Ternary composite catalytic materials, their preparation methods and applications

Abstract

This invention relates to the field of photocatalysis, and discloses a ternary composite catalytic material, its preparation method, and its application. The ternary composite catalytic material comprises bismuth vanadate, titanium dioxide, and an active metal, wherein the active metal is selected from at least one of iron, ruthenium, nickel, cobalt, and copper; wherein the bismuth vanadate and / or titanium dioxide contain oxygen vacancies, and the total oxygen vacancies content in the catalytic material is not less than 2%. The ternary composite catalytic material provided by this invention can significantly improve the efficiency of ammonia decomposition.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, specifically to a ternary composite catalytic material, its preparation method, and its application. Background Technology

[0002] Since the beginning of the 21st century, clean energy, represented by hydrogen energy, has experienced rapid development. Simultaneously, researchers are increasingly focusing on using renewable energy sources such as solar and wind power to drive hydrogen production reactions. Currently, commonly used catalytic conversion pathways mainly include thermocatalysis, photocatalysis, and electrocatalysis. Traditional thermocatalytic methods have high energy consumption, hindering large-scale applications. Utilizing solar energy to assist catalytic processes for hydrogen production holds promise for reducing dependence on fossil fuels. Ammonia is a traditional bulk chemical with a hydrogen content of 17.6% by mass, high energy density, and is easily liquefied, stored, and transported. Furthermore, its decomposition process only produces hydrogen and nitrogen, with no carbon emissions. Therefore, ammonia is a potential liquid hydrogen storage medium, potentially alleviating the problems of uneven regional distribution and large-scale transportation difficulties associated with hydrogen energy.

[0003] Patent application CN112473747A discloses a method for preparing and applying an ultrathin two-dimensional metal phthalocyanine / bismuth vanadate heterojunction photocatalyst controlled by gold nanoparticles. This application addresses the problems of low photogenerated carrier separation efficiency and lack of catalytic active centers in existing bismuth vanadate-based heterojunction composite systems.

[0004] Patent application CN110387737A discloses a method for preparing a graphene-titanium dioxide-bismuth vanadate photocatalytic functional fabric, as follows: (1) the pretreated fabric is subjected to plasma treatment; (2) the fabric treated in step 1 is immersed in a graphene oxide dispersion, and after extrusion, the fabric is rolled up and wrapped with a polyethylene film, and then microwaved; (3) the fabric treated in step 2 is immersed in a titanium dioxide hydrosol, and after extrusion, the fabric is first subjected to plasma treatment, and then ultraviolet irradiation treatment; (4) the fabric treated in step (3) is immersed in a bismuth vanadate sol, and after extrusion, the fabric is rolled up and wrapped with a polyethylene film, and then microwaved again, followed by washing and drying to obtain the graphene-titanium dioxide-bismuth vanadate photocatalytic functional fabric. However, the synthesis method of this system is relatively complex and is not suitable for ammonia decomposition to produce hydrogen. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide a ternary composite catalytic material, its preparation method and application, which can significantly improve the efficiency of ammonia decomposition.

[0006] To achieve the above objectives, the first aspect of the present invention provides a ternary composite catalytic material, wherein the catalytic material comprises bismuth vanadate, titanium dioxide, and an active metal, wherein the active metal is selected from at least one of iron, ruthenium, nickel, cobalt, and copper; wherein the bismuth vanadate and / or titanium dioxide contain oxygen vacancies, and the total content of oxygen vacancies in the catalytic material is not less than 2%.

[0007] Preferably, both bismuth vanadate and titanium dioxide in the catalytic material contain oxygen vacancies.

[0008] Preferably, the total oxygen vacancy content in the catalytic material is 2-10%, more preferably 5-8%.

[0009] A second aspect of this invention provides a method for preparing a ternary composite catalytic material, wherein the method includes the following steps:

[0010] (1) A mixture A containing bismuth source and acid is mixed with a mixture B containing metavanadate and alkali, and a contact reaction is carried out, wherein the temperature of the contact reaction does not exceed 100°C.

[0011] (2) The contact reaction product obtained in step (1) is mixed with titanium source and solvent to carry out a solvothermal reaction;

[0012] (3) The solvothermal reaction product obtained in step (2) is mixed with the active metal precursor and then calcined under a reducing atmosphere to obtain a ternary composite catalytic material. The active metal is selected from at least one of iron, ruthenium, nickel, cobalt and copper.

[0013] The third aspect of this invention provides a ternary composite catalytic material prepared by the preparation method described in the second aspect.

[0014] The fourth aspect of this invention provides the application of the elemental composite catalytic material described in the first or third aspect in the photocatalytic ammonia decomposition to produce hydrogen.

[0015] The ternary composite catalytic material provided by this invention, by introducing oxygen vacancies into bismuth vanadate and / or titanium dioxide, can increase the number of active sites in the ternary composite catalytic material to promote the activation of ammonia molecules and improve the efficiency of ammonia decomposition for hydrogen production. Simultaneously, the tight interfacial contact between bismuth vanadate and titanium dioxide is beneficial for further promoting photogenerated charge migration and improving the photocatalytic efficiency of ammonia decomposition for hydrogen production; furthermore, by introducing active metals as active sites, the ammonia decomposition activity is further enhanced.

