Supported high-entropy catalysts, methods of making and using the same

Abstract

The application discloses a supported high-entropy catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The supported high-entropy catalyst comprises a high-entropy active component and a titanium dioxide carrier. The high-entropy active component contains any four of indium, cobalt, nickel, zinc, aluminum and ruthenium, and copper. The average particle size of the titanium dioxide carrier is 100nm-150nm. Therefore, the supported high-entropy catalyst has excellent catalytic performance and stability in CO2 hydrogenation and CO oxidation reaction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysts, and particularly relates to a supported high-entropy catalyst as well as a preparation method and application thereof. BACKGROUND

[0002] The current widely used CO2 catalytic conversion technology is to convert CO2 into high-value-added chemicals such as methane, methanol, ethylene, etc. through hydrogenation reaction. The CuO-ZnO-Al2O3 (CuZnAl) catalyst developed by the British Imperial Chemical Industries Company has excellent catalytic performance under the conditions of 220-240℃ and 5-10 MPa. Based on the excellent catalytic performance and low cost of the CuZnAl catalyst, the development and modification of the CO2 hydrogenation catalyst are still around the CuZnAl catalyst, especially by optimizing the Cu-based material properties to improve its low-temperature performance and stability. Although there are also reports on high-efficiency CO2 hydrogenation catalysts of noble metals, their high cost, complex preparation process and the nature of active sites being easy to sinter at high temperatures also limit their application in the industrial field. In addition, with the implementation of the "double carbon" goal, in addition to converting CO2 into high-value-added chemicals on the application side, optimizing the reaction conditions (such as low temperature and low pressure) on the use side to reduce energy consumption while ensuring catalytic efficiency is also an important development direction.

[0003] High-entropy materials (high-entropy oxides and high-entropy alloys) have rich active sites, stable crystal structures, unique geometric compatibility and electronic structures, etc., which can catalyze the CO2 hydrogenation reaction and also can catalyze the CO oxidation reaction. Therefore, it is urgent to develop a catalyst with high-entropy material as the matrix. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the related art. To this end, one object of the present application is to propose a supported high-entropy catalyst as well as a preparation method and application thereof, which can adjust the spatial position of the high-entropy active component and the titanium dioxide carrier to optimize the material properties of the high-entropy component, has excellent catalytic performance and stability in CO2 hydrogenation and CO oxidation reactions, and the preparation method is simple, does not require high-temperature calcination, has low energy consumption and high yield.

[0005] In a first aspect of the present application, a supported high-entropy catalyst is proposed, comprising a high-entropy active component and a titanium dioxide carrier; the high-entropy active component contains any four of indium, cobalt, nickel, zinc, aluminum, ruthenium and copper; and the average particle size of the titanium dioxide carrier is 100-150 nm. Thus, the supported high-entropy catalyst has excellent catalytic performance and stability in CO2 hydrogenation and CO oxidation reactions.

[0006] According to one embodiment of the present application, the proportion of copper is 17.2%-23.8% based on the total amount of the high-entropy active component; and / or, the proportion of indium is 19.1%-20.7%; and / or, the proportion of cobalt is 19.1%-20.7%; and / or, the proportion of nickel is 19.1%-20.7%; and / or, the proportion of zinc is 19.1%-20.7%; and / or, the proportion of ruthenium is 19.1%-20.7%. Thus, the supported high-entropy catalyst has excellent catalytic performance and stability in CO2 hydrogenation and CO oxidation reactions.

[0007] According to one embodiment of the present application, the high-entropy active component contains copper, cobalt, nickel, zinc and ruthenium. Thus, the catalyst can further adsorb and activate CO2, thereby facilitating CO2 hydrogenation catalytic reaction.

[0008] According to one embodiment of the present application, the molar ratio of copper, cobalt, nickel, zinc and ruthenium in the high-entropy active component is 1:(0.8-1.2):(0.8-1.2):(0.8-1.2):(0.8-1.2). Thus, the catalyst can further adsorb and activate CO2, thereby more facilitating CO2 hydrogenation catalytic reaction.

