Method for synthesizing high-entropy alloy nano-catalyst, catalyst and application thereof

Abstract

The present invention relates to a high-entropy alloy catalyst and the application of such a catalyst in methane combustion. This method uses a reducible metal oxide as a carrier and a high-entropy alloy as the active phase, and the synthesis temperature does not exceed 600 °C. After synthesizing the catalyst, it is used for methane combustion. The reaction process is as follows: The catalyst is mixed with quartz sand and formed into catalyst particles, which are then added to a fixed bed. Methane combustion reaction is carried out by heating in a mixed gas stream of CH4, O2, and N2. The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation, etc.

Description

Technical Field

[0001] The present invention relates to a method for in-situ synthesizing a high-entropy alloy nanocatalyst on a reducible oxide support under mild conditions, and specifically relates to the application of this type of catalyst in the methane combustion reaction. Background Art

[0002] The world today faces the difficulties of excessive emissions of air pollutants and extreme global climate change. The world's energy structure is undergoing a transformation from fossil energy to renewable energy. The methane combustion reaction has the advantages of clean products and high heat release. Multiple research groups have conducted research on this (Angewandte Chemie International Edition 59, 18522 - 18526, (2020); Nature Catalysis 4, 62 - 70, (2021); ACS Catalysis 10, 1381 - 1387, (2020)). The focus of related research is to improve the conversion rate of methane combustion. Therefore, a series of noble metal catalysts have been developed. Noble metal alloy catalysts have attracted great attention from experts in the field due to their outstanding dual-component synergistic effect, which greatly improves the catalytic activity and catalyst life. However, noble metal alloy catalysts also have defects such as high cost and limited mutual solubility. Therefore, it is of great significance to develop a high-entropy alloy catalyst composed of noble metals and transition metals. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of extremely short heating time, extremely high temperature, and extremely fast cooling rate required in the preparation process of high-entropy alloys.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A method for in-situ synthesizing a high-entropy alloy nanocatalyst on a reducible oxide support under mild conditions:

[0006] Impregnate Pt, Pd, Ni, Co, Fe on the surface of TiO2 - anatase, heat to 400 °C and maintain for 10 min, rapidly cool with liquid nitrogen, wait for the liquid nitrogen to evaporate and then naturally warm up to room temperature, and finally reduce at 600 °C under 30 mL / min H2 for 2 h.

[0007] Provide a solution:

[0008] The support of the high-entropy alloy active phase can be TiO2 - anatase, CeO2, ZrO2, In2O3, Fe2O3, Nb2O5, MoO3, SnO2, Ga2O3, PrO2.

[0009] Provide a solution:

[0010] The inert atmosphere for methane combustion includes one of N2, Ar, and He

[0011] The inert gas accounts for 50% - 90% of the total gas

[0012] The methane space velocity on the catalyst is 5000 - 40000 ml / (g cat ·h).

[0013] The beneficial effects of the present invention are as follows:

[0014] The conditions for preparing the high-entropy alloy in the present invention are significantly lower than those reported in previous literature (Science 359, 1489 - 1494, (2018)), and the high-entropy alloy nanocatalyst can be synthesized on an oxide support without electrical conductivity. Description of the Drawings

[0015] Figure 1 Electron microscopy images of in-situ synthesized high-entropy alloy nanocatalysts on reducible oxide supports under mild conditions. a) PtPdCoFe / TiO2 - Anatase, corresponding to Example 2; b) PtPdCoFe / TiO2 - Rutile, corresponding to Example 33; c) PtPdCoFe / SiO2, corresponding to Example 34. Detailed Embodiments

[0016] To illustrate the present invention in detail, several specific embodiments are given below, but the present invention is not limited to these embodiments.

[0017] Example 1

[0018] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 are added to 100 mL of aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1 mmol. Then, the reducible oxide carrier TiO2-antase is added to the suspension (the mass of the added carrier is calculated based on the total loading of 0.5 wt% of the active phase metal elements in the catalyst product), stirred for 2 hours, and the solvent is evaporated at 120°C, heated to about 400°C and kept for about 10 minutes. The resulting hot solid is poured into liquid nitrogen and quenched to the boiling point of liquid nitrogen (about -196°C), taken out and naturally heated to room temperature, and then reduced at 600°C, 30 mL / min H2 for 2 hours. The total loading of PtPdNiCoFe is 0.5wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was evenly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst was synthesized, it was used for methane combustion at 400°C. The reaction process is as follows: 100mg PtPdNiCoFe / TiO2 was mixed with 2g quartz sand and formed into 40-60 mesh particles and added to a fixed bed. The methane combustion reaction was heated to 400°C in a 30ml / min airflow of 0.5vol% CH4, 10vol% O2, and 89.5vol% N2. The space velocity is 20000ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0019] Example 2

