Monolithic catalyst based on metal carrier as well as preparation method and application of monolithic catalyst

Abstract

The invention discloses a monolithic catalyst based on a metal carrier, a preparation method and application. The method comprises the following steps: performing alkali / acid ultrasonic cleaning on a metal carrier, drying, forming an oxide layer on the surface of the carrier through gradient oxidation treatment, and finally loading a catalyst layer by adopting an impregnation method, a 3D printing coating method or an electric arc spraying method, surface impurities are removed through alkali etching, and a special oxide layer structure is formed on the surface of the metal carrier in combination with a gradient oxidation process, so that the interface bonding strength of the catalyst and the carrier is remarkably enhanced, and the mass transfer / heat transfer performance is optimized. The method is simple in process and easy for large-scale production, and the prepared catalyst shows excellent catalytic activity and high-temperature stability in ammonia decomposition hydrogen production reaction, and is especially suitable for high-efficiency hydrogen production application under high-temperature conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst equipment, and in particular to a metal carrier-based integral catalyst, a preparation method and application thereof. Background Art

[0002] Catalysts for hydrogen production from ammonia decomposition are primarily categorized as noble metals (such as Ru) and transition metals (such as Ni and Fe). While noble metals exhibit excellent low-temperature activity, they are expensive and require high preparation costs. Improving their dispersion to reduce loading is one cost-effective approach. However, both noble and transition metal catalysts are currently primarily used as powdered catalysts after molding. While molding can reduce pressure drop at high throughputs, it severely limits mass and heat transfer performance. Specifically, heat generated during the reaction cannot be removed promptly, leading to the formation of "hot spots" within the bed, which can lead to safety concerns such as catalyst sintering and deactivation, as well as overheating of the bed. Furthermore, the active sites within the molded catalyst particles are unable to contact the reactants, reducing catalyst utilization. Furthermore, due to their limited morphological characteristics, these catalysts struggle to meet the demands of high-throughput, compact reactors. In recent years, to address these limitations, researchers have proposed metal-supported catalysts, in which the catalyst coating is directly loaded onto a metal support (such as metal foam or metal honeycomb) to enhance thermal conductivity and catalytic activity. Furthermore, modular designs can also meet the requirements of compact reactors. Although metal-supported catalysts have excellent catalytic performance, the bonding strength between the catalyst coating and the metal surface is relatively low, which can easily lead to a high coating peeling rate and a short thermal shock life, thus affecting the catalytic performance and stability. Summary of the Invention

[0003] In view of the defects of metal catalysts in the prior art such as high preparation cost, poor heat and mass transfer performance, easy catalyst deactivation and low catalyst utilization rate, etc., a metal-based integral catalyst with high bonding strength between the catalytic coating and the metal surface, low process complexity and suitability for large-scale application, and excellent ammonia decomposition and hydrogen production performance, a preparation method and application thereof are provided.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a preparation method of an integral catalyst based on a metal carrier, comprising the following steps: step one: placing the carrier material in an alkaline solution or an acidic solution for ultrasonic cleaning; step two: drying the carrier material after ultrasonic cleaning at room temperature; step three: placing the dried carrier material in a heating device and heating the heating device to a first heating temperature to form an oxide layer on the surface of the carrier material; after reaching the first heating temperature, the carrier material is kept heated for 1 to 2 hours; step four: continuing to heat the carrier material with an oxide layer formed on the surface to a second heating temperature, and after reaching the second heating temperature, the carrier material is kept heated for 2 to 4 hours; step five: after completing the continuous heating of the carrier material, gradually cooling to room temperature and cooling the carrier material to obtain a metal carrier; step six: using an impregnation method, 3D printing coating or arc spraying method to load the catalytic layer on the metal carrier to obtain an integral catalyst based on a metal carrier.

[0005] Furthermore, in step one, the carrier material is any one or a combination of stainless steel, iron-chromium alloy, iron-chromium-aluminum alloy, nickel, titanium, aluminum zirconate, aluminum titanate, aluminum phosphate, cordierite, rutile column or corundum; the form of the carrier material is any one of wire mesh, foam, fiber, fiber felt, round tube, and disc.

[0006] Furthermore, when the carrier material is placed in an alkaline solution, the alkaline solution is any one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate, the concentration of the alkaline solution is in the range of 0.001 to 1 mol / L, and the ratio of the carrier material to the alkaline solution is in the range of 0.001 to 1 g / mL; when ultrasonically cleaning the carrier material, the alkaline solution containing the carrier material is set at a temperature range of 30 to 100° C. and ultrasonically cleaned for 0.1 to 5 hours;

[0007] When the carrier material is placed in an acidic solution, the acidic solution is any one or more of dilute sulfuric acid, dilute nitric acid, oxalic acid, and phosphoric acid, the concentration range of the acidic solution is 0.001 to 1 mol / L, and the amount ratio of the carrier material to the acidic solution is 0.001 to 1 g / mL; when ultrasonically cleaning the carrier material, the acidic solution containing the carrier material is set in a temperature range of 30 to 100° C. and ultrasonically cleaned for 0.1 to 5 hours.

[0008] Furthermore, in step three, the heating device is filled with a protective gas, which is nitrogen; the temperature in the heating device is increased to a first heating temperature at a heating rate of 2 to 10°C / min; the first heating temperature is 500 to 700°C; and the heating device is maintained at a temperature of 500 to 700°C for 1 to 2 hours.

[0009] Furthermore, in step 4, the heating device is filled with air, and the temperature inside the heating device is continuously heated to 950-1050° C. at a rate of 2-5° C. / min; the heating device is maintained at a temperature of 950-1050° C. for 2-4 hours.