[0009] According to one embodiment of the present application, the crystal phase of the titanium dioxide carrier is anatase, and anatase titanium dioxide has a large surface area and a stable structure. Thus, the supported high-entropy catalyst can be uniformly dispersed on the surface of the carrier.

[0010] According to one embodiment of the present application, the mass fraction of the high-entropy active component in the titanium dioxide carrier is 10%-18% based on the mass of the titanium dioxide carrier. Thus, the supported high-entropy catalyst can be monolayer / feathery layer dispersed on the surface of the carrier.

[0011] In the second aspect of the present application, a method for preparing the supported high-entropy catalyst of the first aspect is provided, comprising:

[0012] (1) preparing an inorganic salt precursor of the high-entropy active component into a solution;

[0013] (2) impregnating the solution in the titanium dioxide carrier, and drying to obtain a supported high-entropy catalyst precursor;

[0014] (3) reducing the supported high-entropy catalyst precursor to obtain the supported high-entropy catalyst.

[0015] Thus, the method for preparing the supported high-entropy catalyst of the present application uses impregnation method and reduction treatment, which is simple, does not require high-temperature calcination, has low energy consumption and high yield.

[0016] According to one embodiment of the present application, in step (1), the inorganic salt precursor of the active component comprises at least one of nitrate, sulfate or chloride. Thereby, the rapid decomposition of anion species can be promoted in the subsequent reduction process, and the low-temperature generation of high-entropy components can be realized.

[0017] According to one embodiment of the present application, in step (2), the temperature of the drying treatment is 90-120°C. Thereby, the generation of high-entropy components at a lower temperature can be realized.

[0018] According to one embodiment of the present application, in step (2), the time of the drying treatment is 6-12h. Thereby, the generation of high-entropy components in a shorter time can be realized.

[0019] According to one embodiment of the present application, in step (3), the temperature of the reduction treatment is 200-500°C. Thereby, the reduction preparation of supported high-entropy catalysts at a lower temperature can be realized.

[0020] According to one embodiment of the present application, in step (3), the heating rate of the reduction treatment is 3-5°C / min. Thereby, the rapid thermal combination among different metals can be avoided, and the formation of high-entropy components can be realized.

[0021] According to one embodiment of the present application, in step (3), the time of the reduction treatment is 2-4h. Thereby, the formation of high-entropy components in a shorter time can be realized, and the sintering and agglomeration of high-entropy components can be avoided.

[0022] In the third aspect of the present application, a method for treating a mixed gas containing carbon monoxide and oxygen is provided, wherein the mixed gas containing carbon monoxide and oxygen is mixed with the catalyst of the first aspect or the catalyst prepared by the method of the second aspect. Thereby, the catalyst of the present application has excellent catalytic performance and stability in CO oxidation reaction.

[0023] In the fourth aspect of the present application, a method for treating a mixed gas containing carbon dioxide and hydrogen is provided, wherein the mixed gas containing carbon dioxide and hydrogen is mixed with the catalyst of the first aspect or the catalyst prepared by the method of the second aspect. Thereby, the catalyst of the present application has excellent catalytic performance and stability in CO2 hydrogenation reaction.

[0024] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which:

[0026] Figure 1 is a flow chart of a method for preparing a supported high-entropy catalyst according to an embodiment of the present application.

[0027] Figure 2 is a H2-TPR spectrum of a supported high-entropy catalyst according to Example 1 of the present application.

[0028] Figure 3 is a scanning electron microscope image of a supported high-entropy catalyst according to Example 1 of the present application, wherein the red circles mark the formed high-entropy active component.

[0029] Figure 4 is a CO2-TPD curve of a supported high-entropy catalyst according to Example 1 of the present application. DETAILED DESCRIPTION

[0030] Embodiments of the present application are described in detail below with the intention to be explanatory but not limiting of the present application.

[0031] In a first aspect, the present application provides a supported high-entropy catalyst, comprising a high-entropy active component and a titania support; the high-entropy active component contains any four of indium, cobalt, nickel, zinc, aluminum, ruthenium, and copper; the average particle size of the titania support is 100-150 nm.

