Ammonia decomposition hydrogen purification composite membrane based on high-temperature stable surface catalytic material and preparation method

Abstract

The application discloses a kind of based on high-temperature stability surface catalytic material's ammonia decomposition hydrogen purification composite membrane and preparation method, the composite membrane includes matrix layer, and catalytic layer is distributed in the surface of matrix layer two sides, the matrix layer is vanadium metal layer, the catalytic layer is vanadium nitride layer.The composite membrane of the application has excellent hydrogen permeation performance and high-temperature durability, and vanadium nitride has the catalytic performance of hydrogen dissociation and hydrogen polymerization comparable with palladium under ammonia decomposition hydrogen production condition, and mutual diffusion does not occur with matrix layer at high temperature above 450 DEG C.In addition, the application is carried out structure regulation on the surface of vanadium metal layer, and the thickness of vanadium nitride catalytic layer can be conveniently grown in situ in matrix, and it is more suitable for large-scale industrial production.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of hydrogen separation and purification, in particular to an ammonia decomposition hydrogen purification composite membrane based on a high-temperature stability surface catalytic material and a preparation method. BACKGROUND

[0002] High-purity hydrogen is widely used in national defense and civil fields and has important application value. The preparation of high-purity hydrogen includes industrial hydrogen production and hydrogen purification. For example, hydrogen produced by the ammonia decomposition method contains a large amount of impurity gases (such as ammonia and nitrogen), and needs to be purified to obtain high-purity hydrogen. The membrane separation method has the advantages of energy saving, environmental protection and low price, and has been widely used in industry. The noble metal palladium (Pd) and its alloys are currently the main hydrogen separation membrane materials used in industry. However, Pd is scarce and expensive, and it is urgent to develop new Pd-free hydrogen separation membrane materials. Group 5 metal vanadium (V) and its alloys have higher hydrogen permeation performance than Pd and significantly lower prices, and are currently a new type of hydrogen separation membrane material that has attracted much attention. Because the catalytic ability of V and its alloys on the surface is weak, a nano-thickness Pd is usually plated on the surface as a catalytic layer to promote hydrogen molecule dissociation and hydrogen atom polymerization. The composite membrane formed in this way realizes hydrogen separation and purification through hydrogen catalysis of the surface Pd and hydrogen dissolution, diffusion and permeation of the matrix. However, when the temperature exceeds 450 DEG C, the surface Pd and the matrix will undergo interfacial interdiffusion, resulting in Pd membrane catalytic failure and severe decline in the hydrogen permeation performance of the composite membrane. SUMMARY

[0003] In view of the deficiencies of the prior art, the application provides an ammonia decomposition hydrogen purification composite membrane based on a high-temperature stability surface catalytic material and a preparation method. The composite membrane has excellent hydrogen permeation performance and high-temperature durability, and will not undergo interdiffusion with the matrix layer at a high temperature of 450 DEG C or above.

[0004] The application adopts the following technical scheme:

[0005] An ammonia decomposition hydrogen purification composite membrane comprises a matrix layer and catalytic layers distributed on both sides of the matrix layer, the matrix layer is a vanadium metal layer, and the catalytic layers are vanadium nitride layers.

[0006] The chemical formula of the vanadium nitride is VNx (0.2<=x<=1).

[0007] The matrix layer material is one of pure V, a V-Ni alloy, a V-Cr alloy, a V-Cu alloy, a V-Fe alloy, a V-Al alloy, a V-Co alloy, a V-Mo alloy, a V-W alloy, a V-Pd alloy, a V-Ti-Ni alloy, a V-Fe-Al alloy, a V-Mo-W alloy, a V-Cu-Al alloy, a V-Co-Al alloy, a V-Ni-Al alloy and a vanadium-based high-entropy alloy.

[0008] The thickness of the substrate layer is 10-500 μm, and the diameter is 0.5 cm-100 cm; the thickness of the catalytic layer is 2-500 nm, and the diameter is consistent with that of the substrate layer.

[0009] Preferably, the thickness of the substrate layer is 25-250 μm, and the diameter is 1 cm-50 cm; the thickness of the catalytic layer is 20-300 nm, and the diameter is consistent with that of the substrate layer.