[0010] Furthermore, in step five, the temperature is first cooled to 500-600° C. at a cooling rate of 1-2° C. / min; and then cooled to room temperature.

[0011] Furthermore, in step six, when the catalytic layer is loaded on the metal support containing the densified oxide layer by the impregnation method; first, an active metal precursor solution containing an active metal is selected, the active metal is ruthenium element, and the active metal precursor solution is any one or more of ruthenium nitrate, ruthenium chloride, ruthenium acetate, chlororuthenic acid, ammonium chlororuthenate, sodium chlororuthenate or potassium chlororuthenate; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, at room temperature, the treated metal support containing the densified oxide layer is reacted with tartaric acid and An equal volume of a mixed solution consisting of an active metal precursor solution is impregnated to obtain a catalyst precursor; the obtained catalyst precursor is dried at a temperature of 30 to 80° C. for 2 to 12 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere at a calcination temperature range of 200 to 600° C. for 0.5 to 24 hours; after the catalyst precursor is calcined, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture at a reduction temperature range of 200 to 600° C. for 0.5 to 24 hours;

[0012] When the catalytic layer is loaded on a metal support containing a densified oxide layer by 3D printing coating, the ruthenium precursor is first dissolved in a tartaric acid auxiliary solution, and the active metal precursor solution is any one or more of ruthenium nitrate, ruthenium chloride, ruthenium acetate, chlororuthenic acid, ammonium chlororuthenate, sodium chlororuthenate or potassium chlororuthenate; then a binder is added, and the binder is one or more of diaspore sol, aluminum colloid, and silica sol; the rheological properties of the solution are adjusted to prepare a 3D printing catalytic ink; the ruthenium loading layer is printed layer by layer on the metal support through a nozzle (50 to 500 μm); the tartaric acid is added. The molar ratio of the acid to the active metal is in the range of 0.5 to 15; the mass of the active metal in the active metal precursor is 0.1 to 0.4 wt% of the mass of the metal support after calcination; the obtained catalyst precursor is calcined in an oxygen-containing atmosphere at a temperature in the range of 200 to 600° C. for a time of 0.5 to 24 hours; after the catalyst precursor is calcined, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture at a temperature in the range of 200 to 600° C. for a time of 0.5 to 24 hours;

[0013] When the catalytic layer is loaded on a metal support containing a densified oxide layer by arc spraying, the treated metal support is placed in an arc spraying system, and an alloy wire or composite wire containing ruthenium is selected as the spraying material; the alloy wire or composite wire containing active metal includes any one or more of ruthenium-nickel alloy wire, ruthenium-aluminum alloy wire, ruthenium-aluminum oxide, and ruthenium-cerium oxide composite wire; the wire diameter ranges from 1 to 3 mm; the ruthenium layer is deposited at an arc power of 2050 kW and a spraying pressure of 0.2 to 0.8 MPa, and the spraying temperature is controlled at 600 to 1200° C. to form a uniform and dense ruthenium loading layer layer by layer; wherein the mass of the active metal in the active metal precursor is 0.1 to 0.4 wt% of the mass of the calcined metal support; the catalyst precursor obtained after spraying is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature ranges from 200 to 600° C., and the reduction time is 0.5 to 24 hours;

[0014] A metal-supported integral catalyst is prepared by a method for preparing a metal-supported integral catalyst.

[0015] The invention discloses an application of a metal-supported monolithic catalyst prepared by a method for preparing a metal-supported monolithic catalyst. The metal-supported monolithic catalyst is applied to the decomposition of ammonia to produce hydrogen.

[0016] The present invention discloses a method for preparing an integral catalyst based on a metal carrier, which effectively improves the ammonia decomposition performance by treating the metal carrier with alkaline etching and gradient oxidation, especially under high temperature conditions, the reaction efficiency of the catalyst is significantly improved; wherein, alkaline etching is used to remove oxides, dirt or other impurities on the surface of the iron-chromium-aluminum metal carrier to provide a cleaner surface; gradient oxidation is a step performed after alkaline etching, and by controlling the degree and depth of oxidation, different oxide layers are formed on the surface of the metal carrier, thereby enhancing the coupling between the metal carrier and the catalyst. The properties of this oxide layer (such as porosity, crystal structure, etc.) contribute to the dispersion of the catalyst and the stability of the active sites; the catalyst layer is strongly bonded to the metal carrier, thereby enhancing the thermal stability of the interface, optimizing the mass transfer / heat transfer performance, and reducing the process complexity, making it suitable for large-scale applications and having excellent ammonia decomposition and hydrogen production performance and stability. DETAILED DESCRIPTION

[0017] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects achieved by this application, the following is a detailed description of the specific embodiments listed. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0018] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0019] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0020] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0021] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0022] Without further limitations, in this application, the words "include", "comprise", "have" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such process, method or product.

[0023] Consistent with the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. Furthermore, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this manner, such as "multiple groups," "multiple times," etc., unless otherwise specifically defined.

[0024] The method for preparing a metal-supported monolithic catalyst according to the present invention comprises the following steps:

[0025] Step 1: placing the carrier material in an alkaline solution or an acidic solution for ultrasonic cleaning;

[0026] Step 2: drying the ultrasonically cleaned support material at room temperature;

[0027] Step 3: placing the dried support material in a heating device and heating the heating device to a first heating temperature to form an oxide layer on the surface of the support material; after reaching the first heating temperature, the support material is heated for 1 to 2 hours;

[0028] Step 4: Continue heating the metal support with an oxide layer formed on the surface to a second heating temperature, and continue heating the support material for 2 to 4 hours after reaching the second heating temperature;

[0029] Step 5: After the continuous heating of the support material is completed, the support material is gradually cooled to room temperature and cooled to obtain a metal support;

[0030] Step 6: Use impregnation, 3D printing coating or arc spraying to load the catalytic layer on the metal carrier to obtain a monolithic catalyst based on the metal carrier.