[0032] The inventors have found that when the support particle size is small (<100 nm), the high-entropy component formed during reduction agglomerates among the pores of the support due to the small support surface, resulting in poor catalytic performance, while at a larger support particle size (100-150 nm), the formed high-entropy component is relatively uniformly dispersed on the surface of the support, and by adjusting the titania support particle size (100-150 nm), the optimization of the spatial configuration of the high-entropy component and the titania can be achieved, and at the same time, small-particle-size high-entropy components can be obtained, and the interaction between the high-entropy component and the titania support can be improved. When the support particle size is further increased (>150 nm), the high-entropy components formed on the surface of the support are far apart from each other, and the interaction between them is weak, and their catalytic performance will also decrease. In addition, the titania support can easily induce the occurrence of hydrogen overflow effect, and thus can promote the reduction of the high-entropy component and the activation of hydrogen components during CO2 hydrogenation. Thus, based on the improvement of the spatial configuration of the high-entropy component and the titania support, the optimization of the physicochemical properties of the high-entropy component can be achieved, and the supported high-entropy catalyst exhibits excellent catalytic performance and stability in CO2 hydrogenation and CO oxidation reactions.

[0033] According to one embodiment of the present application, the copper accounts for 17.2%-23.8% of the total amount of the high-entropy active component, for example, 17.2%, 18.7%, 19.5%, 20.2%, 21.7%, 22.5%, 23.8%, etc.; and / or, the indium accounts for 19.1%-20.7%, for example, 19.1%, 19.7%, 20.2%, 20.7%, etc.; and / or, the cobalt accounts for 19.1%-20.7%, for example, 19.1%, 19.7%, 20.2%, 20.7%, etc.; and / or, the nickel accounts for 19.1%-20.7%, for example, 19.1%, 19.7%, 20.2%, 20.7%, etc.; and / or, the zinc accounts for 19.1%-20.7%, for example, 19.1%, 19.7%, 20.2%, 20.7%, etc.; and / or, the ruthenium accounts for 19.1%-20.7%, for example, 19.1%, 19.7%, 20.2%, 20.7%, etc. Thus, the supported high-entropy catalyst has excellent catalytic performance and stability in CO2 hydrogenation and CO oxidation reactions.

[0034] According to one embodiment of the present application, the high-entropy active component contains copper, cobalt, nickel, zinc and ruthenium, wherein the copper and zinc components are conducive to the CO2 adsorption process, the cobalt and nickel components are conducive to the hydrogenation process, and the ruthenium component can increase the hydrogen overflow effect. Thus, the supported high-entropy catalyst contains copper, cobalt, nickel, zinc and ruthenium, which can further adsorb and activate CO2, thereby facilitating the CO2 hydrogenation catalytic reaction.

[0035] According to one embodiment of the present application, the molar ratio of copper, cobalt, nickel, zinc and ruthenium in the high-entropy active component is 1:(0.8-1.2):(0.8-1.2):(0.8-1.2):(0.8-1.2), for example, 1:0.9:0.9:0.9:0.9, 1:1:1:1:1, 1:1.1:1.1:1.1:1.1, etc. Thus, by controlling the molar ratio of copper, cobalt, nickel, zinc and ruthenium in the high-entropy active component within the above range, CO2 can be further adsorbed and activated, thereby further facilitating the CO2 hydrogenation catalytic reaction.

[0036] According to one embodiment of the present application, the titanium dioxide carrier crystal phase is anatase. Thus, the supported high-entropy catalyst can promote the dispersion of the high-entropy component and the catalytic stability.

[0037] According to one embodiment of the present application, the high-entropy active component accounts for 10-18% of the mass of the titanium dioxide carrier, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, etc. Thus, by adjusting the mass fraction of the high-entropy active component in the titanium dioxide carrier within the above range, the aggregation of the high-entropy component can be avoided, the high-entropy component can be ensured to have a higher catalytic site and a suitable spatial distance, which is conducive to the migration and conversion of active species, thereby improving the catalytic performance. Therefore, the mass fraction of the high-entropy active component in the titanium dioxide carrier is 10-18% in the present application, which can maximize the improvement of the catalytic performance.

