiments of the present invention are shown, as follows: Figure 2 As shown, the catalyst exhibits a particulate structure.

[0058] Figure 3-5 The EDS elemental analysis diagram of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic material provided in the embodiments of the present invention is shown.

[0059] Figure 6 The XRD phase analysis spectrum of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic material provided in the embodiments of the present invention is shown, as follows: Figure 6 As shown, the diffraction peaks of LaFeO3, LaCoO3, and LaNiO3 are clearly visible, indicating that the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic material has been successfully prepared.

[0060] Performance testing The performance of the catalytic materials prepared in Examples 1-3 and Comparative Examples 1-3 for hydrogen production by ammonia decomposition was tested.

[0061] (1) Pre-activation A perovskite-type LaMO3 (M=Fe, Co, Ni) catalyst was loaded into a fixed-bed tubular reactor for catalyst pre-activation. Ammonia gas of 10-100 vol.% was introduced at 50 mL / min at room temperature, and the temperature was increased to 500-600℃ at 5℃ / min. The pressure range was 0.1-0.5 MPa, and the pre-activation time was 6-12 h.

[0062] (2) Hydrogen production from ammonia decomposition Nitrogen gas was introduced at a flow rate of 50 mL / min at room temperature, and the temperature was increased to 500 °C at a rate of 5 °C / min. After stabilizing at 500 °C for 1 hour, the reaction gas was introduced to test the ammonia decomposition performance. The ammonia in the product gas was absorbed by dilute sulfuric acid and then detected by ion chromatography. The reaction space velocity was 3000-30000 mL·g. -1 ·h -1 The reaction temperature range is 200-500 ℃, the reaction pressure range is 0.1-1.0 MPa, and the ammonia concentration range is 10-100 vol.%.

[0063] Figure 7 The ammonia conversion of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalysts provided in Examples 1-3 of this invention is shown at a preferred temperature (reaction conditions: reaction temperature 500 °C, reaction pressure 0.1 MPa, ammonia concentration 10 vol.%, reaction space velocity 6000 mL·g). -1 ·h -1 ),like Figure 7 As shown, the ammonia conversion rates of the perovskite-type LaFeO3, LaCoO3 and LaNiO3 catalytic materials provided in Examples 1-3 are 95.5%, 95.8% and 99.8%, respectively.

[0064] Figure 8 The relationship between ammonia conversion rate and temperature of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic materials provided in Examples 1-3 of this invention is shown (reaction conditions: reaction temperature 300-600 ℃, reaction pressure 0.1 MPa, ammonia concentration 10 vol.%, reaction space velocity 6000 mL·g). -1 ·h -1 ),like Figure 8 As shown, the ammonia conversion rate of the perovskite-type LaMO3 (M=Fe,Co, Ni) catalysts provided in Examples 1-3 increases rapidly starting at 400 °C, and reaches over 95% at 500 °C.

[0065] Figure 9 The ammonia decomposition performance of the perovskite-type LaNiO3 catalysts provided in Example 3 and Comparative Examples 1-3 of the present invention is compared (reaction conditions: reaction temperature 300-600 °C, reaction pressure 0.1 MPa, ammonia concentration 10 vol.%, reaction space velocity 6000 mL·g). -1 ·h -1 ),like Figure 9 As shown in the comparison between Example 3 and Comparative Example 1, Ni is the active component in the LaNiO3 catalyst, and its role in the ammonia decomposition reaction is essential. As shown in the comparison between Example 3 and Comparative Example 2, La acts as an electronic promoter in the LaNiO3 catalyst, which can effectively improve the catalytic activity. Compared with the industrial nickel-based Ni / Al2O3-SiO2 catalyst, the LaNiO3 catalyst of the present invention has better performance.

[0066] Figure 10 The effect of reaction pressure on the ammonia decomposition performance of the perovskite-type LaNiO3 catalyst provided in the embodiments of the present invention is shown (reaction conditions: reaction temperature 500 °C, reaction pressure 0.1, 0.3, 0.6, 1.0 MPa, ammonia concentration 10 vol.%, reaction space velocity 6000 mL·g). -1 ·h -1 ),like Figure 10 As shown, the ammonia conversion rates at ammonia decomposition reaction pressures of 0.1, 0.3, 0.6, and 1.0 MPa are 99.8%, 97.9%, 94.7%, and 92.6%, respectively.