[0031] In step 1, the carrier material is any one of 400 series stainless steel, 300 series stainless steel, iron-chromium alloy, iron-chromium-aluminum alloy, nickel, titanium, aluminum zirconate, aluminum titanate, aluminum phosphate, cordierite, rutile column or corundum or a combination thereof; the carrier material is in the form of any one of wire mesh, foam, fiber, fiber felt, round tube, and disc.

[0032] When the carrier material is placed in an alkaline solution, the alkaline solution is any one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate, the alkaline solution has a concentration range of 0.001 to 1 mol / L, and the ratio of the carrier material to the alkaline solution is 0.001 to 1 g / mL. When ultrasonically cleaning the carrier material, the alkaline solution containing the carrier material is set at a temperature range of 30 to 100° C. and ultrasonically cleaned for 0.1 to 5 hours to remove metal oxide layers, oil stains, or impurities on the surface of the carrier material and form a microscopic rough structure. The carrier surface is cleaned and activated, providing ideal operating interface conditions for subsequent processes.

[0033] When the carrier material is placed in an acidic solution, the acidic solution is any one or more of dilute sulfuric acid, dilute nitric acid, oxalic acid, and phosphoric acid, the concentration of the acidic solution ranges from 0.001 to 1 mol / L, and the amount ratio of the carrier material to the alkaline solution ranges from 0.001 to 1 g / mL; when ultrasonically cleaning the carrier material, the alkaline solution containing the carrier material is set at a temperature range of 30 to 100° C. and ultrasonically cleaned for 0.1 to 5 hours to remove the metal oxide layer, oil stains, or impurities on the surface of the carrier material and form a microscopic rough structure; so that the carrier surface is clean and activated, providing ideal operating interface conditions for subsequent processes.

[0034] In step 2, after completing ultrasonic cleaning of the carrier material, the cleaned carrier material is taken out from the solution and placed at room temperature for drying.

[0035] In step three, the carrier material dried in step two is placed in a heating device filled with a protective gas, such as nitrogen, for preliminary oxidation. Specifically, the temperature in the heating device is gradually increased from room temperature to 500-700°C at a heating rate of 2-10°C / min; then, the temperature is maintained at 500-700°C for 1-2 hours to pre-oxidize the dried carrier material and preliminarily form an oxide layer on the surface of the carrier material; then, in step four, the protective gas composition inside the heating device is changed, the gas inside the heating device is switched from nitrogen to air, and the temperature inside the heating device is continued to be heated to 950-1050°C at a rate of 2-5°C / min; then, the temperature is maintained at 950-1050°C for 2-4 hours to adjust the thickness of the oxide layer preliminarily formed on the surface of the carrier material in step three and densify the oxide layer preliminarily formed in step three.

[0036] In step five, after completing the continuous heating of the carrier material and densifying the oxide layer on the metal carrier, the heating temperature is gradually cooled to 500-600°C at a cooling rate of 1-2°C / min; after reaching 500-600°C, the temperature is gradually cooled to room temperature to avoid cracking of the oxide layer caused by thermal stress, and finally a metal carrier with a densified oxide layer on the surface and a high specific surface area is obtained; through the gradient oxidation treatment steps in steps three to five, the formed oxide layer presents the structural characteristics of columnar crystals growing perpendicular to the matrix, which not only retains the high strength and thermal conductivity of the metal carrier, but also enhances the surface roughness and chemical activity through the nanostructure regulation of the gradient oxide layer, providing ideal interface anchoring conditions for the subsequent coating of the catalyst slurry.

[0037] In step six, the catalytic layer is loaded on the metal support containing the densified oxide layer by impregnation, 3D printing coating or arc spraying to obtain a metal-coated catalyst;

[0038] When the catalytic layer is loaded on the metal support containing the densified oxide layer by the impregnation method; first, an active metal precursor solution containing an active metal is selected, specifically, the active metal is ruthenium element, and the active metal precursor solution is any one or more of ruthenium nitrate, ruthenium chloride, ruthenium acetate, chlororuthenic acid, ammonium chlororuthenate, sodium chlororuthenate or potassium chlororuthenate; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the treated metal support containing the densified oxide layer is impregnated with the mixed solution of tartaric acid and the active metal precursor solution at room temperature at equal volumes, and then, With the assistance of tartaric acid, the active metal is loaded on the metal carrier to obtain a catalyst precursor; the obtained catalyst precursor is then dried at a temperature of 30 to 80° C. for 2 to 12 hours; the catalyst precursor obtained after equal volume impregnation is calcined in an oxygen-containing atmosphere, the calcination temperature range is 200 to 600° C., and the calcination time is 0.5 to 24 hours; after the catalyst precursor is calcined, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature range is 200 to 600° C., and the reduction time is 0.5 to 24 hours, to obtain a monolithic catalyst based on a metal carrier.