[0038] In the second aspect of the present application, a method for preparing the supported high-entropy catalyst of the first aspect is provided, which refers to Figure 1 , comprising:

[0039] S100: preparing an inorganic salt precursor of the high-entropy active component into a solution

[0040] In this step, the inorganic salt precursor of the high-entropy active component is prepared into a solution.

[0041] According to one embodiment of the present application, in S100, the inorganic salt precursor of the active component includes at least one of nitrate, sulfate or chloride, for example, copper nitrate, cobalt chloride, nickel nitrate, zinc nitrate, indium nitrate, ruthenium trichloride, etc., so that the decomposition of anion species can be achieved during the reduction and heating process.

[0042] According to one embodiment of the present application, in S100, the inorganic salt precursor of the high-entropy active component is prepared into an aqueous solution.

[0043] According to one embodiment of the present application, in S100, the molar concentration of the inorganic salt precursor solution is 60-140 mmol / L, for example, 60 mmol / L, 70 mmol / L, 80 mmol / L, 90 mmol / L, 100 mmol / L, 110 mmol / L, 120 mmol / L, 130 mmol / L, 140 mmol / L, etc.

[0044] S200: impregnating the solution into a titanium dioxide carrier to obtain a supported high-entropy catalyst precursor after drying

[0045] In this step, the solution is impregnated into a titanium dioxide carrier to obtain a supported high-entropy catalyst precursor after drying. Thus, the method for preparing a supported high-entropy catalyst in the present application adopts an impregnation method, which is simple, does not require high-temperature calcination, has low energy consumption and high yield.

[0046] According to one embodiment of the present application, in S200, the drying treatment temperature is 90-120°C, for example, 90°C, 100°C, 110°C, 120°C, etc. Thus, high-entropy components can be generated at a lower temperature.

[0047] According to one embodiment of the present application, in S200, the drying treatment time is 6-12h, for example, 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc. Thus, the volatilization of moisture can be achieved in a shorter time.

[0048] According to one embodiment of the present application, in S200, the impregnation method can be a stepwise equal-volume impregnation method, specifically, after equal-volume impregnation of the high-entropy component solution in the titanium dioxide carrier is static dried, the equal-volume impregnation and drying are repeated until all the solution is impregnated, and the static treatment time is 60 minutes each time, and the infrared lamp heat treatment time is 30 minutes each time.

[0049] According to one embodiment of the present application, in S200, the drying can be vacuum drying, the vacuum drying treatment temperature is 90-120°C, and the vacuum drying treatment time is 6-12h.

[0050] S300: reducing the supported high-entropy catalyst precursor to obtain a supported high-entropy catalyst

[0051] In this step, the supported high-entropy catalyst precursor is reduced to obtain a supported high-entropy catalyst. Thus, the method for preparing a supported high-entropy catalyst of the present application uses an impregnation method and a reduction treatment, and the low-temperature formation of high-entropy components is achieved by means of hydrogen overflow effect in the reduction process, which is simple, does not require high-temperature calcination, has low energy consumption, and has high yield.

[0052] According to one embodiment of the present application, in S300, the reduction treatment temperature is 200-500°C, for example, 200°C, 300°C, 400°C, 500°C, etc. Thus, the reduction preparation of the supported high-entropy catalyst at a lower temperature is achieved by introducing noble metal components (any four of indium, cobalt, nickel, zinc, aluminum, ruthenium, and copper).

[0053] According to one embodiment of the present application, in S300, the heating rate of the reduction treatment is 3-5°C / min, for example, 3°C / min, 4°C / min, 5°C / min, etc. Thus, the rapid thermal bonding between different metals can be avoided, thereby achieving the formation of high-entropy components.

[0054] According to one embodiment of the present application, in S300, the time for the reduction treatment is 2h-4h, for example, 2h, 3h, 4h, etc. Thus, the formation of high-entropy component in a short time can be achieved, and sintering and agglomeration of the high-entropy component can be avoided.

