A high-stability single-atom rhenium-based catalyst, a preparation method therefor, and applications thereof

Abstract

The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and application thereof, and belongs to the field of catalysis. The application discloses a monatomic rhenium-based catalyst, a preparation method and

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst preparation, in particular to a high-stability single-atom rhenium-based catalyst, a preparation method and application thereof. BACKGROUND

[0002] Global carbon dioxide (CO2) emissions increase year by year with the rapid development of industry and the large demand of human beings for energy. The concentration of CO2 in the atmosphere increases by more than 2 ppm per year, reaching 412 ppm in 2022. The increasingly severe climate problems caused thereby have attracted the attention of the world. Rhenium-based catalysts can convert CO2 into syngas or feedstock for Fischer-Tropsch synthesis by reverse water-gas shift (RWGS) (CO2+H2—CO+H2O) using renewable hydrogen, which is an important way for CO2 resource utilization. However, the structure of CO2 molecule is stable and the catalytic conversion path is complex, and the methanation competition reaction (CO2+4H2—CH4+2H2O) is prone to occur in the high-temperature activation process, resulting in poor CO selectivity. Research has found that metal single atoms are active sites for reverse water-gas shift, and single-atom catalysts have excellent CO selectivity. According to the characteristics of CO2 molecule and the requirements of reverse water-gas shift reaction, it is urgent to develop a preparation method of low-cost, high-stability and high-activity single-atom rhenium-based catalyst.

[0003] Monatomic catalysts are widely used in heterogeneous catalysis due to their high activity, maximum atom utilization and minimum catalyst usage. Patent No. 201811258105.1 uses carbon-nitrogen materials or carbon materials to realize the co-loading of active metal monatomic and nanoparticles by impregnation method, precipitation method, sol-gel method, etc. This catalyst can effectively avoid the production of carbon deposition in the catalytic reaction of low-carbon alkane dehydrogenation to produce low-carbon olefin. Patent No. 201610586356.7 discloses a preparation method of monatomic catalysts of metal rhodium, ruthenium, platinum and palladium. First, a supported catalyst is prepared by impregnation method, and then nanoparticles are removed by concentrated hydrochloric acid and hydrogen peroxide to realize monatomic loading. This monatomic catalyst has excellent low-temperature activity and stability for the catalytic decomposition of anhydrous hydrazine. Patent No. 201711112117.9 discloses a preparation method of monatomic rhodium-loaded molecular sieve catalyst. This method mainly uses the confinement effect of molecular sieve to confine monatomic rhodium in the molecular sieve channel, and realizes the monatomic dispersion of rhodium atoms inside the molecular sieve by high-temperature calcination. Patent No. 201610936896.3 discloses a preparation of monatomic catalyst with graphene as substrate. The target metal ions are adsorbed and dispersed on the surface of graphene oxide, and then the dispersed metal ions are removed to realize the monatomic distribution of target metal ions on the surface of graphene oxide. Patent No. 202010141510.6 discloses a preparation method of metal monatomic catalyst. In the inert gas protection condition at-40℃, polyacetylenic compounds and aprotic solvents are mixed, and then organic strong acid and metal salt precursor are added. After heating, stirring, centrifugation and drying, the monatomic catalyst is obtained.

[0004] From the above disclosed monatomic catalyst preparation technologies, it can be found that traditional monatomic catalysts generally use impregnation method, hydrothermal method and coprecipitation method, etc. Through atom confinement or post-processing removal, etc. Steps are taken to realize the monatomic dispersion of the loaded metal on the surface of the oxide carrier. However, these technologies have problems such as low loading capacity, poor thermal stability and complex preparation process. At the same time, the preparation method of high-stability monatomic rhenium-based catalyst is still missing. In the reaction process of reverse water gas shift, high reaction temperature and water generated by reaction can easily cause the sintering deactivation of monatomic catalysts prepared by traditional methods. The Ostwald ripening model indicates that the reason for the increase of catalyst particles is that smaller particles evolve into mobile gas phase oxides at high temperature, which deposit and increase on the surface of the carrier. Ostwald ripening and gas phase migration of oxides are the main reasons for the deactivation of monatomic catalysts. If a ideal carrier is used to capture such mobile gas phase oxides and adsorb and fix them at specific sites to prevent their continuous migration and growth, i.e. gas phase induced capture synthesis, it is expected to prepare stable monatomic rhenium-based catalysts. SUMMARY

[0005] To solve the above problems, the first object of the present application is to provide a high stability single-atom rhenium-based catalyst.