[0016] The preparation method provided by this invention employs in-situ synthesis to form a tight interfacial contact between bismuth vanadate and titanium dioxide. Oxygen vacancies are introduced through calcination in a reducing atmosphere, effectively controlling the defect content. The preparation process is simple, reproducible, and easily scaled up for mass production. Attached Figure Description

[0017] Figure 1 This is a transmission electron microscope image of the ternary composite catalytic material in Example 1;

[0018] Figure 2 The image shows the Mott-Schottky curve of the ternary composite catalyst material in Example 1. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] The first aspect of the present invention provides a ternary composite catalytic material, wherein the catalytic material comprises bismuth vanadate, titanium dioxide, and an active metal, wherein the active metal is selected from at least one of iron, ruthenium, nickel, cobalt, and copper; wherein the bismuth vanadate and / or titanium dioxide contain oxygen vacancies, and the total content of oxygen vacancies in the catalytic material is not less than 2%.

[0021] The ternary composite catalytic material provided by this invention, a heterojunction formed by bismuth vanadate and titanium dioxide, increases the number of active sites and improves the efficiency of ammonia decomposition for hydrogen production by introducing oxygen vacancies into bismuth vanadate and / or titanium dioxide. Simultaneously, the tight interfacial contact between bismuth vanadate and titanium dioxide further promotes photogenerated charge migration, thereby enhancing the efficiency of ammonia decomposition for hydrogen production.

[0022] In this invention, oxygen defects in the ternary composite catalytic material refer to oxygen content in the ternary composite catalytic material being less than its theoretical stoichiometric content. Oxygen defects are measured by X-ray photoelectron spectroscopy analysis. The specific test conditions are: using high-resolution O1s spectrum peak fitting to determine lattice oxygen and defect oxygen signals, thereby calculating the molar percentage of oxygen defects as: defect oxygen / (defect oxygen + lattice oxygen) × 100%.

[0023] The ternary composite catalytic material provided by this invention can contain oxygen vacancies in bismuth vanadate, titanium dioxide, or both. Preferably, both bismuth vanadate and titanium dioxide contain oxygen vacancies. Under these preferred conditions, it is beneficial to further improve the ammonia decomposition hydrogen production efficiency of the photo-ternary composite catalytic material.

[0024] This invention does not impose particular limitations on the oxygen defect content of bismuth vanadate and titanium dioxide, as long as the total oxygen defect content in the ternary composite catalyst is not less than 2%. Preferably, the total oxygen defect content in the ternary composite catalyst is 2-10%, more preferably 5-8%. Under these preferred oxygen defect contents, it is beneficial to increase the number of active sites in the ternary composite catalyst and improve the efficiency of ammonia decomposition for hydrogen production. When the oxygen defect content is too low, the number of active sites in the material is limited; when the oxygen defect content is too high, it will affect the lattice stability, leading to a decrease in the stability of the ternary composite material and affecting its reactivity.

[0025] In this invention, preferably, the free carrier density of the catalytic material is greater than 10, as determined by electrochemical Mott-Schottky curve analysis. 22 cm -3 Further preferred is 2×10 22 -8×10 22 cm -3 A further preferred value is 3×10 22 -6×10 22 cm -3 The advantage of this preferred embodiment is that it facilitates faster photogenerated charge transport and improves reaction efficiency. However, when the free carrier density is not within the above-mentioned range, it suffers from poor photogenerated charge transport performance.

[0026] In this invention, free carrier density refers to the density of freely moving electrons in a semiconductor. The free carrier density is calculated by measuring the slope of the Mott-Schottky curve using an electrochemical workstation.

[0027] In this invention, there is no particular limitation on the type of active metal; any active metal suitable for ammonia decomposition to produce hydrogen in the art is applicable to this invention. Preferably, the active metal is selected from iron and / or cobalt and ruthenium.

[0028] In this invention, the selection range for the content of each component in the ternary composite catalytic material is relatively wide. Preferably, based on the total amount of the catalytic material, the content of bismuth vanadate is 20-60 wt%, the content of titanium dioxide is preferably 20-60 wt%, and the content of the active metal (calculated as an element) is 5-50 wt%. More preferably, based on the total amount of the catalytic material, the content of bismuth vanadate is 30-50 wt%, the content of titanium dioxide is 30-50 wt%, and the content of the active metal (calculated as an element) is 8-20 wt%.

[0029] In this invention, the reaction efficiency of ammonia decomposition to produce hydrogen is improved by combining the noble metal ruthenium with a non-noble metal. Preferably, the mass ratio of ruthenium to (iron + cobalt) is 0.6-1.5:1.

[0030] In this invention, the content of each component of the ternary composite catalytic material is obtained by inductively coupled plasma atomic emission spectroscopy and X-ray photoelectron spectroscopy.

[0031] A second aspect of this invention provides a method for preparing a ternary composite catalytic material, wherein the method includes the following steps:

[0032] (1) A mixture A containing bismuth source and acid is mixed with a mixture B containing metavanadate and alkali, and a contact reaction is carried out, wherein the temperature of the contact reaction does not exceed 100°C.

[0033] (2) The contact reaction product obtained in step (1) is mixed with titanium source and solvent to carry out a solvothermal reaction;

[0034] (3) The solvothermal reaction product obtained in step (2) is mixed with the active metal precursor and then calcined under a reducing atmosphere to obtain a ternary composite catalytic material. The active metal is selected from at least one of iron, ruthenium, nickel, cobalt and copper.