[0010] A method for preparing a composite membrane for purifying hydrogen by decomposing ammonia, wherein a catalytic layer is prepared on both sides of the substrate layer by one of the following processes: magnetron sputtering, ion beam sputtering, evaporation plating, pulse deposition, molecular beam epitaxy, atomic layer deposition and ion implantation.

[0011] Preferably, a vanadium nitride layer is prepared on both sides of the substrate layer by ion implantation.

[0012] The ion implantation process comprises the following steps:

[0013] S1. Ion cleaning is performed on both sides of the substrate vanadium metal layer by argon plasma to complete surface treatment of the vanadium metal layer;

[0014] S2. Nitrogen ions are implanted on both sides of the treated vanadium metal layer to form vanadium nitride, thereby obtaining a vanadium nitride / vanadium metal / vanadium nitride "sandwich" structure layer;

[0015] S3. The structure layer prepared in step S2 is annealed to improve the uniformity and stability of the vanadium nitride structure and eliminate structural defects, thereby obtaining the desired composite membrane.

[0016] In step S1, the vacuum degree in the argon ion beam cleaning chamber is less than 10 -4 Pa, the argon gas flow is 5-20 sccm, the working pressure is 0.02-0.08 Pa, the beam current density is 10-20 mA / cm 2 , the argon ion energy is 400-1000 eV, and the cleaning time is 20-40 min;

[0017] In step S2, nitrogen gas is introduced into the reaction chamber, and N plasma implantation is achieved by an N ion implanter. The chamber vacuum degree is 2×10 -3 -1×10 -5 Pa, the nitrogen ion implantation energy is 30-80 keV, the implantation temperature is 25-500℃, the implantation dose is 1×10 15 ions / cm 2 -9.9×10 17 ions / cm 2By controlling different nitrogen injection doses, the composition of the vanadium nitride can be regulated.

[0018] In the step S3, the structure layer sample is placed into a heat treatment furnace for annealing treatment, and the annealing temperature is 500-900 DEG C under helium atmosphere, and the annealing time is 0.5-12h, and different annealing processes are controlled to regulate the thickness of the vanadium nitride layer.

[0019] Before ion implantation, the preparation process S0 of the substrate vanadium metal layer is further included, comprising the following steps:

[0020] S0-1, smelting: high-purity dendritic vanadium particles are melted into vanadium liquid by using a large-capacity regenerative smelting furnace, and the vanadium liquid is introduced into a casting mill through a flow guide groove, a refiner is added in the process, and the processes of degassing and deslagging are completed;

[0021] S0-2, rolling: the vanadium liquid after smelting in step S0-1 is introduced into a casting mill to cast a blank, and the blank is continuously cold-rolled until the thickness requirement is met, and different degrees of homogenizing annealing are performed during the process;

[0022] S0-3, cleaning: the rolled vanadium foil is sequentially cleaned by ultrasonic cleaning with acetone, anhydrous ethanol and deionized water for 5-10min, and then dried, thereby obtaining the required substrate vanadium metal layer.

[0023] The application of an ammonia decomposition hydrogen purification composite membrane in continuously and stably separating and purifying hydrogen from ammonia decomposition mixed gas.

[0024] The technical scheme of the present application has the following advantages:

[0025] A、The vanadium nitride catalytic layer in the present application has excellent ability to catalyze the dissociation of hydrogen molecules and the polymerization of hydrogen atoms, and can provide a lower surface restriction when hydrogen permeation at a high temperature of 450 DEG C or above, thereby improving the hydrogen permeation performance of the composite membrane.

[0026] B、The vanadium nitride catalytic layer in the present application is structurally stable and does not fear interdiffusion with the substrate vanadium metal layer at high temperatures, thereby improving the hydrogen permeation stability of the composite membrane; at the same time, the vanadium nitride catalytic layer can inhibit the combination of nitrogen and hydrogen, and weaken the reverse reaction process of ammonia decomposition.

[0027] C、The present application regulates the structure on the surface of the vanadium metal layer, facilitates in-situ growth of a thickness-controllable vanadium nitride catalytic layer on the substrate, and is more suitable for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present application, the drawings needed to be used in the specific embodiments will be briefly introduced as follows. Obviously, the drawings described in the following description are some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without any creative work based on these drawings also belong to the protection scope of the present application.

