Supported high-entropy alloy catalyst as well as preparation method and application thereof

Abstract

The invention discloses a supported high-entropy alloy catalyst and a preparation method and application thereof.The catalyst is composed of an Al2O3 carrier and high-entropy alloy nano-particles which are loaded on the Al2O3 carrier and have a single BCC structure phase, high-entropy alloy contains Fe, Co, Ni, In and Zn or / and Cu metal elements, in the catalyst, the high-entropy alloy nano-particles account for 8.3%-49% by mass, and the balance is the high-entropy alloy nano-particles. Wherein the mass percentages of the Fe element, the Co element, the Ni element and the In element in the catalyst are respectively 3-18%, 1-10%, 1-10% and 3-6%, and the mass percentage of the Zn element or / and the Cu element in the catalyst is 0.3-5%. The catalyst provided by the invention has the advantages of simple preparation method, cheap and easily available raw materials, easy realization of large-scale production and the like, and shows excellent catalytic performance and long-time use stability when being used as a catalyst for a reaction of preparing methanol through carbon dioxide hydrogenation.

Description

Technical Field

[0001] This invention relates to a supported high-entropy alloy catalyst, its preparation method, and its application in the CO2 hydrogenation to methanol reaction, belonging to the field of catalyst technology. Background Technology

[0002] Carbon dioxide, as a abundant "carbon resource" in the atmosphere, plays a crucial role in the global carbon cycle. However, the extensive use of traditional fossil fuels by humans over the past century has led to atmospheric carbon dioxide emissions far exceeding the levels that nature can effectively fix through plant photosynthesis and rainwater dissolution. This has resulted in a continuous rise in global atmospheric carbon dioxide concentration, severely disrupting the carbon cycle balance of global ecosystems and threatening sustainable development for humankind.

[0003] In recent years, a series of initiatives aimed at addressing excessive carbon dioxide emissions have been proposed. Among them, carbon dioxide capture and storage (CCS) technology has attracted widespread attention due to the enormous carbon dioxide storage potential of natural storage areas such as depleted oil and gas fields and abandoned coal seams. However, the uncertainty of carbon dioxide storage time and high operating costs have hindered its widespread application. It is worth noting that carbon dioxide is also an abundant and inexpensive carbon resource. How to effectively catalytically convert and utilize carbon dioxide to achieve an "artificial carbon cycle" has become a research hotspot for many scientists.

[0004] Methanol is not only a liquid fuel with excellent combustion performance and easy storage and transportation, but also an important raw material and intermediate for the production of gasoline, aromatics, olefins and other high-value chemicals (such as formaldehyde, acetic acid and dimethyl ether). Therefore, the catalytic conversion of CO2 into methanol is considered the most attractive route for CO2 conversion and utilization. It not only helps to reduce CO2 emissions, but also reduces dependence on foreign oil. Research on the production of methanol by catalytic hydrogenation of CO2 has attracted widespread attention in recent years.

[0005] Existing technologies have reported research on various catalysts for the CO2 hydrogenation to methanol reaction. Currently, commercially available catalysts are mainly copper-based. These catalysts have high CO2 conversion rates but low selectivity for methanol. Furthermore, the increased water production due to the reverse water-gas reaction (RWGS) accelerates catalyst deactivation. Therefore, developing high-performance catalysts is a crucial prerequisite for promoting the industrialization of CO2 hydrogenation to methanol. The applicant previously developed a bulk metal catalyst composed of indium, zinc, nickel, cobalt, and iron and filed an invention patent (application number: 202311574364.6). This bulk metal catalyst contains at least Fe, FeNi, FeCo, and In3Ni2 nanocrystals. Laboratory studies have shown that when this bulk metal catalyst is used in the carbon dioxide hydrogenation to methanol reaction, it not only exhibits high selectivity for the target product methanol and low selectivity for the byproduct methane, but also has a high single-pass conversion rate of carbon dioxide, a wide reaction temperature window, and is particularly suitable for H2-rich feed gas. It also demonstrates good stability (during a 200-hour test, the CO2 conversion rate and methanol selectivity remained stable at different temperatures, showing no signs of deactivation). However, in industrial-scale experiments, it was found that due to the high iron content (70-93.9%) and the presence of elemental Fe phase in the bulk metal catalyst, the amount of methane generated continuously increases during long-term reactions (>300 hours). Furthermore, analysis showed the presence of FeC, which exhibits significant activity for CO2 methanation. x The formation of this phase presents a significant challenge to the industrial application of this bulk metal catalyst.

[0006] High-entropy alloys are complex solid solution alloys composed of four or more alloying elements, with non-equiatomic ratios of the constituent elements and single-phase or multi-phase phase structures. In recent years, they have been attracting increasing attention from researchers in the field of catalysis due to their unique high-entropy structural stability, slow diffusion effect, and cocktail effect (multi-component synergistic catalytic effect). Summary of the Invention

[0007] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a supported high-entropy alloy catalyst, its preparation method, and its application in the CO2 hydrogenation to methanol reaction.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0009] A supported high-entropy alloy catalyst is composed of an Al2O3 support and high-entropy alloy nanoparticles with a single BCC structure supported thereon. The high-entropy alloy contains Fe, Co, Ni, In, and Zn or / and Cu metal elements. In the catalyst, the mass percentage of the high-entropy alloy nanoparticles is 8.3% to 49%, wherein the mass percentages of Fe, Co, Ni, and In in the catalyst are 3% to 18%, 1% to 10%, 1% to 10%, and 3% to 6%, respectively, and the mass percentages of Zn or / and Cu in the catalyst are 0.3% to 5%.