[0035] The preparation method provided by this invention employs in-situ synthesis to form a tight interfacial contact between bismuth vanadate and titanium dioxide. Oxygen defects are introduced through calcination in a reducing atmosphere, and the defect content can be effectively controlled. The preparation process is simple, reproducible, and easy to scale up for mass production.

[0036] In this invention, there are no particular limitations on the preparation method of mixture A. Preferably, in step (1), the mixture A containing bismuth source and acid is prepared by mixing bismuth source and acid.

[0037] In this invention, there are no particular limitations on the preparation method of mixture B. Preferably, in step (1), the mixture B containing metavanadate and alkali is prepared by mixing metavanadate and alkali.

[0038] In this invention, the range of suitable amounts for the bismuth source and metavanadate is wide, as long as the requirements for bismuth vanadate synthesis are met. Preferably, the molar ratio of the bismuth source (based on bismuth element) to the metavanadate (based on vanadium element) is 0.5-5:1, more preferably 0.8-1.2:1.

[0039] In this invention, preferably, H + The molar amount of the acid and OH - The molar amounts of the bases are equal.

[0040] In this invention, preferably, in step (1), the acid is provided by an aqueous solution of the acid, and the concentration of the aqueous solution of the acid is 0.5-4 mol / L, more preferably 1-3 mol / L, for example, it can be 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L and any value between any two groups.

[0041] In this invention, there is no particular limitation on the amount of the aqueous acid solution used, as long as it meets the requirements of the contact reaction. Those skilled in the art can select the appropriate amount based on actual needs. Preferably, the amount of the aqueous acid solution used is 200-800 mL relative to 1 mol of the bismuth source, more preferably 350-700 mL.

[0042] In this invention, preferably, the alkali is provided by an aqueous solution of alkali, the concentration of which is 0.5-4 mol / L, more preferably 1-3 mol / L, for example, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, or any value between any two groups. In this invention, the concentration of the aqueous acid solution and the concentration of the aqueous alkali solution can be the same or different, and this invention does not impose any particular limitation on this.

[0043] In this invention, the amount of the aqueous solution of alkali is not particularly limited, as long as it meets the requirements of the contact reaction. Those skilled in the art can select the appropriate amount based on actual needs. Preferably, the amount of the aqueous solution of alkali is 200-800 mL relative to 1 mol of the metavanadate (based on vanadium element), and more preferably 350-700 mL.

[0044] In this invention, the range of acids selected is relatively wide, and conventional organic or inorganic acids in the art can be used. This invention specifically limits the selection. Preferably, the acid is selected from at least one of nitric acid, sulfuric acid, phosphoric acid, oxalic acid, acetic acid, and hydrochloric acid, and more preferably nitric acid.

[0045] In this invention, the selection range of specific types of alkali is relatively wide. Preferably, the alkali can be an alkali metal hydroxide, such as sodium hydroxide and / or potassium hydroxide.

[0046] In this invention, there is no particular limitation on the specific type of bismuth source; any source that can provide bismuth is acceptable. Conventional bismuth-containing compounds in the art can be used in this invention. Preferably, the bismuth source is selected from at least one of bismuth nitrate, bismuth trichloride, and basic bismuth salicylate.

[0047] In this invention, there is no particular limitation on the type of metavanadate. Preferably, the metavanadate is selected from at least one of sodium metavanadate, potassium metavanadate, and ammonium metavanadate.

[0048] In this invention, preferably, step (1) includes: adding the mixture A containing bismuth source and acid to the mixture B containing metavanadate and alkali under stirring conditions to carry out a contact reaction. In this invention, there are no particular limitations on the stirring conditions, as long as they can promote the reaction; those skilled in the art can select the appropriate conditions according to actual needs.

[0049] In this invention, preferably, the addition rate of the mixture A containing the bismuth source and the acid is 0.5-5 mL / min relative to 10 mL of the mixture B containing metavanadate and alkali. The preferred embodiment described above has the advantage of uniform mixing of the precursor solution.

[0050] In this invention, preferably, in step (1), the conditions for the contact reaction include: a temperature of room temperature to 80°C, for example, room temperature, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, and any value between any two groups; and a time of 0.5-24 hours, for example, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, and any value between any two groups. In this invention, the contact reaction in step (1) can be carried out under relatively mild reaction conditions, with a reaction temperature not exceeding 100°C, preferably at room temperature to 80°C. In this invention, "room temperature" refers to 25±5°C. The inventors of this invention discovered in their research that bismuth vanadate synthesized using a lower contact reaction temperature has uniform particle size, which helps to enhance the contact strength between the in-situ synthesized titanium dioxide and bismuth vanadate, and also helps to control the oxygen defect content. In contrast, existing technologies for preparing bismuth vanadate via precipitation often require high temperature and high pressure conditions, with reaction temperatures typically above 150°C.

[0051] In this invention, titanium dioxide is synthesized in situ on a bismuth vanadate matrix by mixing the product obtained in step (1) with a titanium source and a solvent and carrying out a solvothermal reaction, thereby forming a tight interfacial contact between bismuth vanadate and titanium dioxide. In this invention, the type of titanium source is not particularly limited, as long as titanium can be provided. Preferably, the titanium source is a titanium-containing compound, preferably selected from at least one of tetrabutyl titanate, titanium sulfate, and titanium tetrachloride. Using the above-mentioned preferred embodiments is beneficial for promoting photogenerated charge migration and improving the efficiency of hydrogen production from ammonia decomposition.