[0055] According to one embodiment of the present application, in S300, the reduction method can be direct reduction by hydrogen to obtain a supported high-entropy catalyst, or the catalyst can be directly used for catalytic reaction after reduction treatment in an active device (for example, a fixed bed reactor, a tube furnace, etc.).

[0056] According to one specific embodiment of the present application, the method for preparing the supported high-entropy catalyst is as follows: equimolar inorganic salt precursor of high-entropy component is added into water to prepare a mixed metal solution, then the mixed metal solution is added into a titanium dioxide carrier by using a stepwise equal-volume impregnation method, combined with standing, infrared lamp irradiation and vacuum drying to obtain a catalyst precursor. Finally, the supported high-entropy catalyst is obtained by hydrogen reduction treatment.

[0057] Thus, the method for preparing the supported high-entropy catalyst of the present application uses impregnation method and reduction treatment, which is simple, does not need high-temperature calcination, has low energy consumption and high yield.

[0058] In the third aspect of the present application, a method for treating a mixed gas containing carbon monoxide and oxygen is provided, wherein the mixed gas containing carbon monoxide and oxygen is mixed with the catalyst of the first aspect or the catalyst prepared by the method of the second aspect. Thus, the catalyst of the present application has excellent catalytic performance and stability in CO oxidation reaction.

[0059] According to one embodiment of the present application, in the mixed gas of carbon monoxide and oxygen, the volume ratio of carbon monoxide to oxygen is 1:10; the flow rate of the mixed gas is 100mL / min-300mL / min; the mass of the catalyst is 0.1g-0.2g; and the temperature for the mixed gas of carbon monoxide and oxygen to react with the catalyst is 50℃-300℃.

[0060] In the fourth aspect of the present application, a method for treating a mixed gas containing carbon dioxide and hydrogen is provided, wherein the mixed gas containing carbon dioxide and hydrogen is mixed with the catalyst of the first aspect or the catalyst prepared by the method of the second aspect. Thus, the catalyst of the present application has excellent catalytic performance and stability in CO2 hydrogenation reaction.

[0061] According to one embodiment of the present application, the volume ratio of carbon dioxide to hydrogen in the mixed gas containing carbon dioxide and hydrogen is 4:1; the flow rate of the mixed gas is 50 mL / min-100 mL / min; the mass of the catalyst is 0.2-0.5 g; and the temperature of the mixed gas containing carbon dioxide and hydrogen mixed with the catalyst is 200-550°C.

[0062] The present application will be described below with reference to specific examples, which are illustrative only and not limiting in any way.

[0063] In the following examples, the reagents or instruments not specified by the manufacturer are all conventional products that can be purchased on the market.

[0064] Example 1

[0065] Six water copper nitrate 0.4832 g, six water cobalt chloride 0.4758 g, six water nickel nitrate 0.5816 g, six water zinc nitrate 0.5950 g and ruthenium trichloride 0.7254 g were weighed respectively, then transferred to 16.6 mL of deionized water to prepare a mixed solution of 120 mM, denoted as solution L3. 4 g of TiO2 (anatase type) carrier was weighed in a polytetrafluoroethylene beaker, the particle size of TiO2 was 100 nm, and the L3 solution (12.1 mL) was added to the TiO2 carrier by using a stepwise equal-volume impregnation method, and after each step of impregnation saturation, it was placed for 110 minutes, then dried with an infrared lamp for 50 minutes, and after the solution was used up, it was transferred to a vacuum drying oven and treated at 110°C for 10 hours to obtain a supported high-entropy catalyst precursor. Further reduction treatment with hydrogen at 200°C for 3 hours (heating rate 2°C / min) obtained a black product as a supported high-entropy catalyst, denoted as catalyst M1, and the mass fraction of high-entropy components in catalyst M1 was 12% of the carrier.

[0066] Reference Figure 2 , the H2-TPR spectrum of the supported high-entropy catalyst of Example 1 shows that the catalyst prepared in Example 1 has a sharp reduction peak at low temperature and a flat reduction peak at high temperature, indicating that the high-entropy catalyst on the surface of the carrier is formed by reduction.