[0010] In one embodiment, the catalyst is composed of an Al2O3 support and FeCoNiInZn high-entropy alloy nanoparticles with a single BCC structure supported thereon. In the catalyst, the FeCoNiInZn high-entropy alloy nanoparticles account for 8.3% to 46.0% by mass, and the mass percentages of iron (Fe), cobalt (Co), nickel (Ni), indium (In), and zinc (Zn) in the catalyst are 3% to 18%, 1% to 10%, 1% to 10%, 3% to 6%, and 0.3% to 2%, respectively.

[0011] In a preferred embodiment, the FeCoNiInZn high-entropy alloy nanoparticles constitute 15.3% to 43.0% of the catalyst by mass, and the Fe element constitutes 5% to 15% of the catalyst by mass, the Co element constitutes 2.5% to 10% of the catalyst by mass, the Ni element constitutes 2.5% to 10% of the catalyst by mass, the In element constitutes 5% to 6% of the catalyst by mass, and the Zn element constitutes 0.3% to 2% of the catalyst by mass.

[0012] In one embodiment, the catalyst is composed of an Al2O3 support and FeCoNiInCu high-entropy alloy nanoparticles with a single BCC structure supported thereon. In the catalyst, the FeCoNiInCu high-entropy alloy nanoparticles account for 9.0% to 49.0% by mass, and the mass percentages of iron (Fe), cobalt (Co), nickel (Ni), indium (In), and copper (Cu) in the catalyst are 3% to 18%, 1% to 10%, 1% to 10%, 3% to 6%, and 1% to 5%, respectively.

[0013] In a preferred embodiment, the FeCoNiInCu high-entropy alloy nanoparticles constitute 19.0% to 36.0% of the catalyst by mass, and the Fe element constitutes 5% to 10% of the catalyst by mass, the Co element constitutes 5% to 10% of the catalyst by mass, the Ni element constitutes 2.5% to 5% of the catalyst by mass, the In element constitutes 5% to 6% of the catalyst by mass, and the Cu element constitutes 1.5% to 5% of the catalyst by mass.

[0014] In one embodiment, the catalyst is composed of an Al2O3 support and FeCoNiInZnCu high-entropy alloy nanoparticles with a single BCC structure supported thereon. In the catalyst, the FeCoNiInZnCu high-entropy alloy nanoparticles account for 18.8% to 48.0% by mass, and the mass percentages of Fe, Co, Ni, In, Zn, and Cu elements in the catalyst are 5% to 15%, Co, 2.5% to 10%, In, 5% to 6%, Zn, and 1% to 5%.

[0015] A method for preparing the supported high-entropy alloy catalyst according to the present invention includes the following steps:

[0016] a) Weigh out the calculated amounts of water-soluble metal salts of Fe, Co, Ni, In and Zn or / and Cu respectively, add them to the amount of deionized water required to wet the Al2O3 support in equal volume, and dissolve them to obtain a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions or / and Cu ions.

[0017] b) Weigh the calculated amount of Al2O3 support and add it to the mixed aqueous solution prepared in step a). Impregnate at room temperature and then dry to obtain the catalyst precursor.

[0018] c) The catalyst precursor obtained in step b) is first calcined in air at 300-400°C for 1-3 hours, and then reduced in hydrogen at 450-550°C for 2-4 hours to obtain the supported high-entropy alloy catalyst.

[0019] In a preferred embodiment, in step a), the water-soluble metal salt is a nitrate or acetate of the respective metal.

[0020] The supported high-entropy alloy catalyst described in this invention can be used as a catalyst for the reaction of carbon dioxide hydrogenation to methanol.

[0021] In one embodiment, the conditions for the carbon dioxide hydrogenation to methanol reaction are as follows: in a fixed bed at 180–300°C and 1–8 MPa pressure, the volume ratio of H2 to CO2 in the feed gas is 3:1–7:1, and the gas hourly space velocity is 12000–24000 mL / (g). cat •h).

[0022] In a preferred embodiment, the conditions for the carbon dioxide hydrogenation to methanol reaction are as follows: in a fixed bed at 210–300°C and 4 MPa pressure, the volume ratio of H2 to CO2 in the feed gas is 5:1, and the gas hourly space velocity is 12000 mL / (g). cat •h).

[0023] Compared with the prior art, the present invention has the following significant advantages:

[0024] 1) The supported high-entropy alloy catalyst provided by this invention has a simple preparation method, uses inexpensive and readily available raw materials, and is easy to scale up for production;

[0025] 2) Experiments show that when the supported high-entropy alloy catalyst provided by this invention is used in the reaction of carbon dioxide hydrogenation to methanol, with a mixture of H2 / CO2 = 5 / 1 (volume / volume) as raw material, it can achieve high efficiency at low reaction temperatures (e.g., 210℃), low pressures (e.g., 4 MPa), and high gas hourly space velocities (e.g., 12000 mL / (g)). cat At a temperature of 10°C, the single-pass conversion rate of carbon dioxide can reach over 10%, and the methanol selectivity can reach over 98%, with the remainder being CO. No methane byproduct is generated. It has excellent catalytic performance with high low-temperature activity and high selectivity for the target product methanol, and can be used as a catalyst for the reaction of carbon dioxide hydrogenation to methanol.