[0052] In this invention, step (1) further includes: performing solid-liquid separation on the contact reaction product. The solid-liquid separation can be performed using conventional operating methods and conditions in the art, and this invention does not have any particular limitations on this; for example, centrifugation can be used for solid-liquid separation. The solid product obtained from the solid-liquid separation is used in step (2).

[0053] In this invention, the term "solventricular reaction" refers to a solvothermal reaction in a broad sense: a reaction that occurs in a closed system, such as an autoclave, in the presence of water or a non-aqueous solvent, under certain temperature and autogenous pressure of the solution. It is understood that in this invention, the solvothermal reaction solution system depends on the type of solvent and does not necessarily contain water.

[0054] In this invention, there are no particular limitations on the specific type and amount of solvent used in step (2), as long as it can help disperse the contact reaction product obtained in step (1) and the titanium source. Conventional solvents in the art are applicable to this invention. In order to further improve the dispersion effect of the titanium source and improve the binding strength of the in-situ synthesized titanium dioxide, preferably, the solvent is an alcohol, preferably a monohydric alcohol and / or a polyhydric alcohol, more preferably at least one of C1-C10 monohydric alcohols, dihydric alcohols and trihydric alcohols, preferably at least one of ethanol, ethylene glycol, n-propanol, isopropanol, 1,2-propanediol, 1,3-propanediol and glycerol, more preferably at least one of ethanol, isopropanol and glycerol.

[0055] In this invention, preferably, in step (2), the conditions for the solvothermal reaction include: a temperature of 90-200℃, for example, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, and any value between any two groups; and a time of 12-48h, for example, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h, 48h, and any value between any two groups.

[0056] In this invention, preferably, in step (3), the active metal is selected from iron and / or cobalt and ruthenium.

[0057] In this invention, there is no particular limitation on the type of active metal precursor, as long as it can provide each active metal element. Preferably, in step (3), the active metal precursor is selected from soluble compounds of each active metal, and more preferably from at least one of nitrates, chlorides and sulfates of each active metal. This invention does not specifically limit its type.

[0058] In this invention, the introduction of active metals through mixing facilitates close contact between the active metals and titanium dioxide and / or bismuth vanadate. Preferably, in step (3), the mixing is mechanical mixing and / or rotary drying, more preferably rotary drying. Compared to the impregnation method used in the prior art, this method offers the advantage of uniform metal dispersion.

[0059] In this invention, there are no particular limitations on the specific operation of mechanical mixing, as long as the introduction of active metals can be achieved. Those skilled in the art can make selections according to actual needs, such as mechanical mixing in a ball mill.

[0060] In this invention, preferably, in step (3), the conditions for rotary evaporation drying include a temperature of 70-90°C. The advantage of this preferred embodiment is that the metal is uniformly dispersed. In this invention, there are no particular limitations on the specific operation method of rotary evaporation drying. Preferably, in step (3), the rotary evaporation drying includes dispersing the active metal precursor and the solvothermal reaction product from step (2) in a solvent (preferably water), and then performing rotary evaporation drying at 70-90°C.

[0061] In this invention, the range of selection for roasting conditions is relatively wide. Preferably, in step (3), the roasting conditions include: a temperature of 350-600℃, for example, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃. ℃, 600℃, and any value between any two groups; time is 2-8h, for example, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, and any value between any two groups; heating rate is 2-10℃ / min, for example, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, and any value between any two groups.

[0062] In this invention, to further catalyze the reduction of oxygen vacancies in the material, the flow rate of the reducing atmosphere is preferably 10-80 mL / min, more preferably 20-60 mL / min, and can be, for example, 10 mL / min, 20 mL / min, 25 mL / min, 30 mL / min, 35 mL / min, 40 mL / min, 45 mL / min, 50 mL / min, 55 mL / min, 60 mL / min, or any value between any two groups.

[0063] In this invention, preferably, the reducing atmosphere includes H2 and optionally an inert gas. The type of inert gas is not particularly limited in this invention; for example, it may be nitrogen, argon, or neon.

[0064] In this invention, preferably, based on the total volume of the reducing atmosphere, the total H2 content is 5-100% by volume, more preferably 10-50% by volume, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% by volume.

[0065] In this invention, the defect content can be effectively controlled by adjusting the roasting time, temperature and reducing atmosphere concentration, thereby increasing the number of active sites and improving the efficiency of ammonia decomposition for hydrogen production.

[0066] In this invention, step (3) further includes: performing solid-liquid separation, washing, and drying on the product obtained from the calcination. This invention does not impose particular limitations on the specific conditions for the solid-liquid separation, washing, and drying; all can be performed using conventional methods in the art.

[0067] In this invention, preferably, the amounts of the bismuth source, titanium source, and active metal precursor are such that the content of bismuth vanadate in the prepared catalytic material is 20-80 wt%, the content of titanium dioxide is 20-80 wt%, and the content of the active metal (in elemental terms) is 5-20 wt%; more preferably, based on the total amount of the catalytic material, the content of bismuth vanadate is 30-50 wt%, the content of titanium dioxide is 30-50 wt%, and the content of the active metal (in elemental terms) is 8-20 wt%.

[0068] In this invention, preferably, the amount of the active metal precursor is such that the mass ratio of ruthenium to (iron + cobalt) in the prepared catalytic material is 0.6-1.5:1 (based on elemental composition).