[0039] When 3D printing is used to coat the catalyst layer on a metal support containing a densified oxide layer, a ruthenium precursor is first dissolved in a tartaric acid-assisted solution, where the active metal precursor solution is any one or more of ruthenium nitrate, ruthenium chloride, ruthenium acetate, chlororuthenic acid, ammonium chlororuthenate, sodium chlororuthenate, or potassium chlororuthenate; a binder is then added, where the binder is one or more of diaspore sol, aluminum colloid, or silica sol; the solution rheology is adjusted to prepare a 3D printing catalytic ink. Subsequently, a 3D direct ink writing technique is used to print the ruthenium-loaded layer layer by layer on the metal support through a nozzle (50 to 500 μm), controlling the printing rate to ensure uniform distribution of the catalyst; the molar ratio of tartaric acid to active metal is in the range of 0.5 to 15; and the mass of the active metal in the active metal precursor is 0.1 to 0.4 wt% of the mass of the calcined metal support.

[0040] The 3D-printed catalyst precursor is calcined in an oxygen-containing atmosphere at a temperature ranging from 200°C to 600°C for 0.5 to 24 hours. After calcination, the catalyst precursor is reduced in a hydrogen or hydrogen-nitrogen mixture atmosphere at a temperature ranging from 200°C to 600°C for 0.5 to 24 hours to produce a monolithic ammonia decomposition catalyst based on a metal support. This method achieves high-precision ruthenium loading, improving catalyst stability and activity.

[0041] When the catalytic layer is loaded on a metal support containing a densified oxide layer by using an arc spraying method, the treated metal support is placed in an arc spraying system, and an alloy wire or composite wire containing ruthenium elements is selected as the spraying material; the alloy wire or composite wire containing active metal includes any one or more of ruthenium-nickel alloy wire, ruthenium-aluminum alloy wire or ruthenium-aluminum oxide, or ruthenium-cerium oxide composite wire; the wire diameter ranges from 1 to 3 mm. Ruthenium layer deposition is carried out at an arc power of 2050kW and a spraying pressure of 0.2-0.8MPa, and the spraying temperature is controlled at 600-1200°C to form a uniform and dense ruthenium support layer layer by layer; the mass of the active metal in the active metal precursor is 0.1-0.4wt% of the mass of the metal support after calcination; the catalyst precursor obtained after spraying is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture at a reduction temperature range of 200-600°C and a reduction time of 0.5-24 hours to obtain a monolithic catalyst based on a metal support.

[0042] The preparation method of the metal-supported monolithic catalyst described in the present application is further described below with reference to the examples.

[0043] Example 1

[0044] Step 1: ultrasonically clean the iron-chromium alloy wire mesh in a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 0.001 mol / L and the ratio of the iron-chromium alloy wire mesh to the sodium hydroxide solution is 0.001 g / ml; ultrasonically clean the alkaline solution containing the iron-chromium alloy wire at a temperature of 30° C. for 0.1 hour;

[0045] Step 2: Drying the ultrasonically cleaned iron-chromium alloy wire mesh at room temperature;

[0046] Step 3: Place the dried iron-chromium alloy wire mesh in a heating device filled with nitrogen for preliminary oxidation. The temperature in the heating device is heated to 700°C at a heating rate of 2°C / min and maintained at 700°C for 1 hour. An oxide layer is formed on the surface of the iron-chromium alloy wire mesh.

[0047] Step 4: Replace the nitrogen in the heating device with air and continue heating to 1000°C at a heating rate of 1°C / min; and maintain the temperature at 1000°C for 2 hours to adjust the thickness of the oxide layer initially formed on the surface of the iron-chromium alloy wire mesh in step 3 and densify the oxide layer initially formed in step 3;

[0048] Step 5: Lower the temperature to 600°C at a cooling rate of 1°C / min, then cool it to room temperature and cool the iron-chromium alloy wire mesh;

[0049] Step six: The catalytic layer is loaded on the iron-chromium alloy wire mesh containing a densified oxide layer on the surface by an impregnation method: first, ruthenium nitrate is selected as the active metal precursor solution; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the treated iron-chromium alloy wire mesh containing a densified oxide layer is impregnated with an equal volume of the mixed solution consisting of tartaric acid and the active metal precursor solution at room temperature, and the active metal is loaded on the iron-chromium alloy wire mesh with the auxiliary action of tartaric acid to obtain a catalyst precursor; the obtained catalyst precursor is then dried at 30°C for 2 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere, wherein the calcination temperature is 400°C and the calcination time is 0.5 hour; after the calcination of the catalyst precursor is completed, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature is 300°C, and the reduction time is 0.5 hour to obtain an integral catalyst based on iron-chromium alloy.

[0050] Example 2

[0051] Step 1: ultrasonically clean the iron-chromium alloy wire mesh in a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 0.001 mol / L and the ratio of the iron-chromium alloy wire mesh to the sodium hydroxide solution is 0.001 g / ml; ultrasonically clean the alkaline solution containing the iron-chromium alloy wire at a temperature of 30° C. for 0.1 hour;

[0052] Step 2: Drying the ultrasonically cleaned iron-chromium alloy wire mesh at room temperature;

[0053] Step 3: Place the dried iron-chromium alloy wire mesh in a heating device filled with nitrogen for preliminary oxidation. The temperature in the heating device is heated to 500°C at a heating rate of 2°C / min and maintained at 500°C for 1 hour. An oxide layer is formed on the surface of the iron-chromium alloy wire mesh.