[0026] 3) In particular, the supported high-entropy alloy catalyst provided by the present invention also has excellent stability. It can be used continuously for 500 hours in the reaction of carbon dioxide hydrogenation to methanol without any signs of deactivation. Moreover, the high-entropy alloy in the catalyst still maintains a single BCC structure phase, which has excellent long-term stability and is of great significance for realizing the industrialization of carbon dioxide to methanol. Attached Figure Description

[0027] Figure 1 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInZn-1 / Al2O3) prepared in Example 1;

[0028] Figure 2 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInZn-2 / Al2O3) prepared in Example 2;

[0029] Figure 3This is a transmission electron microscope (TEM) image of the supported high-entropy alloy catalyst (FeCoNiInZn-2 / Al2O3) prepared in Example 2;

[0030] Figure 4 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInZn-3 / Al2O3) prepared in Example 3;

[0031] Figure 5 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInZn-4 / Al2O3) prepared in Example 4;

[0032] Figure 6 The image shows the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInZn-5 / Al2O3) prepared in Example 5.

[0033] Figure 7 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInZn-6 / Al2O3) prepared in Example 6;

[0034] Figure 8 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInCu-1 / Al2O3) prepared in Example 7;

[0035] Figure 9 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInCu-2 / Al2O3) prepared in Example 8;

[0036] Figure 10 This is the XRD pattern of the supported high-entropy alloy catalyst (FeCoNiInZnCu / Al2O3) prepared in Example 9;

[0037] Figure 11 The results are from the stability test of the catalyst FeCoNiInZn-2 / Al2O3 in Application Example 1 after 500 hours of continuous use in the reaction of hydrogenating carbon dioxide to methanol.

[0038] Figure 12 This is the XRD pattern of the catalyst FeCoNiInZn-2 / Al2O3 in Application Example 1 after 500 hours of continuous use in the reaction of hydrogenating carbon dioxide to methanol. Detailed Implementation

[0039] The technical solution of the present invention will be further described in detail and completely below with reference to embodiments, comparative examples, and application examples. Furthermore, experimental methods in the following embodiments, comparative examples, and application examples that do not specify specific conditions generally use common equipment, materials, reagents, etc., which are obtained commercially unless otherwise specified, following conventional conditions, conditions described in the manual, or conditions recommended by the manufacturer. In addition, the raw materials used in the following embodiments, comparative examples, and application examples are all commercially available.

[0040] Example 1

[0041] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In and Zn elements in the catalyst are 15.0%, 5.0%, 2.5%, 3.0% and 0.5% respectively, totaling 26.0% high-entropy alloy and 74.0% Al2O3, calculate and weigh 10.85 grams of ferric nitrate nonahydrate, 2.47 grams of cobalt nitrate hexahydrate, 1.24 grams of nickel nitrate hexahydrate, 1.07 grams of indium nitrate hexahydrate and 0.23 grams of zinc nitrate hexahydrate, dissolve them in 6 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions;

[0042] b) Weigh 7.40 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0043] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and zinc (Zn), denoted as FeCoNiInZn-1 / Al2O3.

[0044] Figure 1 This is the XRD pattern of the FeCoNiInZn-1 / Al2O3 catalyst prepared in this embodiment. Figure 1 As shown, the catalyst prepared in this embodiment is composed of an Al2O3 support and a FeCoNiInZn high-entropy alloy supported thereon, and the FeCoNiInZn high-entropy alloy exhibits a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeCoNiInZn high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 11.2 nanometers using the Scherrer equation.

[0045] Example 2

[0046] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In and Zn elements in the catalyst are 5.0%, 5.0%, 2.5%, 5.0% and 0.5% respectively, totaling 18.0% high-entropy alloy and 82.0% Al2O3, calculate and weigh 3.62 grams of ferric nitrate nonahydrate, 2.47 grams of cobalt nitrate hexahydrate, 1.24 grams of nickel nitrate hexahydrate, 1.78 grams of indium nitrate hexahydrate and 0.23 grams of zinc nitrate hexahydrate, dissolve them in 7 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions;

[0047] b) Weigh 8.20 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0048] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and zinc (Zn), denoted as: FeCoNiInZn-2 / Al2O3.

[0049] Figure 2 This is the XRD pattern of the FeCoNiInZn-2 / Al2O3 catalyst prepared in this embodiment. Figure 2 As shown, the catalyst prepared in this embodiment consists of an Al2O3 support and a FeCoNiInZn high-entropy alloy supported thereon, and the FeCoNiInZn high-entropy alloy exhibits a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeCoNiInZn high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 7.4 nanometers using the Scherrer equation.

[0050] Figure 3 This is a transmission electron microscope (TEM) image of the supported high-entropy alloy catalyst (FeCoNiInZn-2 / Al2O3) prepared in this embodiment. Figure 3 As shown, the size of the loaded FeCoNiInZn high-entropy alloy particles is 6–8 nanometers, which is consistent with the data from the standard. Figure 2 The particle size of the high-entropy alloy calculated using the Scherrer formula from the X-ray diffraction data is consistent.

[0051] Example 3

[0052] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In and Zn elements in the catalyst are 10.0%, 2.5%, 5.0%, 5.0% and 0.5% respectively, the total is: 23.0% high entropy alloy and the balance 77.0% is Al2O3. Calculate and weigh 7.24 grams of ferric nitrate nonahydrate, 1.24 grams of cobalt nitrate hexahydrate, 2.48 grams of nickel nitrate hexahydrate, 1.78 grams of indium nitrate hexahydrate and 0.23 grams of zinc nitrate hexahydrate, dissolve them in 6 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions;

[0053] b) Weigh 7.70 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0054] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and zinc (Zn), denoted as FeCoNiInZn-3 / Al2O3.