[0029] Figure 1 The preparation process schematic diagram of the hydrogen purification composite membrane by ammonia decomposition in Example 1;

[0030] Figure 2 The picture of the VN / V / VN hydrogen separation composite membrane prepared in Example 1;

[0031] Figure 3 The XRD diagram of VN in Example 2;

[0032] Figure 4 The polarization curve of the hydrogen evolution of VN in Examples 1-2;

[0033] Figure 5 The curve of the relationship between the hydrogen permeation coefficient Ф and the temperature T of the VN / V / VN composite membrane in Examples 1-2;

[0034] Figure 6 The high-temperature sustained hydrogen permeation test curve of the VN / V / VN composite membrane in Example 2. Specific embodiments

[0035] The technical solutions of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative work belong to the protection scope of the present application.

[0036] The application provides an ammonia decomposition hydrogen purification composite membrane, which comprises a substrate layer and a catalytic layer distributed on both sides of the substrate layer, the substrate layer is a vanadium metal layer, and the substrate layer material can be selected from one of pure V, V-Ni alloy, V-Cr alloy, V-Cu alloy, V-Fe alloy, V-Al alloy, V-Co alloy, V-Mo alloy, V-W alloy, V-Pd alloy, V-Ti-Ni alloy, V-Fe-Al alloy, V-Mo-W alloy, V-Cu-Al alloy, V-Co-Al alloy, V-Ni-Al alloy and vanadium-based high-entropy alloy; and the catalytic layer is a vanadium nitride layer, and the chemical formula of the vanadium nitride is VNx (0.2≤x≤1). The transition metal nitride vanadium nitride (VN) has similar electronic structure and catalytic properties to Pt group metals, is structurally stable, and will not interdiffuse with the metal substrate at high temperatures, and is an excellent V surface hydrogen catalytic material. In the ammonia decomposition hydrogen purification process, first, hydrogen molecules are dissociated into hydrogen atoms on the VN surface, and under high temperature and high pressure conditions, the hydrogen atoms diffuse in the interstitial positions of the vanadium metal layer, and then the hydrogen atoms polymerize into hydrogen molecules on the VN surface on the other side and are desorbed, completing the hydrogen permeation process. Since VN only has selective permeability to hydrogen, other impurity gases cannot pass through, thereby completing the separation and purification of hydrogen.

[0037] Further, the thickness of the substrate layer is 10-500 μm, preferably 25-250 μm, and the diameter is 0.5 cm-100 cm, preferably 1 cm-50 cm; the thickness of the catalytic layer is 2-500 nm, preferably 20-300 nm, and the diameter is consistent with the diameter of the substrate layer.

[0038] The ammonia decomposition hydrogen purification composite membrane can be prepared by one of the following processes: magnetron sputtering, ion beam sputtering, evaporation plating, pulse deposition, molecular beam epitaxy, atomic layer deposition and ion implantation on both sides of the substrate layer to prepare the catalytic layer. Preferably, the vanadium nitride layer is prepared by ion implantation on both sides of the substrate layer, and the preparation process specifically comprises the following steps:

[0039] S1. The double-sided surface of the substrate vanadium metal layer is subjected to ion cleaning by argon plasma to complete the surface treatment of the vanadium metal layer;

[0040] S2. Nitrogen ions are implanted on the double-sided surface of the treated vanadium metal layer to form vanadium nitride, and a vanadium nitride / vanadium metal / vanadium nitride "sandwich" structure layer is obtained;

[0041] S3. The structure layer prepared in step S2 is subjected to annealing treatment to improve the uniformity and structural stability of the vanadium nitride, and eliminate the defects in the structure, so that the required composite membrane is obtained.