[0054] Step 4: Replace the nitrogen in the heating device with air and continue heating to 950°C at a heating rate of 1°C / min; and maintain the temperature at 950°C for 2 hours to adjust the thickness of the oxide layer initially formed on the surface of the iron-chromium alloy wire mesh in step 3 and densify the oxide layer initially formed in step 3;

[0055] Step 5: Lower the temperature to 600°C at a cooling rate of 1°C / min, then cool it to room temperature and cool the iron-chromium alloy wire mesh;

[0056] Step six: The catalytic layer is loaded on the iron-chromium alloy wire mesh containing a densified oxide layer on the surface by an impregnation method: first, ruthenium nitrate is selected as the active metal precursor solution; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the treated iron-chromium alloy wire mesh containing a densified oxide layer is impregnated with an equal volume of the mixed solution consisting of tartaric acid and the active metal precursor solution at room temperature, and the active metal is loaded on the iron-chromium alloy wire mesh with the auxiliary action of tartaric acid to obtain a catalyst precursor; the obtained catalyst precursor is then dried at 30°C for 2 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere, wherein the calcination temperature is 400°C and the calcination time is 0.5 hour; after the calcination of the catalyst precursor is completed, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature is 300°C, and the reduction time is 0.5 hour to obtain an integral catalyst based on iron-chromium alloy.

[0057] Example 3

[0058] Step 1: ultrasonically clean the iron-chromium alloy wire mesh in a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 0.001 mol / L and the ratio of the iron-chromium alloy wire mesh to the sodium hydroxide solution is 0.001 g / ml; ultrasonically clean the alkaline solution containing the iron-chromium alloy wire at a temperature of 30° C. for 0.1 hour;

[0059] Step 2: Drying the ultrasonically cleaned iron-chromium alloy wire mesh at room temperature;

[0060] Step 3: Place the dried iron-chromium alloy wire mesh in a heating device filled with nitrogen for preliminary oxidation. The temperature in the heating device is heated to 600°C at a heating rate of 2°C / min and maintained at 600°C for 1 hour. An oxide layer is formed on the surface of the iron-chromium alloy wire mesh.

[0061] Step 4: Replace the nitrogen in the heating device with air and continue heating to 1050°C at a heating rate of 1°C / min; and maintain the temperature at 1050°C for 2 hours to adjust the thickness of the oxide layer initially formed on the surface of the iron-chromium alloy wire mesh in step 3 and densify the oxide layer initially formed in step 3;

[0062] Step 5: Lower the temperature to 600°C at a cooling rate of 1°C / min, then cool it to room temperature and cool the iron-chromium alloy wire mesh;

[0063] Step six: The catalytic layer is loaded on the iron-chromium alloy wire mesh containing a densified oxide layer on the surface by an impregnation method: first, ruthenium nitrate is selected as the active metal precursor solution; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the treated iron-chromium alloy wire mesh containing a densified oxide layer is impregnated with an equal volume of the mixed solution consisting of tartaric acid and the active metal precursor solution at room temperature, and the active metal is loaded on the iron-chromium alloy wire mesh with the auxiliary action of tartaric acid to obtain a catalyst precursor; the obtained catalyst precursor is then dried at 30°C for 2 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere, wherein the calcination temperature is 400°C and the calcination time is 0.5 hour; after the calcination of the catalyst precursor is completed, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature is 300°C, and the reduction time is 0.5 hour to obtain an integral catalyst based on iron-chromium alloy.

[0064] Example 4

[0065] Step 1: placing the iron-chromium-aluminum fiber felt in a nitric acid solution for ultrasonic cleaning, wherein the concentration range of the nitric acid solution is 0.001 mol / L, and the amount ratio of the iron-chromium-aluminum fiber felt to the nitric acid solution is 0.001 g / ml; setting the acidic solution containing the iron-chromium-aluminum fiber felt at a temperature range of 30° C. for ultrasonic cleaning for 0.1 hour;

[0066] Step 2: drying the ultrasonically cleaned iron-chromium-aluminum fiber felt at room temperature;

[0067] Step 3: placing the dried iron-chromium-aluminum fiber felt in a heating device filled with nitrogen for preliminary oxidation, heating the temperature in the heating device to 700° C. at a heating rate of 2° C. / min; and maintaining the temperature at 700° C. for 1 hour; forming an oxide layer on the surface of the iron-chromium-aluminum fiber felt;

[0068] Step 4: Replace the nitrogen in the heating device with air, continue heating to 1000°C at a heating rate of 1°C / min, and maintain the temperature at 1000°C for 2 hours to adjust the thickness of the oxide layer initially formed on the surface of the iron-chromium-aluminum fiber felt in step 3 and densify the oxide layer initially formed in step 3;

[0069] Step 5: lowering the temperature to 600°C at a cooling rate of 1°C / min, then cooling to room temperature and cooling the iron-chromium-aluminum fiber felt;

[0070] Step six: The catalytic layer is loaded on the iron-chromium-aluminum fiber felt containing a densified oxide layer on the surface by an impregnation method: first, ruthenium nitrate is selected as the active metal precursor solution; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the treated iron-chromium-aluminum fiber felt containing a densified oxide layer is impregnated with an equal volume of the mixed solution consisting of tartaric acid and the active metal precursor solution at room temperature, and the active metal is loaded on the iron-chromium-aluminum fiber felt with the assistance of tartaric acid to obtain a catalyst precursor; the obtained catalyst precursor is then dried at 30°C for 2 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere, wherein the calcination temperature is 400°C and the calcination time is 0.5 hour; after the calcination of the catalyst precursor is completed, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature is 300°C, and the reduction time is 0.5 hour to obtain an iron-chromium-aluminum-based integral catalyst.