[0055] Figure 4 This is the XRD pattern of the FeCoNiInZn-3 / Al2O3 catalyst prepared in this embodiment. Figure 4 As shown, the catalyst prepared in this embodiment is composed of an Al2O3 support and a FeCoNiInZn high-entropy alloy supported thereon, and the FeCoNiInZn high-entropy alloy exhibits a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeCoNiInZn pentagonal high-entropy alloy, the particle size of the pentagonal high-entropy alloy supported on the Al2O3 support is calculated to be 10.8 nanometers using the Scherrer equation.

[0056] Example 4

[0057] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In and Zn elements in the catalyst are 5.0%, 10.0%, 5.0%, 6.0% and 0.3% respectively, the total is: 26.3% high entropy alloy and the balance 73.7% is Al2O3. Weigh out 3.62 grams of ferric nitrate nonahydrate, 4.94 grams of cobalt nitrate hexahydrate, 2.48 grams of nickel nitrate hexahydrate, 2.14 grams of indium nitrate hexahydrate and 0.14 grams of zinc nitrate hexahydrate, dissolve them in 6 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions;

[0058] b) Weigh 7.37 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0059] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and zinc (Zn), denoted as FeCoNiInZn-4 / Al2O3.

[0060] Figure 5 This is the XRD pattern of the FeCoNiInZn-4 / Al2O3 catalyst prepared in this embodiment. Figure 5 As shown, the catalyst prepared in this embodiment consists of an Al2O3 support and a FeCoNiInZn high-entropy alloy supported thereon, and the FeCoNiInZn high-entropy alloy exhibits a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeCoNiInZn high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 8.2 nanometers using the Scherrer equation.

[0061] Example 5

[0062] a) Based on the preparation of 10 grams of catalyst, and according to the theoretical mass contents of Fe, Co, Ni, In and Zn elements in the catalyst being 15.0%, 10.0%, 10.0%, 6.0% and 1.0% respectively, totaling 42.0% high-entropy alloy and 58.0% Al2O3, 10.85 grams of ferric nitrate nonahydrate, 4.94 grams of cobalt nitrate hexahydrate, 4.96 grams of nickel nitrate hexahydrate, 2.14 grams of indium nitrate hexahydrate and 0.46 grams of zinc nitrate hexahydrate were weighed and dissolved in 5 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions;

[0063] b) Weigh 5.80 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0064] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and zinc (Zn), denoted as FeCoNiInZn-5 / Al2O3.

[0065] Figure 6 This is the XRD pattern of the FeCoNiInZn-5 / Al2O3 catalyst prepared in this embodiment. Figure 6 As shown, the catalyst prepared in this embodiment is composed of an Al2O3 support and a FeCoNiInZn high-entropy alloy supported thereon, and the FeCoNiInZn high-entropy alloy exhibits a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeCoNiInZn high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 13.1 nanometers using the Scherrer equation.

[0066] Example 6

[0067] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In and Zn elements in the catalyst are 10.0%, 5.0%, 2.5%, 5.0% and 2.0% respectively, totaling 24.5% high-entropy alloy and 75.5% Al2O3, calculate and weigh 7.23 grams of ferric nitrate nonahydrate, 2.47 grams of cobalt nitrate hexahydrate, 1.24 grams of nickel nitrate hexahydrate, 1.78 grams of indium nitrate hexahydrate and 0.92 grams of zinc nitrate hexahydrate, dissolve them in 6.5 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions;

[0068] b) Weigh 7.55 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0069] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and zinc (Zn), denoted as FeCoNiInZn-6 / Al2O3.

[0070] Figure 7 This is the XRD pattern of the FeCoNiInZn-6 / Al2O3 catalyst prepared in this embodiment. Figure 7As shown, the catalyst prepared in this embodiment is composed of an Al2O3 support and a FeCoNiInZn high-entropy alloy supported thereon, and the FeCoNiInZn high-entropy alloy exhibits a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeCoNiInZn high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 11.9 nanometers using the Scherrer equation.

[0071] Example 7

[0072] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In and Cu elements in the catalyst are 10.0%, 5.0%, 2.5%, 5.0% and 1.5% respectively, totaling 29.0% high-entropy alloy and 71.0% Al2O3, calculate and weigh 7.24 grams of ferric nitrate nonahydrate, 2.47 grams of cobalt nitrate hexahydrate, 1.24 grams of nickel nitrate hexahydrate, 1.78 grams of indium nitrate hexahydrate and 0.70 grams of copper nitrate hexahydrate, dissolve them in 6.1 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Cu ions;

[0073] b) Weigh 7.10 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Cu ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0074] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and copper (Cu), denoted as FeCoNiInCu-1 / Al2O3.

[0075] Figure 8 This is the XRD pattern of the FeCoNiInCu-1 / Al2O3 catalyst prepared in this embodiment. Figure 8 As shown, the catalyst prepared in this embodiment is composed of an Al2O3 support and a FeCoNiInCu high-entropy alloy supported thereon, and the FeCoNiInCu high-entropy alloy exhibits a single BCC structure phase; based on the strongest X-ray diffraction peak of the FeCoNiInCu high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 9.1 nanometers using the Scherrer equation.