[0006] To achieve the above object, the present application provides a high stability single-atom rhenium-based catalyst

[0007] A high stability single-atom rhenium-based catalyst characterized in that an oxide is used as a carrier and metal rhenium is used as an active component, and the metal rhenium is dispersed on the oxide carrier in the form of a single atom.

[0008] In addition to the above technical solution, the present application can also use or combine the following technical solutions:

[0009] As a preferred technical solution of the present application, the molar loading of rhenium supported on the oxide carrier is 0.1% to 10%.

[0010] As a preferred technical solution of the present application, the molar ratio of the rhenium metal loading is 0.1% to 2%.

[0011] As a preferred technical solution of the present application, the oxide carrier is any one of zirconium oxide, cerium oxide, titanium oxide or zinc oxide.

[0012] The second object of the present application is to provide a preparation method of a high stability single-atom rhenium-based catalyst.

[0013] To achieve the above object, the present application provides a preparation method of a high stability single-atom rhenium-based catalyst, which comprises the following steps:

[0014] Step one, calcining the oxide carrier at 500°C under a hydrogen atmosphere for 4 hours;

[0015] Step two, dissolving the rhenium precursor into deionized water to form a clear and transparent solution A;

[0016] Step three, adding the oxide carrier prepared in step one into the solution A prepared in step two to form a suspension B, stirring, drying, and obtaining a solid powder loaded with rhenium species;

[0017] Step four, calcining the solid powder under a mixed gas of hydrogen and argon to obtain a single-atom rhenium-based catalyst. The heating rate is 1°C / min, the calcination temperature range is 500°C, the holding time is 5h, and the hydrogen proportion is 20%.

[0018] In addition to the above technical solution, the present application can also use or combine the following technical solutions:

[0019] As a preferred technical solution of the present application, the oxide carrier in step one is any one of zirconium oxide, cerium oxide, titanium oxide or zinc oxide.

[0020] As a preferred technical solution of the present invention: the rhenium precursor in step two is any one of ammonium perrhenate, potassium perrhenate, sodium perrhenate or tetrabutylammonium perrhenate.

[0021] As a preferred technical solution of the present invention: the ratio of rhenium to water in step two is (1-10) mmol / L Re: (100-500) mL H2O.

[0022] As a preferred technical solution of the present invention: the molar ratio of the metal oxide to the rhenium precursor in step three is 20:1 to 1000:1.

[0023] As a preferred technical solution of the present invention: the stirring temperature in step three is 60-100℃ and the stirring time is 12-24h.

[0024] The third objective of this invention is to provide an application of a highly stable single-atom rhenium-based catalyst in the catalytic hydrogenation reaction of carbon dioxide.

[0025] Application of a highly stable single-atom rhenium-based catalyst in the catalytic hydrogenation of carbon dioxide.

[0026] To achieve the above objectives, this invention discloses the application of a highly stable single-atom rhenium-based catalyst in the catalytic hydrogenation of carbon dioxide. The catalytic reaction is carried out in a pressurized fixed-bed continuous flow reactor under the following conditions: pressure 1.0–8.0 MPa, temperature 200–400 °C, and space velocity 6000–40000 h⁻¹. -1 The volume ratio of hydrogen to carbon dioxide is 3:1. This single-atom rhenium-based catalyst can achieve highly selective, highly active, and high-temperature stable catalysis of CO2 hydrogenation to CO.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention provides a method for preparing a highly stable single-atom rhenium-based catalyst, comprising: firstly, treating a metal oxide support with hydrogen at high temperature to obtain a metal oxide with oxygen vacancies. These oxygen vacancies are uniformly distributed on the surface of the oxide support and can be used to capture, disperse, and immobilize gaseous oxides; then, selectively adsorbing a rhenium-based precursor onto the support, with rhenium as ReO4. - The ReO4 molecules are adsorbed onto the support surface; finally, through high-temperature calcination with reducing gas, the support continues to maintain a high-energy surface and may even be reduced to generate more oxygen vacancies. - The rhenium is reduced to a migratable gaseous oxide, which is then captured by oxygen holes in the support and further reduced to a metal. Through the strong interaction between the oxygen holes in the support and rhenium, further migration and growth of rhenium are prevented, forming a highly stable single-atom rhenium-based catalyst.