[0067] Reference Figure 3 , Figure 2 is a scanning electron microscope image of the supported high-entropy catalyst of Example 1 of the present application, wherein the red circles mark the formed high-entropy active components, and from Figure 2 it can be seen that the high-entropy components formed in the catalyst prepared in Example 1 are relatively uniformly dispersed on the surface of the carrier.

[0068] Reference Figure 4The CO2-TPD curve of the supported high-entropy catalyst of Example 1 shows that the catalyst prepared in Example 1 has a distinct low-temperature CO2 desorption peak (115 °C) and a distinct high-temperature CO2 desorption peak (762 °C).

[0069] Example 2

[0070] Example 2 was prepared in the same manner as Example 1 except that the particle size of the TiO2 support was 120 nm. The resulting supported high-entropy catalyst is denoted as catalyst M3.

[0071] Example 3

[0072] Example 3 was prepared in the same manner as Example 1 except that the particle size of the TiO2 support was 120 nm. The resulting supported high-entropy catalyst is denoted as catalyst M3.

[0073] Comparative Example 1

[0074] Example 3 was prepared in the same manner as Example 1 except that the particle size of the TiO2 support was 120 nm. The resulting supported high-entropy catalyst is denoted as catalyst M3.

[0075] Comparative Example 2

[0076] Take 0.24 g of catalyst D1 and grind until no particles are felt, then add 100 mL of deionized water to prepare a solution. Then the prepared solution is stepwise impregnated on the surface of 2 g of TiO2 carrier with a particle size of 100 nm in equal volume, and then placed in an infrared lamp (50 minutes) and a vacuum drying oven (100°C, 10 h) for heat treatment. The obtained supported catalyst is recorded as catalyst D2, and the mass fraction of high-entropy components in catalyst D2 is 24%.

[0077] Comparative Example 3

[0078] Take 0.4832 g of copper nitrate hexahydrate, 0.4758 g of cobalt chloride hexahydrate, 0.5816 g of nickel nitrate hexahydrate, 0.5950 g of zinc nitrate hexahydrate, and 0.7464 g of aluminum nitrate nonahydrate, respectively, and then transfer them to 25 mL of deionized water to prepare a mixed solution of 80 mM, which is recorded as solution L1. Take 4 g of TiO2 (anatase crystal form) carrier with a particle size of 30 nm and place it in a polytetrafluoroethylene beaker. The L1 solution (11.12 mL) is added to the TiO2 carrier by stepwise equal-volume impregnation. After each step of impregnation, the solution is allowed to stand for 90 minutes, and then it is dried with an infrared lamp for 30 minutes. After the solution is used up, it is transferred to a vacuum drying oven for treatment at 90°C for 6 hours to obtain a supported high-entropy catalyst precursor. After further reduction treatment with hydrogen at 350°C for 2 hours (at a heating rate of 4°C / min), the black product obtained is a supported high-entropy catalyst, which is recorded as catalyst D3. The mass fraction of high-entropy components in catalyst D3 is 6% of the carrier.

[0079] Comparative Example 4

[0080] Take 0.4832 g of copper nitrate hexahydrate, 0.5820 g of cobalt nitrate hexahydrate, 0.6012 g of indium nitrate, 0.5391 g of zinc sulfate hexahydrate, and 0.7464 g of aluminum nitrate nonahydrate, respectively, and then transfer them to 33 mL of deionized water to prepare a mixed solution of 60 mM, which is recorded as solution L2. Take 4 g of TiO2 (anatase crystal form) carrier with a particle size of 60 nm and place it in a polytetrafluoroethylene beaker. The L2 solution (16.02 mL) is added to the TiO2 carrier by stepwise equal-volume impregnation. After each step of impregnation, the solution is allowed to stand for 60 minutes, and then it is dried with an infrared lamp for 40 minutes. After the solution is used up, it is transferred to a vacuum drying oven for treatment at 100°C for 8 hours to obtain a supported high-entropy catalyst precursor. After further reduction treatment with hydrogen at 500°C for 2 hours (at a heating rate of 5°C / min), the black product obtained is a supported high-entropy catalyst, which is recorded as catalyst D4. The mass fraction of high-entropy components in catalyst D4 is 8% of the carrier.