[0069] A third aspect of this invention provides a ternary composite catalytic material prepared by the method described in the second aspect. This ternary composite catalytic material possesses the properties of the ternary composite catalytic material described in the first aspect.

[0070] The fourth aspect of this invention provides the application of the ternary composite catalytic material described in the first or third aspect in the photocatalytic ammonia decomposition to produce hydrogen.

[0071] In this invention, preferably, the ammonia raw material is provided by an ammonia solution with a concentration of 0.01-0.1 mol / L.

[0072] In this invention, the conditions for the ammonia decomposition to hydrogen production reaction are not particularly limited. Preferably, the conditions for the ammonia decomposition to hydrogen production reaction include: a reaction temperature of 0-40°C, and an amount of 0.05-0.5 g of ternary composite catalyst relative to 0.01 mol of ammonia aqueous solution.

[0073] The present invention will be described in detail below through embodiments.

[0074] Unless otherwise specified, all raw materials used in the following embodiments are commercially available.

[0075] In the following examples, "room temperature" refers to 25±5℃.

[0076] In the following examples, the content of each component of the ternary composite catalytic material was obtained by inductively coupled plasma atomic emission spectroscopy and X-ray photoelectron spectroscopy.

[0077] Example 1

[0078] (1) Weigh 67.4 g of bismuth nitrate pentahydrate into 60 mL of 2.5 mol / L dilute nitric acid to prepare mixture A; weigh 16.9 g of sodium metavanadate into 60 mL of 2.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0079] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 191.8 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and reacted at 90 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0080] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and the solid from step (2) above and disperse them in 200mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in a 15% H2 / Ar atmosphere with a gas flow rate of 40mL / min, a calcination temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material. Figure 1 The image shows a transmission electron microscope image of the ternary composite material, which reveals that the sample exists in the form of nanoparticles with obvious intergranular dislocations. Figure 2 These are the Mott-Schottky curve test results for ternary composite materials, based on the free carrier density = 2e⁰. -1 ε -1 ε0 -1 |d(C -2 ) / dV| -1 Calculate, where e0 is the elementary charge value (1.60 × 10⁻⁶). -19 C), ε is the relative permittivity of the material (ε=5.5), ε0 is the vacuum permittivity (8.85×10⁻⁶). -12 F m -1 ), d(C -2 ) / dV is the slope of the Mott-Schottky curve.

[0081] Example 2

[0082] (1) Weigh 74.9 g of bismuth nitrate pentahydrate into 60 mL of 1.5 mol / L dilute nitric acid to prepare mixture A; weigh 18.8 g of sodium metavanadate into 60 mL of 1.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0083] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 170.4 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and reacted at 100 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0084] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and the solid from step (2) above and disperse them in 200mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in a 15% H2 / Ar atmosphere with a gas flow rate of 40mL / min, a calcination temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0085] Example 3

[0086] (1) Weigh 44.9 g of bismuth nitrate pentahydrate into 60 mL of 3.0 mol / L dilute nitric acid to prepare mixture A; weigh 11.3 g of sodium metavanadate into 60 mL of 3.0 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 5 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0087] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 255.7 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and hydrothermal solvothermal reaction was carried out at 90 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0088] (3) Weigh 10.3g of ruthenium trichloride and 24.7g of cobalt nitrate hexahydrate and the solid from step (2) above and disperse them in 200mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in a 15% H2 / Ar atmosphere with a gas flow rate of 45mL / min, a calcination temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0089] Example 4

[0090] (1) Weigh 89.8g of bismuth nitrate pentahydrate into 60mL of 1.5mol / L dilute nitric acid to prepare mixture A; weigh 22.6g of sodium metavanadate into 60mL of 1.5mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4mL / min relative to 10mL of the mixture B; after stirring the reaction thoroughly for 1h, centrifuge to recover the mixture.

[0091] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 127.8 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and hydrothermal solvothermal reaction was carried out at 90 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0092] (3) Weigh 20.5g of ruthenium trichloride and the solid from step (2) above and disperse it in 200mL of water. Dry it by rotary evaporation at 70℃, and then calcine it in a 15% H2 / Ar atmosphere with a gas flow rate of 40mL / min, a calcination temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool it to room temperature to obtain the ternary composite catalyst material.

[0093] Example 5

[0094] (1) Weigh 67.4 g of bismuth nitrate pentahydrate into 60 mL of 2.5 mol / L dilute nitric acid to prepare mixture A; weigh 16.9 g of sodium metavanadate into 60 mL of 2.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0095] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 191.8 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and hydrothermal solvothermal reaction was carried out at 90 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0096] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and the solid from step (2) above and disperse them in 200mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in a 7 vol% H2 / Ar atmosphere with a gas flow rate of 20mL / min, a calcination temperature of 350℃, a time of 2h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0097] Example 6

[0098] (1) Weigh 67.4 g of bismuth nitrate pentahydrate into 60 mL of 2.5 mol / L dilute nitric acid to prepare mixture A; weigh 16.9 g of sodium metavanadate into 60 mL of 2.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0099] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 191.8 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and hydrothermal solvothermal reaction was carried out at 90 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0100] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and the solid from step (2) above and disperse them in 200mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in a 70% H2 / Ar atmosphere with a gas flow rate of 60mL / min, a calcination temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0101] Example 7