[0076] Example 8

[0077] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In and Cu elements in the catalyst are 5.0%, 10.0%, 5.0%, 5.0% and 5.0% respectively, totaling 30.0% high-entropy alloy and 70.0% Al2O3, calculate and weigh 3.62 grams of ferric nitrate nonahydrate, 4.94 grams of cobalt nitrate hexahydrate, 2.48 grams of nickel nitrate hexahydrate, 1.78 grams of indium nitrate hexahydrate and 2.33 grams of copper nitrate hexahydrate, dissolve them in 6.0 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Cu ions;

[0078] b) Weigh 7.00 g of Al2O3 support (in this example, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Cu ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0079] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In) and copper (Cu), denoted as: FeCoNiInCu-2 / Al2O3.

[0080] Figure 9 This is the XRD pattern of the FeCoNiInCu-2 / Al2O3 catalyst prepared in this embodiment. Figure 9 As shown, the catalyst prepared in this embodiment is composed of an Al2O3 support and a FeCoNiInCu high-entropy alloy supported thereon, and the FeCoNiInCu high-entropy alloy exhibits a single BCC structure phase; based on the strongest X-ray diffraction peak of the FeCoNiInCu high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 8.3 nanometers using the Scherrer equation.

[0081] Example 9

[0082] a) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni, In, Zn and Cu elements in the catalyst are 5.0%, 5.0%, 2.5%, 5.0%, 0.5% and 1.5% respectively, totaling 19.5% high-entropy alloy and 80.5% Al2O3, calculate and weigh 3.62 grams of ferric nitrate nonahydrate, 2.47 grams of cobalt nitrate hexahydrate, 1.24 grams of nickel nitrate hexahydrate, 1.78 grams of indium nitrate hexahydrate, 0.23 grams of zinc nitrate hexahydrate and 0.70 grams of copper nitrate hexahydrate, dissolve them in 6.9 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions, Zn ions and Cu ions;

[0083] b) Weigh 8.05 g of Al2O3 support (in this embodiment, Aladdin brand γ-Al2O3 support is used) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions, Zn ions and Cu ions prepared in step a). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0084] c) The catalyst precursor obtained in step b) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni), indium (In), zinc (Zn) and copper (Cu), denoted as: FeCoNiInZnCu / Al2O3.

[0085] Figure 10 This is the XRD pattern of the FeCoNiInZnCu / Al2O3 catalyst prepared in this embodiment. Figure 10 As shown, the catalyst prepared in this embodiment consists of an Al2O3 support and a FeCoNiInZnCu high-entropy alloy supported thereon, and the FeCoNiInZnCu high-entropy alloy exhibits a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeCoNiInZnCu high-entropy alloy, the particle size of the high-entropy alloy supported on the Al2O3 support is calculated to be 7.6 nanometers using the Scherrer equation.

[0086] Comparative Example 1

[0087] 1) Based on the preparation of 10 grams of catalyst, and assuming the theoretical mass contents of Fe, Co, Ni and In elements in the catalyst are 5.0%, 5.0%, 2.5% and 5.0% respectively, the total is 17.5% quaternary high entropy alloy and the balance is 82.5% Al2O3. Weigh out 3.62 grams of ferric nitrate nonahydrate, 2.47 grams of cobalt nitrate hexahydrate, 1.24 grams of nickel nitrate hexahydrate and 1.78 grams of indium nitrate hexahydrate, dissolve them in 7 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions, Ni ions and In ions;

[0088] 2) Weigh 8.25 g of γ-Al2O3 support (Aladdin brand) and add it to the mixed aqueous solution containing Fe ions, Co ions, Ni ions and In ions prepared in step 1). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0089] 3) The catalyst precursor obtained in step 2) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported quaternary high-entropy alloy catalyst containing iron (Fe), cobalt (Co), nickel (Ni) and indium (In), denoted as FeCoNiIn / Al2O3.

[0090] Comparative Example 2

[0091] 1) Based on the preparation of 10 grams of catalyst, and according to the theoretical mass contents of Fe, Co and Ni elements in the catalyst being 5%, 5% and 2.5% respectively, the total ternary alloy is 12.5%, and the balance is 87.5% Al2O3. Calculate and weigh 3.62 grams of ferric nitrate nonahydrate, 2.47 grams of cobalt nitrate hexahydrate and 1.24 grams of nickel nitrate hexahydrate, dissolve them in 7 ml of distilled water to prepare a mixed aqueous solution containing Fe ions, Co ions and Ni ions;

[0092] 2) Weigh 8.75 g of γ-Al2O3 support (Aladdin brand) and add it to the mixed aqueous solution containing Fe ions, Co ions and Ni ions prepared in step 1). Stir at room temperature to make it impregnated evenly (about 5 to 6 hours), and then dry at 100°C to obtain the catalyst precursor.

[0093] 3) The catalyst precursor obtained in step 2) is first calcined in air at 350°C for 2 hours, and then reduced in hydrogen at 500°C for 3 hours to obtain an Al2O3-supported ternary alloy catalyst containing iron (Fe), cobalt (Co) and nickel (Ni), denoted as FeCoNi / Al2O3.

[0094] Application Example 1

[0095] In a fixed-bed reactor, the supported high-entropy alloy catalyst FeCoNiInZn-2 / Al2O3 prepared in Example 2 was used to investigate the catalytic performance of carbon dioxide hydrogenation to methanol under different reaction conditions:

[0096] A stainless steel fixed-bed reactor with an aluminum liner is used, with the catalyst packed in the aluminum liner, which has an outer diameter of 10 mm, an inner diameter of 8 mm, and a length of 770 mm. The reaction products are quantitatively detected and analyzed online by a gas chromatograph equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD). The supported high-entropy alloy catalyst is directly tested for performance under the set reaction conditions without further activation treatment.