[0042] The process parameters in the preparation process are as follows:

[0043] In step S1, the vacuum degree in the argon ion beam cleaning chamber is less than 10-4 Pa, argon flow rate 5–20 sccm, working pressure 0.02–0.08 Pa, beam density 10–20 mA / cm² 2 Argon ion energy is 400–1000 eV, and cleaning time is 20–40 min;

[0044] In step S2, nitrogen gas is introduced into the reaction chamber, and N plasma is injected using an N ion implanter, achieving a chamber vacuum of 2 × 10⁻⁶. -3 ~1×10 -5 Pa, nitrogen ion implantation energy is 30–80 keV, implantation temperature is 25–500℃, and implantation dose is 1×10⁻⁶. 15 ions / cm2~9.9×10 17 ions / cm 2 The composition of vanadium nitride can be controlled by adjusting different nitrogen injection doses;

[0045] In step S3, the structural layer sample is placed in a heat treatment furnace for annealing. Under a helium atmosphere, the annealing temperature is 500-900℃ and the annealing time is 0.5-12h. The thickness of the vanadium nitride layer is controlled by adjusting different annealing processes.

[0046] Prior to ion implantation, a process S0 for preparing the vanadium metal substrate layer is also included, comprising the following steps:

[0047] S0-1, Smelting: High-purity dendritic vanadium particles are melted into vanadium liquid using a large-capacity regenerative smelting furnace and fed into the casting and rolling mill through a guide channel. During this process, a refining agent is added and degassing and slag removal processes are completed.

[0048] S0-2, Rolling: The vanadium liquid smelted in step S0-1 is introduced into a casting and rolling mill to be cast into a billet, and then the billet is continuously cold rolled until the thickness requirement is met, during which different degrees of homogenization annealing are carried out.

[0049] S0-3 Cleaning: The bundled vanadium foil is ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 5-10 minutes in sequence, and then dried to obtain the required vanadium metal substrate layer.

[0050] The preparation method will be described in detail below with reference to specific embodiments.

[0051] Example 1:

[0052] like Figure 1 The diagram shown illustrates the preparation process of a composite membrane for hydrogen purification from ammonia decomposition based on a high-temperature stable surface catalytic material. The specific preparation process is as follows:

[0053] Step 1: Ultrasonic cleaning of V-metal substrate

[0054] The cut V-shaped metal substrate was cleaned using an ultrasonic cleaner. During cleaning, acetone, anhydrous ethanol, and deionized water were used sequentially for 10 minutes each, followed by drying.

[0055] Step 2: Argon plasma cleaning of V metal substrate

[0056] The V metal substrate was cleaned using an argon ion beam while maintaining a vacuum level of less than 1 × 10⁻⁶ within the chamber. -4 The operating pressure is 0.05 Pa, the argon gas flow rate is 8 sccm, the low-energy ion beam energy is 1400 eV, and the beam current density is 10 mA / cm². 2 The bombardment lasted for 20 minutes.

[0057] Step 3: N plasma injection

[0058] Nitrogen gas is introduced into the reaction chamber, and N plasma is injected using an N ion implanter. The chamber vacuum pressure is 2 × 10⁻⁶. -4 Pa, nitrogen ion implantation energy 50 keV; implantation temperature 200℃; implantation dose 4 × 10⁻⁶. 16 ions / cm 2 .

[0059] Step 4: Annealing heat treatment

[0060] The sample was placed in a heat treatment furnace for annealing under a helium atmosphere at a temperature of 600°C for 1 hour.

[0061] Digital photographs of the VN / V / VN hydrogen separation composite membrane prepared by the above method, such as... Figure 2 As shown.

[0062] Example 2:

[0063] The preparation method is the same as in Example 1, except that the nitrogen ion implantation energy in step 3 is 60 keV and the implantation dose is 8 × 10⁻⁶. 16 ions / cm 2 Except for the above, the remaining steps and parameters are the same as in Example 1.

[0064] Figure 3 The image shows the XRD pattern of VN, with the peak position corresponding to PDF card #78-1315.

[0065] like Figure 4 As shown, the catalytic activity of VN prepared under different conditions was characterized using an electrochemical hydrogen evolution assay. Electrochemical hydrogen evolution catalysis and the catalytic dissociation of hydrogen molecules on the membrane surface share similar steps, both involving the adsorption and desorption of hydrogen on the material surface. Experiments revealed that with increasing N ion implantation dose, the hydrogen evolution overpotential and Tafel slope of the VN film gradually decreased, while the catalytic activity gradually increased.