[0102] (1) Weigh 67.4 g of bismuth nitrate pentahydrate into 60 mL of 2.5 mol / L dilute nitric acid to prepare mixture A; weigh 16.9 g of sodium metavanadate into 60 mL of 2.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0103] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 191.8 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and hydrothermal solvothermal reaction was carried out at 180 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0104] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and the solid from step (2) above and disperse them in 200mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in a 15% H2 / Ar atmosphere with a gas flow rate of 40mL / min, a calcination temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0105] Example 8

[0106] (1) Weigh 67.4 g of bismuth nitrate pentahydrate into 60 mL of 2.5 mol / L dilute nitric acid to prepare mixture A; weigh 16.9 g of sodium metavanadate into 60 mL of 2.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0107] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 191.8 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and hydrothermal solvothermal reaction was carried out at 90 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0108] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and impregnate the above solid. Then, calcine it in an atmosphere of 15% H2 / Ar, with a gas flow rate of 40mL / min, a calcine temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool it to room temperature to obtain a ternary composite catalyst.

[0109] Comparative Example 1

[0110] (1) Weigh 250 mL of anhydrous ethanol and add 383.5 g of tetrabutyl titanate. After stirring for 1 h, transfer the mixture to a reaction vessel lined with polytetrafluoroethylene. Perform a hydrothermal solvothermal reaction at 90 °C for 24 h. After the reaction, centrifuge, wash and dry the resulting solid.

[0111] (2) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and the solid from step (1) above and disperse them in 200mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in a 15 vol% H2 / Ar atmosphere with a gas flow rate of 40mL / min, a calcination temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0112] Comparative Example 2

[0113] (1) Weigh 67.4 g of bismuth nitrate pentahydrate into 60 mL of 2.5 mol / L dilute nitric acid to prepare mixture A; weigh 16.9 g of sodium metavanadate into 60 mL of 2.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, transfer it to a reaction vessel lined with polytetrafluoroethylene, and perform a hydrothermal solvothermal reaction at 90 °C for 24 h; after the reaction, centrifuge, wash and dry the obtained solid to obtain product C;

[0114] (2) Weigh 250 mL of anhydrous ethanol and add 191.8 g of tetrabutyl titanate. After stirring for 1 h, transfer the mixture to a reaction vessel lined with polytetrafluoroethylene. Perform a hydrothermal solvothermal reaction at 150 °C for 24 h. After the reaction, centrifuge, wash and dry the resulting solid to obtain product D.

[0115] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and grind and mix them with products C and D. Then, calcine them in a 15% H2 / Ar atmosphere with a gas flow rate of 40mL / min, a calcine temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0116] Comparative Example 3

[0117] (1) Weigh 67.4 g of bismuth nitrate pentahydrate into 60 mL of 2.5 mol / L dilute nitric acid to prepare mixture A; weigh 16.9 g of sodium metavanadate into 60 mL of 2.5 mol / L sodium hydroxide solution to prepare mixture B; at room temperature, slowly add A to B, with the addition rate of mixture A being 4 mL / min relative to 10 mL of the mixture B; after stirring the reaction thoroughly for 1 h, centrifuge to recover the mixture.

[0118] (2) The obtained product was dispersed in 250 mL of anhydrous ethanol and 191.8 g of tetrabutyl titanate was added. After stirring for 1 h, it was transferred to a reaction vessel with a polytetrafluoroethylene liner and hydrothermal solvothermal reaction was carried out at 90 °C for 24 h. After the reaction, the obtained solid was centrifuged, washed and dried.

[0119] (3) Weigh 10.3g of ruthenium trichloride and 36.2g of ferric nitrate nonahydrate and the solid from step (2) above and disperse them in 100mL of water. Dry them by rotary evaporation at 70℃, and then calcine them in an air atmosphere with a gas flow rate of 40mL / min, a calcine temperature of 450℃, a time of 4h, a heating rate of 5℃ per minute, and cool them to room temperature to obtain the ternary composite catalyst material.

[0120] In the above embodiments and comparative examples, the contents of bismuth vanadate, titanium dioxide, and active metal in the ternary composite catalytic materials are shown in Table 1, and the oxygen defect content and free carrier density are shown in Table 2.

[0121] Table 1

[0122] composition Example 1 <![CDATA[45%BiVO4-45%TiO2-5%Ru-5%Fe]]> Example 2 <![CDATA[50%BiVO4-40%TiO2-5%Ru-5%Fe]]> Example 3 <![CDATA[30%BiVO4-60%TiO2-5%Ru-5%Co]]> Example 4 <![CDATA[60%BiVO4-30%TiO2-10%Ru]]> Example 5 <![CDATA[45%BiVO4-45%TiO2-5%Ru-5%Fe]]> Example 6 <![CDATA[45%BiVO4-45%TiO2-5%Ru-5%Fe]]> Example 7 <![CDATA[45%BiVO4-45%TiO2-5%Ru-5%Fe]]> Example 8 <![CDATA[45%BiVO4-45%TiO2-5%Ru-5%Fe]]> Comparative Example 1 <![CDATA[90%TiO2-5%Ru-5%Fe]]> Comparative Example 2 <![CDATA[45%BiVO4-45%TiO2-5%Ru-5%Fe]]> Comparative Example 3 <![CDATA[45%BiVO4-45%TiO2-5%Ru-5%Fe]]>