[0071] Example 5

[0072] Step 1: ultrasonically clean the iron-chromium alloy wire mesh in a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 0.001 mol / L and the ratio of the iron-chromium alloy wire mesh to the sodium hydroxide solution is 0.001 g / ml; ultrasonically clean the alkaline solution containing the iron-chromium alloy wire mesh at a temperature of 30° C. for 0.1 hour;

[0073] Step 2: Drying the ultrasonically cleaned iron-chromium alloy wire mesh at room temperature;

[0074] Step 3: Place the dried iron-chromium alloy wire mesh in a heating device filled with nitrogen for preliminary oxidation. The temperature in the heating device is heated to 700°C at a heating rate of 2°C / min and maintained at 700°C for 1 hour. An oxide layer is formed on the surface of the iron-chromium alloy wire mesh.

[0075] Step 4: Replace the nitrogen in the heating device with air and continue heating to 1000°C at a heating rate of 1°C / min; and maintain the temperature at 1000°C for 2 hours to adjust the thickness of the oxide layer initially formed on the surface of the iron-chromium alloy wire mesh in step 3 and densify the oxide layer initially formed in step 3;

[0076] Step 5: Lower the temperature to 600°C at a cooling rate of 1°C / min, then cool it to room temperature and cool the iron-chromium alloy wire mesh;

[0077] Step 6: Use 3D printing coating to load the catalytic layer on the iron-chromium alloy wire mesh with a densified oxide layer on the surface: first dissolve the ruthenium precursor in the tartaric acid auxiliary solution, the active metal precursor solution is any one or more of ruthenium nitrate, ruthenium chloride, ruthenium acetate, chlororuthenic acid, ammonium chlororuthenate, sodium chlororuthenate or potassium chlororuthenate; then add a binder, the binder is one or more of diaspore sol, aluminum colloid, and silica sol; adjust the solution rheology to prepare 3D printing catalytic ink. Subsequently, using 3D direct ink writing technology, print the ruthenium load layer layer by layer on the metal support through a nozzle (50μm), control the printing rate to ensure uniform distribution of the catalyst; wherein the molar ratio of tartaric acid to active metal is in the range of 0.5; the mass of the active metal in the active metal precursor is 0.1wt% of the mass of the calcined iron-chromium-aluminum metal support; obtain an integrated catalyst based on iron-chromium alloy.

[0078] Example 6

[0079] Step 1: ultrasonically clean the iron-chromium alloy wire mesh in a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 0.001 mol / L and the ratio of the iron-chromium alloy wire mesh to the sodium hydroxide solution is 0.001 g / ml; ultrasonically clean the alkaline solution containing the iron-chromium alloy wire mesh at a temperature of 30° C. for 0.1 hour;

[0080] Step 2: Drying the ultrasonically cleaned iron-chromium alloy wire mesh at room temperature;

[0081] Step 3: Place the dried iron-chromium alloy wire mesh in a heating device filled with nitrogen for preliminary oxidation. The temperature in the heating device is heated to 700°C at a heating rate of 2°C / min and maintained at 700°C for 1 hour. An oxide layer is formed on the surface of the iron-chromium alloy wire mesh.

[0082] Step 4: Replace the nitrogen in the heating device with air and continue heating to 1000°C at a heating rate of 1°C / min; and maintain the temperature at 1000°C for 2 hours to adjust the thickness of the oxide layer initially formed on the surface of the iron-chromium alloy wire mesh in step 3 and densify the oxide layer initially formed in step 3;

[0083] Step 5: Lower the temperature to 600°C at a cooling rate of 1°C / min, then cool it to room temperature and cool the iron-chromium alloy wire mesh;

[0084] Step 6: Use arc spraying to load the catalytic layer on the iron-chromium alloy wire mesh with a densified oxide layer on the surface, place the treated iron-chromium alloy wire mesh in the arc spraying system, and select an alloy wire containing ruthenium as the spraying material; the alloy wire containing active metal is ruthenium-nickel alloy wire; the wire diameter is 1mm; the ruthenium layer is deposited at an arc power of 2050kW and a spraying pressure of 0.2MPa, and the spraying temperature is controlled at 600°C to form a uniform and dense ruthenium load layer layer by layer; the mass of the active metal in the active metal precursor is 0.1wt% of the mass of the calcined iron-chromium alloy wire mesh; the catalyst precursor obtained after spraying is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature range is 200°C, and the reduction time is 0.5 hour to obtain an integrated catalyst based on iron-chromium alloy.

[0085] Comparative Example 1

[0086] Step 1: ultrasonically clean the iron-chromium alloy fiber in a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 1 mol / L and the ratio of the iron-chromium alloy fiber to the sodium hydroxide solution is 1 g / ml; ultrasonically clean the alkaline solution containing the carrier material at a temperature of 100° C. for 5 hours;

[0087] Step 2: Dry the iron-chromium alloy fiber after ultrasonic cleaning at room temperature; after drying, calcine the metal carrier in an environment of 600° C. for 2 hours;

[0088] Step 3: Lowering the temperature to 600°C at a cooling rate of 1°C / min, and then cooling to room temperature to obtain a metal support;

[0089] Step 4: The catalytic layer is loaded on the iron-chromium alloy fiber by the impregnation method: first, ruthenium nitrate is selected as the active metal precursor solution; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the iron-chromium alloy fiber treated with a densified oxide layer is impregnated with an equal volume of the mixed solution consisting of tartaric acid and the active metal precursor solution at room temperature, and the active metal is loaded on the iron-chromium alloy fiber with the assistance of tartaric acid to obtain a catalyst precursor; the obtained catalyst precursor is then dried at 30°C for 2 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere, wherein the calcination temperature is 400°C and the calcination time is 0.5 hour; after the calcination of the catalyst precursor is completed, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature is 300°C, and the reduction time is 0.5 hour to obtain an integral catalyst based on iron-chromium alloy.