[0097] Reaction conditions 1: Reaction temperature 180–300℃, reaction pressure 4 MPa, H2:CO2 ratio in the feed gas = 5:1 (volume ratio), catalyst dosage 0.50 g, gas hourly space velocity 12000 mL / (g) cat •h) (i.e., CO2 hourly space velocity is 2000 mL / (g) cat •h));

[0098] The effect of reaction temperature on catalytic performance was investigated under the above conditions, and the results are shown in Table 1.

[0099] Table 1 Catalytic performance of carbon dioxide hydrogenation to methanol at different reaction temperatures

[0100] Reaction temperature (°C) <![CDATA[CO2 conversion rate (%)]]> <![CDATA[CH3OH selectivity (%)]]> CO selectivity (%) <![CDATA[CH4 Selectivity (%)]]> 180 5.1 99.1 0.9 0.0 190 6.5 98.7 1.3 0.0 200 7.6 98.5 1.5 0.0 210 10.5 98.2 1.8 0.0 230 12.2 97.5 2.5 0.0 250 13.4 96.5 3.5 0.0 260 15.7 94.4 5.6 0.0 270 17.3 91.6 8.4 0.0 300 22.5 84.1 15.9 0.0

[0101] As shown in Table 1, under the same conditions, increasing the temperature is beneficial to improving the single-pass conversion rate of carbon dioxide, but it will reduce the selectivity of methanol and gradually increase the CO byproducts. However, no methane byproducts are generated in the range of 180 to 300°C.

[0102] Reaction conditions 2: Reaction temperature 250℃, reaction pressure 4 MPa, catalyst dosage 0.50 g, CO2 gas hourly space velocity 0.50 mL / (g) cat •h);

[0103] The effect of the volume ratio of H2 / CO2 in the feed gas on the catalytic performance was investigated under the above conditions. The reaction results are shown in Table 2.

[0104] Table 2 Catalytic performance of different H2 / CO2 volume ratios on the hydrogenation of carbon dioxide to methanol

[0105] <![CDATA[H2 / CO2]]> <![CDATA[CO2 conversion rate (%)]]> <![CDATA[CH3OH selectivity (%)]]> CO selectivity (%) <![CDATA[CH4 Selectivity (%)]]> 3:1 11.7 95.3 4.7 0.0 5:1 13.4 96.5 3.5 0.0 7:1 18.5 97.5 2.5 0.0

[0106] As shown in Table 2, under the same conditions, a higher H2 / CO2 volume ratio is more conducive to improving the single-pass conversion rate of carbon dioxide and the selectivity of methanol, and can simultaneously reduce CO byproducts. Furthermore, no methane byproducts are generated within the H2 / CO2 volume ratio range of 3:1 to 7:1. This indicates that the supported high-entropy alloy catalyst described in this invention has excellent catalytic performance for the hydrogenation of carbon dioxide to methanol from H2-rich feed gas.

[0107] Reaction conditions 3: Reaction temperature was 250℃, the ratio of H2 to CO2 in the feed gas was 5:1 (volume ratio), the catalyst dosage was 0.50 g, and the gas hourly space velocity was mL / (g). cat •h) (i.e., CO2 hourly space velocity is mL / (g) cat •h));

[0108] The effect of reaction pressure on catalytic performance was investigated under the above conditions, and the results are shown in Table 3.

[0109] Table 3 Catalytic performance of carbon dioxide hydrogenation to methanol under different reaction pressures

[0110] Pressure (MPa) <![CDATA[CO2 conversion rate (%)]]> <![CDATA[CH3OH selectivity (%)]]> CO selectivity (%) <![CDATA[CH4 Selectivity (%)]]> 1 6.9 91.2 8.8 0.0 4 13.4 96.5 3.5 0.0 6 15.6 95.2 4.8 0.0 8 18.5 94.5 3.5 0.0

[0111] As shown in Table 3, under the same conditions, increasing the reaction pressure will help improve the single-pass conversion rate of carbon dioxide. However, for the selectivity of methanol, the optimal pressure is 4-8 MPa. If the reaction pressure is less than 4 MPa, both the single-pass conversion rate of carbon dioxide and the selectivity of methanol will decrease. However, no methane byproducts are generated when the reaction pressure is in the range of 1-8 MPa.

[0112] Reaction conditions 4: reaction temperature is 250℃, reaction pressure is 4 MPa, H2:CO2 ratio in the feed gas is 5:1 (volume ratio), and catalyst dosage is 0.50 g;

[0113] The effect of gas hourly space velocity on catalytic performance was investigated under the above conditions, and the reaction results are shown in Table 4.

[0114] Table 4 Catalytic performance of different gas hour space velocities on the hydrogenation of carbon dioxide to methanol

[0115] <![CDATA[Gas hourly space velocity (mL / (g cat •h))]]> <![CDATA[CO2 conversion rate (%)]]> <![CDATA[CH3OH selectivity (%)]]> CO selectivity (%) <![CDATA[CH4 Selectivity (%)]]> 12000 13.4 96.5 3.5 0.0 18000 13.1 96.2 4.2 0.0 24000 12.7 96.0 4.0 0.0

[0116] As shown in Table 4, under the same conditions, increasing the gas hourly space velocity (GHSV) will decrease the single-pass conversion of carbon dioxide and the selectivity of methanol. However, when the GHSV is between 12000 and 24000 mL / (g) cat Within the range of •h), no methane byproducts were generated.