[0123] Table 2

[0124] Oxygen defect content (%) <![CDATA[Free carrier density (10 22 cm -3 )]]> Example 1 6.0 4.6 Example 2 6.0 4.5 Example 3 7.0 3.2 Example 4 6.0 2.8 Example 5 3.5 1.2 Example 6 10.0 2.2 Example 7 2.0 1.8 Example 8 5.0 1.2 Comparative Example 1 1.5 0.8 Comparative Example 2 0.8 0.4 Comparative Example 3 0.5 1.0

[0125] Photocatalytic ammonia decomposition hydrogen production activity test

[0126] The obtained catalyst was used to simulate the photocatalytic ammonia decomposition to hydrogen production reaction under sunlight. Activity testing was conducted using an online vacuum photocatalytic reactor with a 300W xenon lamp as the light source. The reaction conditions were: 0.1 g catalyst, 100 mL 0.1 mol / L ammonia solution, and a reaction temperature of 5 °C. Samples were taken every hour after the reaction started, and the average reaction rate over 6 hours was calculated. The products were analyzed using chromatography equipped with a flame ionization detector and a thermal conductivity detector, and quantification was performed using a pre-determined standard curve. The reaction mainly produced two products: N2 and H2, and a small amount of O2 from the water decomposition side reaction. The reaction results are shown in Table 3.

[0127] Table 3

[0128]

[0129] As can be seen from the table above, the catalytic material provided by this invention has excellent ammonia decomposition activity.

[0130] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A ternary composite catalytic material, characterized in that, The catalytic material comprises bismuth vanadate, titanium dioxide, and an active metal, wherein the active metal is selected from at least one of iron, ruthenium, nickel, cobalt, and copper; wherein the bismuth vanadate and / or titanium dioxide contain oxygen vacancies, and the total oxygen vacancies content in the catalytic material is not less than 2%; Electrochemical testing using the Mott-Schottky curve analysis revealed that the free carrier density of the catalytic material was greater than 10. 22 cm -3 ; A method for preparing ternary composite catalytic materials, wherein the method includes the following steps: (1) A mixture A containing bismuth source and acid is mixed with a mixture B containing metavanadate and alkali, and a contact reaction is carried out, wherein the temperature of the contact reaction does not exceed 100°C; (2) The contact reaction product obtained in step (1) is mixed with the titanium source and solvent to carry out a solvothermal reaction; (3) The solvothermal reaction product obtained in step (2) is mixed with the active metal precursor and then calcined under a reducing atmosphere to obtain a ternary composite catalyst.

2. The ternary composite catalytic material according to claim 1, wherein, Both bismuth vanadate and titanium dioxide in the catalytic material contain oxygen vacancies.

3. The ternary composite catalytic material according to claim 2, wherein, The total oxygen vacancy content in the catalytic material is 2-10%.

4. The ternary composite catalytic material according to claim 3, wherein, The total oxygen vacancy content in the catalytic material is 5-8%.

5. The ternary composite catalytic material according to any one of claims 1-4, wherein, Electrochemical testing using the Mott-Schottky curve revealed a free carrier density of 2 × 10⁻⁶. 22 -8×10 22 cm -3 .

6. The ternary composite catalytic material according to claim 5, wherein, Electrochemical testing using the Mott-Schottky curve revealed a free carrier density of 3 × 10⁻⁶. 22 -6×10 22 cm -3 .

7. The ternary composite catalytic material according to any one of claims 1-4, wherein, The active metal is selected from iron and / or cobalt and ruthenium.

8. The ternary composite catalytic material according to any one of claims 1-4, wherein, Based on the total amount of the catalytic material, the content of bismuth vanadate is 20-60 wt%, the content of titanium dioxide is 20-60 wt%, and the content of the active metal (in elemental terms) is 5-20 wt%.

9. The ternary composite catalytic material according to claim 8, wherein, Based on the total amount of the catalytic material, the content of bismuth vanadate is 30-50 wt%, the content of titanium dioxide is 30-50 wt%, and the content of the active metal by element is 8-20 wt%.

10. The ternary composite catalytic material according to claim 9, wherein, The mass ratio of ruthenium to (iron + cobalt) is 0.6-1.5:

1.

11. The method for preparing the ternary composite catalytic material according to claim 1, wherein, The method includes the following steps: (1) A mixture A containing bismuth source and acid is mixed with a mixture B containing metavanadate and alkali, and a contact reaction is carried out, wherein the temperature of the contact reaction does not exceed 100°C; (2) The contact reaction product obtained in step (1) is mixed with the titanium source and solvent to carry out a solvothermal reaction; (3) The solvothermal reaction product obtained in step (2) is mixed with the active metal precursor and then calcined under a reducing atmosphere to obtain a ternary composite catalytic material. The active metal is selected from at least one of iron, ruthenium, nickel, cobalt and copper.

12. The method according to claim 11, wherein, In step (1), the mixture A containing bismuth source and acid is prepared by mixing bismuth source and acid.

13. The method according to claim 11 or 12, wherein, In step (1), the mixture B containing metavanadate and alkali is prepared by mixing metavanadate and alkali.

14. The method according to claim 11 or 12, wherein, In step (1), the molar ratio of the bismuth source (calculated as bismuth element) to the metavanadate (calculated as vanadium element) is 0.5-5:

1.

15. The method according to claim 14, wherein, In step (1), the molar ratio of the bismuth source (calculated as bismuth element) to the metavanadate (calculated as vanadium element) is 0.8-1.2:

1.

16. The method according to claim 11 or 12, wherein, In step (1), H + The molar amount of the acid and OH - The molar amounts of the bases are equal.