[0090] Comparative Example 2

[0091] Step 1: Place the iron-chromium alloy wire mesh in deionized water for ultrasonic cleaning at 30°C for 30 minutes;

[0092] Step 2: Drying the ultrasonically cleaned iron-chromium alloy wire mesh at room temperature;

[0093] Step 3: Place the dried iron-chromium alloy wire mesh in a heating device filled with nitrogen for preliminary oxidation. The temperature in the heating device is heated to 700°C at a heating rate of 2°C / min and maintained at 700°C for 1 hour.

[0094] Step 4: Lower the temperature to 600°C at a cooling rate of 1°C / min, then cool it to room temperature and cool the iron-chromium alloy wire mesh;

[0095] Step 5: The catalytic layer is loaded on the iron-chromium alloy wire mesh by the impregnation method: first, ruthenium nitrate is selected as the active metal precursor solution; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the iron-chromium alloy wire mesh treated with a densified oxide layer and the mixed solution consisting of tartaric acid and the active metal precursor solution are impregnated in equal volumes at room temperature, and the active metal is loaded on the iron-chromium alloy wire mesh with the auxiliary action of tartaric acid to obtain a catalyst precursor; the obtained catalyst precursor is then dried at 30°C for 2 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere, wherein the calcination temperature is 400°C and the calcination time is 0.5 hour; after the calcination of the catalyst precursor is completed, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature is 300°C, and the reduction time is 0.5 hour to obtain an integral catalyst based on iron-chromium alloy.

[0096] Comparative Example 3

[0097] Step 1: Place the iron-chromium-aluminum metal carrier in a sandblasting device, select 100-300 μm Al2O3 or SiC particles as the sandblasting medium, adjust the spray pressure to 0.3-0.8 MPa, and evenly treat the surface of the metal carrier at a spray angle of 30°-45°. The sandblasting time is 20-120 seconds. Use high-pressure dry air to blow away residual abrasives, then ultrasonically clean in deionized water, and then dry at 120°C.

[0098] Step 2: After drying, the iron-chromium-aluminum metal is calcined in an air atmosphere at 1000°C for 4 hours;

[0099] Step 3: Lower the temperature to 600°C at a cooling rate of 2°C / min, then cool to room temperature and cool the iron-chromium-aluminum metal;

[0100] Step 4: The catalytic layer is loaded on the metal support by the impregnation method: first, ruthenium nitrate is selected as the active metal precursor solution; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the treated metal support containing a densified oxide layer is impregnated with an equal volume of the mixed solution consisting of tartaric acid and the active metal precursor solution at room temperature, and the active metal is loaded on the metal support with the assistance of tartaric acid to obtain a catalyst precursor; the obtained catalyst precursor is then dried at 30°C for 2 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere, wherein the calcination temperature is 400°C and the calcination time is 0.5 hour; after the calcination of the catalyst precursor is completed, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature is 300°C, and the reduction time is 0.5 hour to obtain an integral catalyst based on a metal support.

[0101] The specific surface area, active component loading of the monolithic catalyst precursor materials prepared in Examples 1 to 6 and Comparative Examples 1 to 3, and ammonia conversion were tested at 600 to 1000° C. The following are the test results:

[0102]

[0103] By combining alkaline etching with gradient oxidation to treat the metal support, the ammonia decomposition performance is effectively improved, especially under high temperature conditions, the reaction efficiency of the catalyst is significantly improved; among them, alkaline etching is used to remove oxides, dirt or other impurities on the surface of the iron, chromium and aluminum metal support, providing a cleaner surface; gradient oxidation is a step carried out after alkaline etching. By controlling the degree and depth of oxidation, different oxide layers are formed on the surface of the metal support, enhancing the coupling between the metal support and the catalyst. The properties of this oxide layer (such as porosity, crystal structure, etc.) contribute to the dispersion of the catalyst and the stability of the active sites; the catalyst layer is strongly bonded to the metal support, thereby enhancing the thermal stability of the interface, optimizing the mass transfer / heat transfer performance, and reducing the process complexity. It is suitable for large-scale applications and has excellent ammonia decomposition and hydrogen production performance and stability.

[0104] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a monolithic catalyst based on a metal carrier, characterized in that: The following steps are involved: Step 1: placing the carrier material in an alkaline solution or an acidic solution for ultrasonic cleaning; Step 2: drying the ultrasonically cleaned support material at room temperature; Step 3: placing the dried support material in a heating device and heating the heating device to a first heating temperature to form an oxide layer on the surface of the support material; after reaching the first heating temperature, the support material is heated for 1 to 2 hours; Step 4: Continue heating the support material with the oxide layer formed on the surface to a second heating temperature, and maintain heating the support material for 2 to 4 hours after reaching the second heating temperature; Step 5: After the carrier material is continuously heated, it is gradually cooled to room temperature to obtain a metal carrier; Step 6: Use impregnation, 3D printing coating or arc spraying to load the catalytic layer on the metal carrier to obtain a monolithic catalyst based on the metal carrier.

2. The method for preparing a metal-supported monolithic catalyst according to claim 1, wherein: In step 1, the carrier material is any one of stainless steel, iron-chromium alloy, iron-chromium-aluminum alloy, nickel, titanium, aluminum zirconate, aluminum titanate, aluminum phosphate, cordierite, rutile column or corundum or a combination thereof; the carrier material is in the form of any one of wire mesh, foam, fiber, fiber felt, round tube and disc.