[0020] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0021] Example 3

[0022] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 5wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 5wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400oC. The reaction process is as follows: 100mg PtPdNiCoFe / TiO2 is mixed with 2g quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400℃ in a 30ml / min air flow of 0.5vol% CH4, 10vol% O2, and 89.5vol% N2. The air velocity is 20000ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0023] Example 4

[0024] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 2:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0025] Example 5

[0026] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:2:1:1:1. Then, the reducible oxide carrier TiO2-anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, and then taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400oC. The reaction process is as follows: 100mg PtPdNiCoFe / TiO2 is mixed with 2g quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400℃ in a 30ml / min air flow of 0.5vol% CH4, 10vol% O2, and 89.5vol% N2. The air velocity is 20000ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0027] Example 6

[0028] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:2:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, and then taken out and reduced at 600 °C under 30 mL / min H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0029] Example 7

[0030] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:2:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced at 600 °C under 30 mL / min H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0031] Example 8

[0032] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:2 with a total molar amount of 0.1 mmol. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0033] Example 9

[0034] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, reducible oxide support ZrO2 was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / ZrO2 was mixed with 2 g of quartz sand and formed into particles of 40-60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0035] Example 10

[0036] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, and then the reducible oxide carrier In2O3 was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, and then taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst was synthesized, it was used for methane combustion at 400℃. The reaction process is as follows: 100 mg PtPdNiCoFe / In2O3 is mixed with 2 g quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is carried out by heating to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0037] Embodiment 11

[0038] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, and then the reducible oxide carrier CeO2 was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, and then taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst was synthesized, it was used for methane combustion at 400℃. The reaction process is as follows: 100 mg PtPdNiCoFe / CeO2 is mixed with 2 g quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is carried out by heating to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0039] Example 12

[0040] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support Ga2O3 was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, then quenched to the boiling point of liquid nitrogen, -196 °C, with liquid nitrogen. After being taken out, it was reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / Ga2O3 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0041] Example 13

[0042] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution according to the molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1 with a total molar amount of 0.1 mmol. Then, the reducible oxide support Fe2O3 was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced at 600 °C under 30 mL / min H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the synthesis of the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / Fe2O3 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0043] Example 14

[0044] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, and then the reducible oxide carrier Nb2O5 was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, and then taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles, and the size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst was synthesized, it was used for methane combustion at 400℃. The reaction process is as follows: 100 mg PtPdNiCoFe / Nb2O5 is mixed with 2 g quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The mixture is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2 to carry out a methane combustion reaction. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0045] Embodiment 15

[0046] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, reducible oxide support MoO3 was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, then quenched with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced at 600 °C under 30 mL / min H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / MoO3 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0047] Example 16

[0048] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, and then the reducible oxide carrier PrO2 was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, and then taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst was synthesized, it was used for methane combustion at 400℃. The reaction process is as follows: 100 mg PtPdNiCoFe / PrO2 is mixed with 2 g quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The mixture is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2 to carry out a methane combustion reaction. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0049] Embodiment 17

[0050] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400°C. The reaction process is as follows: 100 mg of PtPdNiCoFe / TiO2 is mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% He. The space velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0051] Embodiment 18

[0052] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400°C. The reaction process is as follows: 100 mg of PtPdNiCoFe / TiO2 is mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% Ar. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0053] Embodiment 19

[0054] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out, and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 5000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0055] Example 20

[0056] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to the total metal loading of 1 wt% in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into particles of 40-60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 40000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0057] Example 21

[0058] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2 - anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen - 196 °C, and then taken out and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO - FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high - entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP - OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40 - 60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 2 vol% CH4, 40 vol% O2, and 58 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high - entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0059] Example 22

[0060] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 2.5 vol% O2, and 97 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0061] Example 23

[0062] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol at a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to the total metal loading of 1 wt% in the catalyst product). It was heated for 10 min to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced at 600 °C under 30 mL / min H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the synthesis of the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 7.5 vol% O2, and 92 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0063] Example 24

[0064] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol at a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 300 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into particles of 40-60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out by heating to 300 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0065] Example 25

[0066] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 800°C. The reaction process is as follows: 100 mg of PtPdNiCoFe / TiO2 is mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 800°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0067] Embodiment 26

[0068] H2PtCl6, Pd(NO3)2, Zn(NO3)2, Cu(NO3)2, and Zr(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Zn:Cu:Zr = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to the total metal loading of 1 wt% in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdZnCuZr was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdZnCuZr / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0069] Example 27