[0066] The hydrogen gas purification test was carried out by using the ammonia decomposition hydrogen gas separation and purification membrane of examples 1-2, and the test method was as follows:

[0067] A hydrogen permeation device and a composite membrane material were used to form a set of hydrogen purification device, the hydrogen permeation mold was divided into two parts of upstream and downstream, and the composite membrane was placed between the two parts of the mold. In order to make the mold have good air tightness, and prevent the membrane from being subjected to large stress concentration during the fastening process, oxygen-free copper gaskets with an outer diameter of 16 mm and an inner diameter of 8 mm were placed on both sides of the membrane, and air tightness check was carried out. The composite membrane sample was fastened in the upstream and downstream molds by bolts, and then the upstream and downstream ports of the mold were connected to the device. After the pipeline was connected, 0.15 MPa of hydrogen-containing mixed gas was filled from the upstream end, heated to 600 DEG C under the condition and kept for 30 min, so that the temperature of each part of the composite membrane and the mold inside was uniform, and the composite membrane was activated. When the hydrogen absorption of the composite membrane reached saturation, the pressure indicator was stable, and the hydrogen permeation performance test was started: the upstream pressure was increased from 0.2 MPa, with an interval of 0.05 MPa, until it increased to 0.8 MPa, and the stable hydrogen permeation flow value was recorded under each pressure, and the downstream pressure was always maintained at 0.1 MPa.

[0068] Figure 5 The relationship curve of the hydrogen permeation coefficient Ф of the VN / V / VN composite membrane in examples 1-2 and the temperature T was given. The results showed that the hydrogen permeation performance of example 2 was better than that of example 1 at the same temperature. The hydrogen permeation performance of example 2 was close to that of pure Pd at 500 DEG C, and close to that of pure V at 800 DEG C.

[0069] In addition, the stability of the hydrogen permeation flow of the composite membrane was tested, and the method was as follows: another composite membrane which had not been subjected to hydrogen permeation was taken, and the previous preparation steps were the same as described above. During the hydrogen permeation test, the temperature was kept at 873 K, the upstream pressure was kept at 0.8 MPa, and the downstream pressure was kept at 0.1 MPa. The hydrogen permeation test was carried out for 30 hours, and the change of the hydrogen permeation flow with time was recorded.

[0070] Figure 6 The hydrogen permeation test curve of the VN / V / VN composite membrane prepared at different N ion implantation doses at 600 DEG C was given, wherein the upstream pressure was 0.8 MPa, and the downstream pressure was 0.1 MPa. The results showed that the hydrogen permeation stability of examples 1 and 2 was good. It fully showed that the VN structure was stable, and there was no mutual diffusion with V. In contrast, the Pd / V / Pd composite membrane would appear mutual diffusion at more than 400 DEG C.

[0071] In addition, after the gas chromatograph-mass spectrometer test, the final hydrogen purity was greater than or equal to 99.999%.

[0072] The vanadium nitride catalytic layer has excellent ability of catalyzing hydrogen molecule dissociation and hydrogen atom polymerization, can provide lower surface restriction when hydrogen permeation at high temperature above 450 DEG C, and improve hydrogen permeation performance of the composite membrane. The vanadium nitride catalytic layer is stable in structure, and can improve hydrogen permeation stability of the composite membrane without interdiffusion with the vanadium metal layer at high temperature. Meanwhile, the vanadium nitride catalytic layer can inhibit combination of nitrogen and hydrogen, and weaken reverse reaction process of ammonia decomposition.

[0073] The present application performs structure regulation on the surface of the vanadium metal layer, and facilitates in-situ growth of the vanadium nitride catalytic layer with controllable thickness on the substrate, and is more suitable for large-scale industrial production.

[0074] The unmentioned part of the present application is applicable to the prior art.

[0075] Obviously, the above examples are only illustrative, and not limiting. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. All the embodiments are not required to be enumerated, and the changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A composite membrane for hydrogen purification by ammonia decomposition based on high-temperature stable surface catalytic material, characterized in that, The composite film is composed of a substrate layer and catalytic layers distributed on both sides of the substrate layer, wherein the substrate layer is a vanadium metal layer, and the catalytic layers are vanadium nitride layers; the vanadium nitride layers are formed in situ on the surface of the substrate layer by an ion implantation process, and the ion implantation process comprises the following steps: S1, ion cleaning of both sides of the substrate vanadium metal layer surface by argon plasma to complete surface treatment of the vanadium metal layer; S2, nitrogen ion implantation on both sides of the treated vanadium metal layer surface to form vanadium nitride, thereby obtaining a vanadium nitride / vanadium metal / vanadium nitride "sandwich" structure layer; S3, annealing treatment of the structure layer prepared in step S2 to improve the uniformity and stability of the vanadium nitride structure and eliminate structural defects, thereby obtaining the required composite film.