3. The method for preparing a metal-supported monolithic catalyst according to claim 2, wherein: When the carrier material is placed in an alkaline solution, the alkaline solution is any one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate, the concentration of the alkaline solution is in the range of 0.001 to 1 mol / L, and the ratio of the carrier material to the alkaline solution is in the range of 0.001 to 1 g / mL; when ultrasonically cleaning the carrier material, the alkaline solution containing the carrier material is set at a temperature range of 30 to 100° C. and ultrasonically cleaned for 0.1 to 5 hours; When the carrier material is placed in an acidic solution, the acidic solution is any one or more of dilute sulfuric acid, dilute nitric acid, oxalic acid, and phosphoric acid, the concentration range of the acidic solution is 0.001 to 1 mol / L, and the usage ratio of the carrier material to the acidic solution is 0.001 to 1 g / mL; when ultrasonically cleaning the carrier material, the acidic solution containing the carrier material is set at a temperature range of 30 to 100° C. and ultrasonically cleaned for 0.1 to 5 hours.

4. The method for preparing a metal-supported monolithic catalyst according to claim 1, wherein: In step three, the heating device is filled with a protective gas, which is nitrogen; the temperature in the heating device is increased to a first heating temperature at a heating rate of 2 to 10°C / min, which is 500 to 700°C; the heating device is maintained at a temperature of 500 to 700°C for 1 to 2 hours.

5. The method for preparing a metal-supported monolithic catalyst according to claim 4, wherein: In step 4, the heating device is filled with air, and the temperature inside the heating device is continuously heated to a second heating temperature at a rate of 2 to 5°C / min, and the second heating temperature is 950 to 1050°C; the heating device is maintained at a temperature of 950 to 1050°C for 2 to 4 hours.

6. The method for preparing a metal-supported monolithic catalyst according to claim 1, wherein: In step five, the temperature is first cooled to 500-600° C. at a cooling rate of 1-2° C. / min; and then cooled to room temperature to obtain a metal support.

7. The method for preparing a metal-supported monolithic catalyst according to claim 1, wherein: In step six, when the catalytic layer is loaded on the metal support containing the densified oxide layer by an impregnation method; First, an active metal precursor solution containing an active metal is selected, wherein the active metal is ruthenium element, and the active metal precursor solution is any one or more of ruthenium nitrate, ruthenium chloride, ruthenium acetate, chlororuthenic acid, ammonium chlororuthenate, sodium chlororuthenate or potassium chlororuthenate; then, tartaric acid is dissolved in the active metal precursor solution to form a mixed solution of tartaric acid and the active metal precursor solution; then, the metal support having a densified oxide layer is treated and the mixed solution of tartaric acid and the active metal precursor solution is subjected to isotropic treatment at room temperature. The catalyst precursor is dried at a temperature of 30 to 80° C. for 2 to 12 hours; the catalyst precursor obtained after the equal volume impregnation is calcined in an oxygen-containing atmosphere at a calcination temperature range of 200 to 600° C. for 0.5 to 24 hours; after the catalyst precursor is calcined, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture at a reduction temperature range of 200 to 600° C. for 0.5 to 24 hours; When the catalytic layer is loaded on a metal support containing a densified oxide layer by 3D printing coating, the ruthenium precursor is first dissolved in a tartaric acid auxiliary solution, and the active metal precursor solution is any one or more of ruthenium nitrate, ruthenium chloride, ruthenium acetate, chlororuthenic acid, ammonium chlororuthenate, sodium chlororuthenate or potassium chlororuthenate; then a binder is added, and the binder is one or more of diaspore sol, aluminum colloid, and silica sol; the rheological properties of the solution are adjusted to prepare a 3D printing catalytic ink; the ruthenium loading layer is printed layer by layer on the metal support through a nozzle; the tartaric acid and the active metal precursor solution are reacted with each other. The molar ratio range is 0.5 to 15; the mass of the active metal in the active metal precursor is 0.1 to 0.4 wt% of the mass of the metal support after calcination; the obtained catalyst precursor is calcined in an oxygen-containing atmosphere at a calcination temperature range of 200 to 600° C. and a calcination time of 0.5 to 24 hours; after the catalyst precursor is calcined, the calcined catalyst precursor is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture at a reduction temperature range of 200 to 600° C. and a reduction time of 0.5 to 24 hours; When the catalytic layer is loaded on a metal support containing a densified oxide layer by an arc spraying method, the treated metal support is placed in an arc spraying system, and an alloy wire or composite wire containing ruthenium is selected as the spraying material; the alloy wire or composite wire containing active metal includes any one or more of ruthenium-nickel alloy wire, ruthenium-aluminum alloy wire or ruthenium-aluminum oxide, or ruthenium-cerium oxide composite wire; the wire diameter ranges from 1 to 3 mm; the ruthenium layer is deposited at an arc power of 2050 kW and a spraying pressure of 0.2 to 0.8 MPa, the spraying temperature is controlled at 600 to 1200° C., and a uniform and dense ruthenium loading layer is formed layer by layer; the mass of the active metal in the active metal precursor is 0.1 to 0.4 wt% of the mass of the calcined metal support; the catalyst precursor obtained after spraying is reduced in an atmosphere of hydrogen or a hydrogen-nitrogen mixture, the reduction temperature ranges from 200 to 600° C., and the reduction time is 0.5 to 24 hours.

8. A monolithic catalyst based on a metal support, characterized in that: The catalyst is prepared by the method for preparing a metal-supported integral catalyst according to any one of claims 1 to 8.

9. Use of a metal-supported monolithic catalyst prepared by the method for preparing a metal-supported monolithic catalyst according to any one of claims 1 to 7, characterized in that: The metal-supported integral catalyst is applied to the decomposition of ammonia to produce hydrogen.

Images