[0070] H2AuCl4, Pd(NO3)2, Ir(NO3)2, Mn(NO3)2, and Cr(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Au:Pd:Ir:Mn:Cr = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of AuPdIrMnCr was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of AuPdIrMnCr / TiO2 was mixed with 2 g of quartz sand and formed into particles of 40-60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0071] Example 28

[0072] H2AuCl4, Pd(NO3)2, VCl3, Mn(NO3)2, and Cr(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Au:Pd:V:Mn:Cr = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of AuPdVMnCr was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of AuPdVMnCr / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0073] Example 29

[0074] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 300℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400°C. The reaction process is as follows: 100 mg of PtPdNiCoFe / TiO2 is mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0075] Embodiment 30

[0076] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 600 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into particles of 40-60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0077] Example 31

[0078] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to the total metal loading of 1 wt% in the catalyst product). It was heated to about 600 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, and then taken out and reduced at 300 °C under 30 mL / min H2 for 0.5 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into particles of 40-60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out at 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0079] Example 32

[0080] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to the total metal loading of 1 wt% in the catalyst product). It was heated to about 600 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C, taken out, and reduced at 800 °C under 30 mL / min of H2 for 4 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into particles of 40-60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a gas stream of 30 ml / min with 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0081] Example 33 (comparative example)

[0082] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-Rutile was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, and then taken out and reduced at 600 °C under 30 mL / min H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0083] Example 34 (Comparative Example)

[0084] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1 with a total molar amount of 0.1 mmol. Then, the reducible oxide support SiO2 was added to the suspension (the mass of the support was calculated based on the total metal loading of 1 wt% in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen (-196 °C), taken out, and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES and was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / SiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0085] Example 35 (Comparative Example)

[0086] H2PtCl6 and Pd(NO3)2 were added to 100 mL of aqueous solution in a molar ratio of Pt:Pd = 1:1 with a total molar amount of 0.1 mmol. Then, the reducible oxide support SiO2 was added to the suspension (the mass of the support was calculated based on the total metal loading of 1 wt% in the catalyst product). The mixture was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen (-196 °C), taken out, and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPd was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES and was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPd / SiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (gcat · h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation, etc.

[0087] Example 36 (Comparative Example)

[0088] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution according to the molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1 with a total molar amount of 0.1 mmol. Then, the reducible oxide support TiO2 - Anatase was added to this suspension (the mass of the support was added according to the total metal loading of 1 wt% in the catalyst product). It was heated to about 100 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, taken out and reduced at 600 °C under 30 mL / min H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40 - 60 mesh particles, which were added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat · h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation, etc.

[0089] Example 37 (Comparative Example)

[0090] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2 - Anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 1000 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO - FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high - entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP - OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40 - 60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high - entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0091] Example 38 (Comparative Example)

[0092] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution at a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:10:1:1:1. Then, the reducible oxide support TiO2 - Anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen - 196 °C, taken out and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO - FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high - entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP - OES, which was consistent with the feeding loading. After the catalyst was synthesized, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40 - 60 mesh particles, which were added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high - entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0093] Example 39 (comparative example)

[0094] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol at a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2 - Anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched rapidly with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced at 900 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO - FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high - entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP - OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40 - 60 mesh particles, which were added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high - entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0095] Example 40 (comparative example)

[0096] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-Anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 200℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400°C. The reaction process is as follows: 100 mg of PtPdNiCoFe / TiO2 is mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0097] Example 41 (Comparative Example)

[0098] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1 with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-Anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 5h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400°C. The reaction process is as follows: 100 mg of PtPdNiCoFe / TiO2 is mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0099] Example 42 (Comparative Example)

[0100] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1 with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-Anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 0.1h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400°C. The reaction process is as follows: 100 mg of PtPdNiCoFe / TiO2 is mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400°C in a 30 ml / min gas flow of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The air velocity is 20000 ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0101] Example 43 (Comparative Example)

[0102] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2 - Anatase was added to the suspension (the mass of the support was added according to the total metal loading of 0.1 wt% in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen, -196 °C. After taking it out, it was reduced at 600 °C under 30 mL / min of H2 for 2 h. The total loading of PtPdNiCoFe was 0.1 wt%. The structure of the catalyst was characterized by CO - FTIR and TEM, and it was found that the alloy nanoparticles did not contain all metal components. The size of the high - entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP - OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 400 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into particles of 40 - 60 mesh, and then added to a fixed bed. Methane combustion reaction was carried out by heating to 400 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high - entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0103] Example 44 (comparative example)