[0067] Figure 11 The effect of space velocity on ammonia decomposition performance of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic material provided in the embodiments of the present invention is shown (reaction conditions: reaction temperature 500 °C, reaction pressure 0.1 MPa, ammonia concentration 10 vol.%). Figure 11 As shown, the reaction space velocities are (3000, 6000, 12000, 18000) mL·g -1 ·h -1 At that time, the corresponding ammonia conversion rates were 99.9%, 99.8%, 94.9%, and 90.3%, respectively.

[0068] Figure 12 The diagram shows the long-term ammonia decomposition performance of the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic material provided in the embodiments of the present invention (reaction conditions: reaction temperature 500 ℃, reaction pressure 0.1 MPa, ammonia concentration 10 vol.%, reaction space velocity 6000 mL·g). -1 ·h-1 ).like Figure 12 As shown, the ammonia conversion rate of the perovskite-type LaNiO3 catalyst remained above 96% during the 50-hour long-cycle ammonia decomposition performance test.

[0069] In summary, the perovskite-type LaMO3 (M=Fe, Co, Ni) catalytic material provided by this invention has good ammonia decomposition activity, and can achieve an ammonia decomposition conversion rate of not less than 90% at a temperature of 500-600 ℃ and a pressure of 0.1-1 MPa, showing broad prospects for practical application.

[0070] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., 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, the 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. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0071] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0072] The above provides a detailed description of a perovskite-type catalyst for hydrogen production from ammonia decomposition and its preparation method. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A perovskite-type catalyst for hydrogen production from ammonia decomposition, characterized in that, The perovskite-type catalyst is LaMO3; wherein M is selected from at least one of Fe, Co and Ni; The perovskite-type catalytic material is used to catalyze the decomposition of ammonia to produce hydrogen, with an ammonia conversion rate of not less than 90%.

2. The perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 1, characterized in that, The perovskite-type catalyst required for catalytic ammonia decomposition to produce hydrogen is a reaction temperature of 400 ℃-600 ℃, a reaction pressure of 0.1 MPa-5 MPa, and a reaction space velocity of 3000 mL·g. -1 ·h -1 -30000 mL·g -1 ·h -1 .

3. The perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 2, characterized in that, The catalytic ammonia decomposition to produce hydrogen reaction is carried out in a fixed bed or a fluidized bed.

4. The perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 1, characterized in that, The perovskite-type catalytic material, after pre-activation treatment, is used to catalyze the decomposition of ammonia to produce hydrogen.

5. A method for preparing a perovskite-type catalyst for hydrogen production from ammonia decomposition according to any one of claims 1-4, characterized in that, The preparation method includes: The precursor salts of La and M are dissolved in deionized water and mixed to form a mixed solution. Citric acid is added to the mixed solution and stirred continuously to form a sol. Heating the sol causes the solvent to evaporate, resulting in a fluffy gel; The gel is crushed and ground, then transferred to a high-temperature environment for high-temperature calcination to obtain the perovskite-type catalytic material.

6. The method for preparing the perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 5, characterized in that, The precursor salt of La is selected from La-containing nitrates or M-containing acetates; The precursor salt of M is selected from nitrates containing M or acetates containing M.

7. The method for preparing the perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 5, characterized in that, The concentration of total metal ions in the mixed solution is 5-20 wt.%.

8. The method for preparing the perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 5, characterized in that, In the mixed solution, the molar ratio of citric acid to total metal ions is 1.2 to 1.

5.

9. The method for preparing the perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 5, characterized in that, The continuous stirring to form the sol was carried out at 60 ℃-80 ℃; The temperature at which the solvent evaporates from the sol is heated is 120 ℃-150 ℃.

10. The method for preparing the perovskite-type catalyst for hydrogen production from ammonia decomposition according to claim 5, characterized in that, The high-temperature calcination includes: The temperature was increased to 800-1000℃ at a heating rate of 5-10℃ / min, and held for 2-4 hours.

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