[0117] In addition, under the conditions of a reaction temperature of 210–300 °C, a reaction pressure of 4 MPa, a H2:CO2 ratio of 5:1 (volume ratio) in the feed gas, a catalyst dosage of 0.50 g, and a gas hourly space velocity of 12000 mL / (g) cat Under the condition of •h), the stability of the catalytic performance of the supported high-entropy alloy catalyst prepared in Example 2 in the reaction of carbon dioxide hydrogenation to methanol was investigated.

[0118] Figure 11 These are the stability test results of the catalyst FeCoNiInZn-2 / Al2O3 in Example 2 during the hydrogenation of carbon dioxide to methanol. Figure 11 As shown, within a wide temperature range of 210–300 °C, the catalyst FeCoNiInZn-2 / Al2O3 in Example 2 can be used continuously for 500 hours. It can also achieve a single-pass CO2 conversion rate of nearly 16% and a methanol selectivity of nearly 95% at 260 °C, without the generation of methane. It has excellent long-term stability and is very beneficial for industrial applications.

[0119] Figure 12 This is the XRD pattern of the catalyst FeCoNiInZn-2 / Al2O3 from Example 2 after 500 hours of continuous use in the carbon dioxide hydrogenation to methanol reaction. Figure 12 As shown, the FeCoNiInZn high-entropy alloy on the catalyst FeCoNiInZn-2 / Al2O3 in Example 2 of this invention still maintains a single BCC structure phase. Based on the strongest X-ray diffraction peak of the FeNiInCo quaternary high-entropy alloy, the Scherrer equation shows that the quaternary high-entropy alloy particles did not undergo sintering growth after a 500-hour stability reaction test, and the particle size was 7.2 nanometers (comparable to that before the reaction). This demonstrates excellent phase structure and anti-sintering stability, which is of great significance for realizing industrial applications.

[0120] Application Example 2

[0121] The catalytic performance of the catalysts in Examples 1-9 and Comparative Examples 1-2 for the hydrogenation of carbon dioxide to methanol was investigated in a fixed-bed reactor.

[0122] A stainless steel fixed-bed reactor with an aluminum liner is used, in which the catalyst is filled. The liner has an outer diameter of 10 mm, an inner diameter of 8 mm, and a length of 770 mm. The reaction products are quantitatively detected and analyzed online by a gas chromatograph equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD). The catalysts are directly tested for performance under the set reaction conditions without further activation treatment.

[0123] Reaction conditions: reaction temperature 250℃, reaction pressure 4 MPa, H2:CO2 ratio in the feed gas = 5:1 (volume ratio), catalyst dosage 0.50 g, gas hourly space velocity 12000 mL / (g) cat •h) (i.e., CO2 hourly space velocity is 2000 mL / (g) cat •h)).

[0124] Under the above reaction conditions, the catalytic performance of each catalyst for the hydrogenation of carbon dioxide to methanol is detailed in Table 5.

[0125] Table 5 Catalytic performance of various catalysts for the hydrogenation of carbon dioxide to methanol

[0126] catalyst <![CDATA[CO2 conversion rate (%)]]> <![CDATA[CH3OH selectivity (%)]]> CO selectivity (%) <![CDATA[CH4 selectivity (%)]]> Example 1 12.5 94.3 5.7 0.0 Example 2 13.4 96.5 3.5 0.0 Example 3 12.3 95.6 4.4 0.0 Example 4 13.0 93.9 6.1 0.0 Example 5 13.1 91.9 8.1 0.0 Example 6 12.8 92.1 7.9 0.0 Example 7 12.7 94.6 5.4 0.0 Example 8 11.5 95.8 4.2 0.0 Example 9 13.2 96.5 3.5 0.0 Comparative Example 1 10.7 92.1 7.9 0.0 Comparative Example 2 17.3 16.7 6.7 69.5

[0127] As shown in Table 5, the supported high-entropy alloy catalyst of this invention exhibits excellent catalytic activity and high selectivity for methanol when used in the carbon dioxide hydrogenation to methanol reaction. Under the stated reaction conditions, no methane byproduct is generated. Comparison of Example 2 with Comparative Example 1 and Example 7 with Comparative Example 1 shows that, under the same reaction conditions and with the same content of Fe, Co, Ni, and In elements, the FeCoNiInZn and FeCoNiInCu high-entropy alloys of this invention significantly improve the single-pass conversion rate of CO2 and the selectivity for methanol compared to the quaternary high-entropy alloy FeCoNiIn, while maintaining the absence of methane byproduct formation. Furthermore, the supported high-entropy alloy catalyst of this invention also has advantages such as simple preparation method, inexpensive and readily available raw materials, ease of large-scale production, and good stability. Therefore, this invention has significant industrial application value and is of great importance for the industrialization of carbon dioxide to methanol production.

[0128] Finally, it should be noted that the above are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention are within the scope of protection of the present invention. For example, the metal nitrates used in the above embodiments can be replaced with metal acetates. The calcination temperature of the catalyst precursor in the above embodiments in an air atmosphere can be replaced by a temperature within the range of 300-400°C (inclusive), and the corresponding calcination time can be replaced by a time within the range of 1-3 hours (inclusive), but the higher the calcination temperature, the shorter the calcination time. Similarly, the reduction temperature of the catalyst precursor in a hydrogen atmosphere in the above embodiments can be replaced by a temperature within the range of 450-550°C (inclusive), and the corresponding reduction time can be replaced by a time within the range of 2-4 hours (inclusive), but the higher the reduction temperature, the shorter the reduction time.