[0104] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, Fe(NO3)3 were added to 100mL aqueous solution in a molar ratio of Pt:Pd:Ni:Co:Fe=1:1:1:1:1, with a total molar amount of 0.1mmol. Then, the reducible oxide carrier TiO2-anatase was added to the suspension (the mass of the added carrier was calculated based on the total metal element loading of 1wt% in the catalyst product), heated to about 400℃ for 10min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196℃, taken out and reduced at 600℃, 30mL / min H2 for 2h. The total loading of PtPdNiCoFe was 1wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high entropy alloy nanoparticles was between 2 and 10nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feed loading. After the catalyst is synthesized, it is used for methane combustion at 400oC. The reaction process is as follows: 100mg PtPdNiCoFe / TiO2 is mixed with 2g quartz sand and formed into 40-60 mesh particles, which are added to a fixed bed. The methane combustion reaction is heated to 400℃ in a 30ml / min air flow of 0.5vol% CH4, 10vol% O2, and 89.5vol% N2. The air velocity is 50000ml / (g cat h). The preparation method of the high entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0105] Example 45 (Comparative Example)

[0106] H2PtCl6, Pd(NO3)2, Ni(NO3)2, Co(NO3)2, and Fe(NO3)3 were added to 100 mL of aqueous solution in a total molar amount of 0.1 mmol with a molar ratio of Pt:Pd:Ni:Co:Fe = 1:1:1:1:1. Then, the reducible oxide support TiO2-anatase was added to the suspension (the mass of the support was added according to 1 wt% of the total metal loading in the catalyst product). It was heated to about 400 °C and maintained for 10 min, quenched with liquid nitrogen to the boiling point of liquid nitrogen -196 °C, and then taken out and reduced under H2 at 600 °C and 30 mL / min for 2 h. The total loading of PtPdNiCoFe was 1 wt%. The structure of the catalyst was characterized by CO-FTIR and TEM, and it was found that each metal was uniformly dispersed in the nanoparticles. The size of the high-entropy alloy nanoparticles was between 2 and 10 nm. The metal loading in the catalyst was characterized by ICP-OES, which was consistent with the feeding loading. After synthesizing the catalyst, it was used for methane combustion at 200 °C. The reaction process was as follows: 100 mg of PtPdNiCoFe / TiO2 was mixed with 2 g of quartz sand and formed into 40-60 mesh particles, which were then added to a fixed bed. Methane combustion reaction was carried out by heating to 200 °C in a 30 ml / min gas stream of 0.5 vol% CH4, 10 vol% O2, and 89.5 vol% N2. The space velocity was 20000 ml / (g cat ·h). The preparation method of this high-entropy alloy nanocatalyst has the characteristics of low required temperature and simple operation.

[0107] Table 1 Reaction evaluation results of methane combustion at 440 °C in Examples 1-26. The products were CO2 and H2O

[0108]

[0109]

[0110]

[0111] The results showed that:

[0112] Examples 1 to 3 in combination with Comparative Example 43 demonstrated that within the patented metal loading range (0.5 - 5 wt%), the catalyst had good performance in catalytic methane combustion. Examples 4 to 8 in combination with Comparative Example 38 demonstrated that within the patented metal molar ratio range (the molar ratio of any two of the metals was 0.5 - 2), the catalyst had good performance in catalytic methane combustion. Examples 9 to 16 in combination with Comparative Examples 33 - 34 demonstrated that within the patented reducible oxide support range (TiO2 - anatase, CeO2, ZrO2, In2O3, Fe2O3, Nb2O5, MoO3, SnO2, Ga2O3, PrO2), the catalyst had good performance in catalytic methane combustion. Examples 17 to 18 demonstrated that within the patented range of methane combustion inert gas types (N2, He, Ar), the catalyst had good performance in catalytic methane combustion. Examples 19 to 20 in combination with Comparative Example 44 demonstrated that within the patented methane space velocity range (5000 - 40000 ml / (g cat ·h)), the catalyst had good performance in catalytic methane combustion. Examples 21 to 23 demonstrated that within the patented CH4 / O2 ratio (1:20 - 1:5), the catalyst had good performance in catalytic methane combustion. Examples 24 to 25 in combination with Comparative Example 45 demonstrated that within the patented methane combustion reaction temperature range (300 - 800 °C), the catalyst had good performance in catalytic methane combustion. Examples 26 to 28 demonstrated that within the patented high - entropy alloy metal component range (Pt, Pd, Ni, Co, Fe, Zn, Zr, Cu, Ir, Au, Mn, Cr, V), the catalyst had good performance in catalytic methane combustion. Example 2 in combination with Comparative Example 35 showed that the high - entropy alloy had better catalytic activity for methane combustion compared to the bimetallic alloy. Examples 2, 29 to 30 in combination with Comparative Examples 36 - 37 demonstrated that within the patented high - entropy alloy calcination temperature range (300 - 600 °C), the catalyst had good performance in catalytic methane combustion. Examples 2, 31 to 32 in combination with Comparative Examples 39 - 40 demonstrated that within the patented high - entropy alloy reduction temperature range (300 - 800 °C), the catalyst had good performance in catalytic methane combustion. Examples 2, 31 to 32 in combination with Comparative Examples 41 - 42 demonstrated that within the patented high - entropy alloy reduction time range (0.5 - 4 h), the catalyst had good performance in catalytic methane combustion.