[0081] Comparative Example 5

[0082] Take 4 g of alumina carrier in a polytetrafluoroethylene beaker, the particle size of Al2O3 is 100 nm, and use stepwise equal-volume impregnation method to add L3 solution (12.1 mL) into the Al2O3 carrier. After each step of impregnation saturation, stand for 110 minutes, and then dry with infrared lamp for 50 minutes. After the solution is used up, transfer it to a vacuum drying oven and treat at 110°C for 10 hours to obtain a supported high-entropy catalyst precursor. Further reduction treatment with hydrogen at 200°C for 3 hours (heating rate is 2°C / min) obtains a black product which is a supported high-entropy catalyst, recorded as catalyst D5. The mass fraction of high-entropy components in catalyst D5 accounts for 12% of the carrier.

[0083] Comparative Example 6

[0084] Take 4 g of TiO2(anatase crystal form) carrier in a polytetrafluoroethylene beaker, the particle size of TiO2 is 100 nm, and use stepwise equal-volume impregnation method to add L5 solution (12.1 mL) into the TiO2 carrier. After each step of impregnation saturation, stand for 110 minutes, and then dry with infrared lamp for 50 minutes. After the solution is used up, transfer it to a vacuum drying oven and treat at 110°C for 10 hours to obtain a supported high-entropy catalyst precursor. Further reduction treatment with hydrogen at 200°C for 3 hours (heating rate is 2°C / min) obtains a black product which is a supported high-entropy catalyst, recorded as catalyst D6. The mass fraction of high-entropy components in catalyst D6 accounts for 14% of the carrier.

[0085] Comparative Example 7

[0086] Six water copper nitrate 0.4832 g, six water cobalt chloride 0.4758 g, six water nickel nitrate 0.5816 g, six water zinc nitrate 0.5950 g and ruthenium trichloride 0.7254 g were weighed respectively and then transferred into 16.6 mL deionized water to prepare a mixed solution of 120 mM, which was recorded as solution L3. 4 g of TiO2(anatase type) carrier was weighed in a Teflon beaker, the particle size of TiO2was 200 nm, and the L3 solution (12.1 mL) was added to the TiO2carrier by using a stepwise equal-volume impregnation method, and after each step of impregnation saturation, it was placed for 110 minutes, and then dried with an infrared lamp for 50 minutes, and after the solution was used up, it was transferred to a vacuum drying oven and treated at 110°C for 10 hours to obtain a supported high-entropy catalyst precursor. After further reduction treatment with hydrogen at 200°C for 3 hours (the heating rate was 2°C / min), the black product obtained was a supported high-entropy catalyst, which was recorded as catalyst D7, and the mass fraction of high-entropy components in catalyst D7 was 12% of the carrier.

[0087] Test Example

[0088] 1. CO2 hydrogenation activity test

[0089] The catalysts of the above examples and comparative examples were applied to the CO2 hydrogenation activity test, and the activity and stability results of the catalysts were expressed as CO2 conversion rate, CO2 conversion rate (%) = (CO2 inlet - CO2 outlet) / CO2 inlet x 100%, and the CO2 concentration was tested by using an online chromatograph, and the test results are shown in Table 1.

[0090] The conditions of the CO2 hydrogenation activity test were as follows: the catalyst loading was 0.2 g, the reaction temperature was 200°C-550°C, and the CO2 / H2 (v / v = 1:4) mixed gas flow rate was 100 mL / min, wherein the CO2 volume fraction was 4%.

[0091] The CO2 hydrogenation stability test was carried out on the same device, and the test conditions were as follows: the catalyst loading was 0.2 g, the reaction temperature was 400°C, the raw gas flow rate was 100 mL / min, and the long-term stability test time was 50 h.