17. The method according to claim 11 or 12, wherein, In step (1), the acid is provided by an aqueous solution of the acid, the concentration of which is 0.5-4 mol / L.

18. The method according to claim 17, wherein, In step (1), the acid is provided by an aqueous solution of the acid, the concentration of which is 1-3 mol / L.

19. The method according to claim 11 or 12, wherein, The volume of the aqueous solution of the acid is 200-800 mL relative to 1 mol of the bismuth source (based on bismuth element).

20. The method according to claim 19, wherein, The volume of the aqueous solution of the acid is 350-700 mL relative to 1 mol of the bismuth source (based on bismuth element).

21. The method according to claim 11 or 12, wherein, In step (1), the alkali is provided by an aqueous solution of alkali, the concentration of which is 0.5-4 mol / L.

22. The method according to claim 21, wherein, In step (1), the alkali is provided by an aqueous solution of alkali, the concentration of which is 1-3 mol / L.

23. The method according to claim 11 or 12, wherein, The amount of the aqueous solution of the base used is 200-800 mL relative to 1 mol of the metavanadate based on vanadium element.

24. The method according to claim 23, wherein, The amount of the aqueous solution of the base used is 350-700 mL relative to 1 mol of the metavanadate based on vanadium.

25. The method according to claim 11 or 12, wherein, In step (1), the acid is selected from at least one of nitric acid, sulfuric acid, phosphoric acid, oxalic acid, acetic acid and hydrochloric acid.

26. The method of claim 25, wherein, In step (1), the alkali is an alkali metal hydroxide.

27. The method according to claim 26, wherein, In step (1), the alkali is sodium hydroxide and / or potassium hydroxide.

28. The method according to claim 11 or 12, wherein, In step (1), the bismuth source is a bismuth-containing compound.

29. The method according to claim 28, wherein, In step (1), the bismuth source is selected from at least one of bismuth nitrate, bismuth trichloride and basic bismuth salicylate.

30. The method according to claim 11 or 12, wherein, In step (1), the metavanadate is selected from at least one of sodium metavanadate, potassium metavanadate, and ammonium metavanadate.

31. The method according to claim 11 or 12, wherein, Step (1) includes: adding the mixture A containing bismuth source and acid to the mixture B containing metavanadate and alkali under stirring conditions to carry out a contact reaction.

32. The method according to claim 31, wherein, The addition rate of the mixture containing bismuth source and acid is 0.5-5 mL / min, relative to 10 mL of the mixture B containing metavanadate and alkali.

33. The method according to claim 31, wherein, In step (1), the conditions for the contact reaction include: a temperature of room temperature to 80°C and a time of 0.5 to 24 hours.

34. The method according to claim 11 or 12, wherein, In step (2), the titanium source is a titanium-containing compound.

35. The method according to claim 34, wherein, In step (2), the titanium source is selected from at least one of tetrabutyl titanate, titanium sulfate and titanium tetrachloride.

36. The method according to claim 11 or 12, wherein, In step (2), the solvent is an alcohol.

37. The method of claim 36, wherein, In step (2), the solvent is a monohydric alcohol and / or a polyhydric alcohol.

38. The method according to claim 37, wherein, In step (2), the solvent is at least one of C1-C10 monohydric alcohols, dihydric alcohols, and trihydric alcohols.

39. The method according to claim 38, wherein, In step (2), the solvent is at least one of ethanol, ethylene glycol, n-propanol, isopropanol, 1,2-propanediol, 1,3-propanediol and glycerol.

40. The method according to claim 39, wherein, In step (2), the solvent is at least one of ethanol, isopropanol and glycerol.

41. The method according to claim 11 or 12, wherein, In step (2), the conditions for the solvothermal reaction include: a temperature of 90-200℃ and a time of 12-48h.

42. The method according to claim 11 or 12, wherein, In step (3), the active metal is selected from iron and / or cobalt and ruthenium.

43. The method according to claim 42, wherein, In step (3), the active metal precursor is selected from soluble compounds of various active metals.

44. The method according to claim 43, wherein, In step (3), the active metal precursor is selected from at least one of the nitrate, chloride and sulfate of each active metal.

45. The method according to claim 11 or 12, wherein, In step (3), the mixing is mechanical mixing and / or rotary drying.

46. ​​The method according to claim 45, wherein, In step (3), the mixing is carried out by rotary evaporation and drying.

47. The method according to claim 46, wherein, In step (3), the conditions for rotary drying include a temperature of 70-90℃.

48. The method according to claim 11 or 12, wherein, In step (3), the calcination conditions include: a temperature of 350-600℃, a time of 2-8h, and a heating rate of 2-10℃ / min.

49. The method according to claim 11 or 12, wherein, The flow rate of the reducing atmosphere is 10-80 mL / min.

50. The method according to claim 49, wherein, The flow rate of the reducing atmosphere is 20-60 mL / min.

51. The method according to claim 11 or 12, wherein, The reducing atmosphere includes H2 and an inert gas.

52. The method according to claim 51, wherein, Based on the total volume of the reducing atmosphere, the H2 content is 5-70% by volume.

53. The method according to claim 52, wherein, Based on the total volume of the reducing atmosphere, the H2 content is 10-50% by volume.

54. The application of the ternary composite catalytic material according to any one of claims 1-10 in the photocatalytic ammonia decomposition to produce hydrogen.

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