[0113] The high - entropy alloy catalyst demonstrated advantages such as high conversion rate, low ignition temperature, and long lifespan in methane combustion compared to single - metal catalysts or bimetallic alloy catalysts.

Claims

1. A method for synthesizing a high-entropy alloy catalyst, characterized by: The carrier is a reducible metal oxide, and the active phase is a high-entropy alloy; the active phase is supported on the carrier; The preparation process of the high-entropy alloy catalyst is as follows: impregnate the metal precursor on the surface of the reducible metal oxide, then heat the reducible metal oxide loaded with the metal precursor to 300-600 °C and maintain for 10-20 min, then directly immerse the heated high-temperature mixture into liquid nitrogen to cool to the liquid nitrogen temperature, take it out and naturally warm up to room temperature, and then reduce the mixture with hydrogen at 300-800 °C for 0.5-4 h to prepare the high-entropy alloy catalyst; The constituent metals of the high-entropy alloy active phase are any combination of four or more elements selected from Pt, Pd, Ni, Co, Fe, Zn, Zr, Cu, Ir, Au, Mn, Cr, V, which is the active phase of the high-entropy alloy catalyst; the proportion of the content of each metal in the high-entropy alloy active phase can be adjusted arbitrarily, and usually the molar ratio of any two metals in each metal is 0.5-2:0.5-2.

2. The method according to claim 1, characterized in that: The reducible metal oxide carrier can be one or more of TiO2-anatase, CeO2, ZrO2, In2O3, Fe2O3, Nb2O5, MoO3, SnO2, Ga2O3, PrO2.

3. The method according to claim 1, characterized in that: The total metal loading of the high-entropy alloy active phase in the catalyst is 0.5wt% - 5wt%.

4. The method according to claim 1, characterized in that: The proportion of the content of each metal in the high-entropy alloy active phase can be adjusted arbitrarily. Usually, the molar ratio of any two metals in each metal is 0.95-1.05:0.95-1.05, and the total metal loading of the high-entropy alloy active phase in the catalyst is 0.95-1.05wt%.

5. The method according to claim 1, characterized in that: The preparation process of the high-entropy alloy catalyst is as follows: impregnate the metal precursor on the surface of the reducible metal oxide, then heat the reducible metal oxide loaded with the metal precursor to 395-405 °C and maintain for 10-20 min, then directly immerse the heated high-temperature mixture into liquid nitrogen to cool to the liquid nitrogen temperature, take it out and naturally warm up to room temperature, and then reduce the mixture with hydrogen at 595-605 °C for 0.5-4 h to prepare the high-entropy alloy catalyst.

6. The method according to claim 1 or 5, characterized in that: The mixture is directly immersed in liquid nitrogen for cooling, and the cooled temperature is near the boiling point of liquid nitrogen, that is, -197~-196 °C.

7. A high-entropy alloy catalyst prepared by the method according to any one of claims 1-6.

8. The catalyst according to claim 7, characterized in that: The particle size of the high-entropy alloy of the active phase is 2-10 nm.

9. Application of the high-entropy alloy catalyst according to claim 7 or 8 in methane combustion.

10. The application according to claim 9, characterized in that: The inert atmosphere for methane combustion includes one or more of N2, Ar, He; The inert gas accounts for 50% - 90% of the total gas volume, and the rest is CH4 and O2; The methane space velocity on the catalyst is 5000 - 40000 ml / (g cat ·h), The molar ratio of CH4 to O2 is 1:20~1:5; The reaction temperature range is 300-800 °C.

11. According to the application described in claim 10, the characteristics are: The inert gas accounts for 50-55% of the total gas volume, and the rest is CH4 and O2; The methane space velocity on the catalyst is 15,000 - 25,000 ml / (g cat ·h); The molar ratio of CH4 to O2 is 1:15 to 1:20; The reaction temperature range is 400 to 600 °C.

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