[0092] Table 1 CO2 conversion rate of the supported high-entropy catalysts obtained from examples 1-3 and comparative examples 1-7

[0093]

[0094] 2. CO oxidation activity test

[0095] The catalysts obtained in the above examples and comparative examples were applied to CO oxidation activity test, and the activity results of the catalysts were expressed by CO conversion rate, CO conversion rate (%) = (CO inlet - CO outlet) / CO inlet x 100%, the CO concentration was tested by MKS, and the results were shown in Table 2.

[0096] The conditions of the CO oxidation activity test were as follows: the catalyst loading was 0.1 g, the reaction temperature was 50-300℃, the CO / O2 (v / v = 1:10), the CO concentration was 1%, and the mixed gas flow rate was 300 mL / min.

[0097] Table 2 CO conversion rates of the supported high-entropy catalysts obtained in examples 1-3 and comparative examples 1-7

[0098]

[0099] From Table 1, it can be seen that the supported high-entropy catalysts obtained in examples 1-3 have excellent catalytic performance and stability in the CO2 hydrogenation reaction compared with the catalysts obtained in comparative examples 1-7. From Table 2, it can be seen that the supported high-entropy catalysts obtained in examples 1-3 have excellent catalytic performance in the CO oxidation reaction compared with the catalysts obtained in comparative examples 1-7. From Table 1, it can be seen that the catalyst prepared in example 1 has a CO2 conversion rate of 37.58% at 400℃, and the CO2 conversion rate reaches 55.47% at 550℃ as the temperature further increases, and the CO2 conversion rate can still reach 36.95% after 50 h of stability test at 400℃. From Table 2, it can be seen that the catalyst prepared in example 1 has a CO conversion rate of 98.24% at 300℃, and has excellent CO oxidation performance. Therefore, the supported high-entropy catalysts have excellent redox catalytic performance and stability.

[0100] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0101] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that changes, modifications, substitutions and variations can be made by those skilled in the art without departing from the scope of the present application.

Claims

1. Use of a supported high-entropy catalyst, characterized in that, The catalyst is used for catalyzing CO2 hydrogenation reaction or CO oxidation reaction, The catalyst comprises a high-entropy active component and a titanium dioxide carrier; the high-entropy active component contains cobalt, nickel, zinc, ruthenium and copper; the molar ratio of copper, cobalt, nickel, zinc and ruthenium in the high-entropy active component is 1:(0.8-1.2):(0.8-1.2):(0.8-1.2):(0.8-1.2); the proportion of copper is 17.2%-23.8% based on the total amount of the high-entropy active component; and the average particle size of the titanium dioxide carrier is 100-150 nm; The method for preparing the catalyst comprises: (1) preparing a solution by using inorganic salt precursors of the high-entropy active component; (2) impregnating the solution in the titanium dioxide carrier to obtain a supported high-entropy catalyst precursor after drying; (3) obtaining the catalyst by reducing the supported high-entropy catalyst precursor; Wherein, the CO2 hydrogenation reaction includes mixing a mixed gas containing carbon dioxide and hydrogen with the catalyst; and the CO oxidation reaction includes mixing a mixed gas containing carbon monoxide and oxygen with the catalyst.

2. Use of a supported high-entropy catalyst according to claim 1, characterized in that, The mass fraction of the high-entropy active component in the titanium dioxide carrier is 10%-18% based on the mass of the titanium dioxide carrier.

3. Use of a supported high-entropy catalyst according to claim 2, characterized in that, The crystal phase of the titanium dioxide carrier is anatase.

4. Use of the supported high-entropy catalyst according to claim 1, characterized in that, In step (1), the inorganic salt precursors of the active component include at least one of nitrate, sulfate or chloride.

5. Use of the supported high-entropy catalyst according to claim 1, characterized in that, In step (2), the drying conditions include: temperature of 90-120℃; and / or, time of 6-12h.

6. Use of the supported high-entropy catalyst according to claim 1, characterized in that, In step (3), the reduction conditions include: temperature of 200-500℃; and / or, heating rate of 3-5℃ / min; and / or, time of 2-4h.

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