2. The ammonia-decomposition hydrogen purification composite membrane based on a high-temperature stable surface catalytic material according to claim 1, characterized in that, The chemical formula of the vanadium nitride is VNx, wherein 0.2≤x≤1.

3. The ammonia-decomposition hydrogen purification composite membrane based on high-temperature stable surface catalytic material according to claim 1, characterized in that, The substrate layer material is one of pure V, V-Ni alloy, V-Cr alloy, V-Cu alloy, V-Fe alloy, V-Al alloy, V-Co alloy, V-Mo alloy, V-W alloy, V-Pd alloy, V-Ti-Ni alloy, V-Fe-Al alloy, V-Mo-W alloy, V-Cu-Al alloy, V-Co-Al alloy, V-Ni-Al alloy and vanadium-based high-entropy alloy.

4. The ammonia-decomposition hydrogen purification composite membrane based on high-temperature stable surface catalytic material according to claim 1, characterized in that, The thickness of the substrate layer is 10-500 μm, and the diameter is 0.5 cm-100 cm; the thickness of the catalytic layer is 2-500 nm, and the diameter is consistent with the diameter of the substrate layer.

5. The ammonia-decomposition hydrogen purification composite membrane based on high-temperature stable surface catalytic materials according to claim 3, characterized in that, The thickness of the substrate layer is 25-250 μm, and the diameter is 1 cm-50 cm; the thickness of the catalytic layer is 20-300 nm, and the diameter is consistent with the diameter of the substrate layer.

6. The ammonia decomposition hydrogen purification composite film based on high-temperature stable surface catalytic material according to claim 1, characterized in that, The vacuum degree in the chamber is less than 10 -4 The flow rate of argon gas is 5-20 sccm, the working pressure is 0.02-0.08 Pa, the beam current density is 10-20 mA / cm 2 The argon ion energy is 400-1000 eV, and the cleaning time is 20-40 min. In the step S2, nitrogen is introduced into the reaction chamber, N plasma is injected by the N ion implanter, the vacuum degree of the chamber is 2×10 -3 -1×10 -5 Pa, the nitrogen ion injection energy is 30-80 keV, the injection temperature is 25-500 ℃, the injection dose is 1×10 15 ions / cm 2 -9.9×10 17 ions / cm 2 , and the composition of the vanadium nitride can be adjusted by controlling different nitrogen injection doses. In step S3, the structure layer sample is placed in a heat treatment furnace for annealing treatment, the annealing temperature is 500-900 ℃ under a helium atmosphere, and the annealing time is 0.5-12 h, and different annealing processes are used to control the thickness of the vanadium nitride layer.

7. The ammonia-decomposition hydrogen purification composite membrane based on high-temperature stable surface catalytic materials according to claim 1, characterized in that, Before ion implantation, the preparation process S0 of the substrate vanadium metal layer is further included, comprising the following steps: S0-1, smelting: high-purity dendritic vanadium particles are melted into vanadium liquid by using a large-capacity regenerative smelting furnace, and a refining agent is added during the process, and a degassing and deslagging process is completed; S0-2, rolling: the vanadium liquid after smelting in step S0-1 is introduced into a casting mill to cast and roll into a blank, and the blank is continuously cold-rolled until the thickness requirement is met, and different degrees of homogenizing annealing are performed during the process; S0-3, cleaning: the rolled vanadium foil is sequentially cleaned by ultrasonic cleaning with acetone, anhydrous ethanol and deionized water for 5-10 min, and then dried, thereby obtaining the required substrate vanadium metal layer.

8. Application of the ammonia decomposition hydrogen purification composite film based on high-temperature stable surface catalytic material according to any one of claims 1-7 in continuously and stably separating and purifying hydrogen from ammonia decomposition mixed gas.

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