Claims

1. A supported high-entropy alloy catalyst, comprising an Al2O3 support and high-entropy alloy nanoparticles with a single BCC structure supported thereon; characterized in that: The high-entropy alloy contains Fe, Co, Ni, In and Zn or / and Cu metal elements. In the catalyst, the mass percentage of the high-entropy alloy nanoparticles is 8.3% to 49%, wherein the mass percentages of Fe, Co, Ni and In elements in the catalyst are 3% to 18%, 1% to 10%, 1% to 10% and 3% to 6%, respectively, and the mass percentages of Zn or / and Cu elements in the catalyst are 0.3% to 5%.

2. The supported high-entropy alloy catalyst according to claim 1, characterized in that: The catalyst is composed of an Al2O3 support and FeCoNiInZn high-entropy alloy nanoparticles with a single BCC structure supported thereon. In the catalyst, the mass percentage of FeCoNiInZn high-entropy alloy nanoparticles is 8.3% to 46.0%, and the mass percentage of Fe in the catalyst is 3% to 18%, the mass percentage of Co in the catalyst is 1% to 10%, the mass percentage of Ni in the catalyst is 1% to 10%, the mass percentage of In in the catalyst is 3% to 6%, and the mass percentage of Zn in the catalyst is 0.3% to 2%.

3. The supported high-entropy alloy catalyst according to claim 2, characterized in that: In the catalyst, the mass percentage of FeCoNiInZn high-entropy alloy nanoparticles is 15.3% to 43.0%, and the mass percentage of Fe element in the catalyst is 5% to 15%, the mass percentage of Co element in the catalyst is 2.5% to 10%, the mass percentage of Ni element in the catalyst is 2.5% to 10%, the mass percentage of In element in the catalyst is 5% to 6%, and the mass percentage of Zn element in the catalyst is 0.3% to 2%.

4. The supported high-entropy alloy catalyst according to claim 1, characterized in that: The catalyst is composed of an Al2O3 support and FeCoNiInCu high-entropy alloy nanoparticles with a single BCC structure supported thereon. In the catalyst, the mass percentage of FeCoNiInCu high-entropy alloy nanoparticles is 9.0% to 49.0%, and the mass percentage of Fe element in the catalyst is 3% to 18%, the mass percentage of Co element in the catalyst is 1% to 10%, the mass percentage of Ni element in the catalyst is 1% to 10%, the mass percentage of In element in the catalyst is 3% to 6%, and the mass percentage of Cu element in the catalyst is 1% to 5%.

5. The supported high-entropy alloy catalyst according to claim 4, characterized in that: In the catalyst, the mass percentage of FeCoNiInCu high-entropy alloy nanoparticles is 19.0% to 36.0%, and the mass percentage of Fe, Co, Ni, In, and Cu in the catalyst is 5% to 10%, 5% to 10%, 2.5% to 5%, 5% to 6%, and 1.5% to 5%.

6. The supported high-entropy alloy catalyst according to claim 1, characterized in that: The catalyst is composed of an Al2O3 support and FeCoNiInZnCu high-entropy alloy nanoparticles with a single BCC structure supported thereon. In the catalyst, the mass percentage of FeCoNiInZnCu high-entropy alloy nanoparticles is 18.8% to 48.0%, and the mass percentage of Fe in the catalyst is 5% to 15%, the mass percentage of Co in the catalyst is 5% to 10%, the mass percentage of Ni in the catalyst is 2.5% to 10%, the mass percentage of In in the catalyst is 5% to 6%, the mass percentage of Zn in the catalyst is 0.3% to 2%, and the mass percentage of Cu in the catalyst is 1% to 5%.

7. A method for preparing the supported high-entropy alloy catalyst according to claim 1, characterized in that, The preparation method includes the following steps: a) Weigh out the calculated amounts of water-soluble metal salts of Fe, Co, Ni, In and Zn or / and Cu respectively, add them to the amount of deionized water required to wet the Al2O3 support in equal volume, and dissolve them to obtain a mixed aqueous solution containing Fe ions, Co ions, Ni ions, In ions and Zn ions or / and Cu ions. b) Weigh the calculated amount of Al2O3 support and add it to the mixed aqueous solution prepared in step a). Impregnate at room temperature and then dry to obtain the catalyst precursor. c) The catalyst precursor obtained in step b) is first calcined in air at 300-400°C for 1-3 hours, and then reduced in hydrogen at 450-550°C for 2-4 hours to obtain the supported high-entropy alloy catalyst.

8. The preparation method according to claim 7, characterized in that: In step a), the water-soluble metal salt is a nitrate or acetate of the respective metal.

9. The application of the supported high-entropy alloy catalyst according to claim 1, characterized in that: It is used as a catalyst in the hydrogenation of carbon dioxide to methanol.

10. The application according to claim 9, characterized in that, The conditions for the carbon dioxide hydrogenation to methanol reaction are as follows: in a fixed bed at 180–300°C and 1–8 MPa, the volume ratio of H2 to CO2 in the feed gas is 3:1–7:1, and the gas hourly space velocity is 12000–24000 mL / (g). cat •h).

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