[0029] The single-atom rhenium-based catalyst prepared in the application has the characteristics of high activity, high selectivity and high stability in the reverse water gas shift reaction. The single-atom rhenium-based catalyst provided in the application utilizes the excellent H2 cracking and CO2 activation capacity of rhenium metal to promote the dissociation of H2 and the activation of CO2, which is beneficial to the reverse water gas shift reaction, and the CO2 conversion rate is much higher than that of other single-atom catalysts; the single-atom rhenium-based catalyst has the characteristics of high atom utilization rate and high product selectivity due to the high dispersion characteristics, and the selectivity of product CO is 100% in the reverse water gas shift reaction; the single-atom rhenium-based catalyst provided in the application utilizes the strong interaction between the carrier oxygen hole and rhenium to prevent rhenium from continuing to migrate and grow, thereby having excellent high-temperature sintering resistance and thermal stability.

[0030] Compared with the prior art, the single-atom rhenium-based catalyst is obtained in one step by using a simple thermal reduction method, high-temperature heat treatment in a reducing atmosphere, migration of rhenium in the form of gaseous oxide on the surface of the carrier, and then capture by the metal oxide carrier with holes. The method can also realize large-scale preparation of the single-atom rhenium-based catalyst, and the preparation method is simple. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The CO2 catalytic hydrogenation to CO catalytic activity results of a single-atom rhenium-based catalyst obtained for Examples 1-6 of the application;

[0032] Figure 2 The transmission electron microscope image of the single-atom rhenium-based catalyst prepared for Example 1;

[0033] Figure 3 The extended X-ray absorption fine structure spectrum of the single-atom rhenium-based catalyst prepared for Example 1;

[0034] Figure 4 The transmission electron microscope image of the single-atom rhenium-based catalyst prepared for Example 2;

[0035] Figure 5 The transmission electron microscope image of the single-atom rhenium-based catalyst prepared for Example 4;

[0036] Figure 6 The CO characteristic adsorption infrared diffuse reflectance spectrum of the single-atom rhenium-based catalyst prepared for Examples 5 and 6;

[0037] Figure 7 The stability test of the catalyst prepared for Examples 1 and 5;

[0038] Figure 8 The flowchart of the preparation method of a high-stability single-atom rhenium-based catalyst of the application. DETAILED DESCRIPTION

[0039] The application will be described in further detail below with reference to the drawings and specific embodiments.

[0040] A preparation method of a rhenium-based monatomic catalyst, comprising: first, gradually reducing an oxide carrier to obtain a high-defect oxide; then adding the oxide carrier into a rhenium precursor aqueous solution, and selectively adsorbing rhenium species on the surface of the oxide carrier; and finally, high-temperature treatment under a reducing atmosphere, so that the loaded rhenium species migrates in the form of a gaseous oxide, and the oxide carrier captures the rhenium species by a gaseous phase-induced mode to realize monatomic dispersion of the rhenium species, thereby obtaining a high-stability monatomic rhenium-based catalyst.

[0041] Further, the preparation method comprises the following steps:

[0042] (1) reducing treatment of an oxide carrier such as zirconia, ceria, titania or zinc oxide under a hydrogen atmosphere;

[0043] (2) dissolving a certain amount of a rhenium precursor into deionized water to obtain a transparent and clear solution;

[0044] (3) then adding the oxide carrier, and stirring vigorously at 60-100 DEG C, and continuing to stir until evaporation to dryness, thereby obtaining a solid powder loaded with rhenium species;

[0045] (4) finally, calcining the solid powder under a mixed gas of hydrogen and argon to obtain a monatomic rhenium-based catalyst, wherein the heating rate is 1 DEG C / min, the calcination temperature ranges from 500 DEG C, the maintenance time is 5 h, and the proportion of hydrogen is 20%.

[0046] Further improvement of the application is that the rhenium precursor aqueous solution is prepared by dissolving any one of ammonium perrhenate, potassium perrhenate, sodium perrhenate or tetrabutylammonium perrhenate into deionized water, wherein the ratio of rhenium to water is (1-10) mmoL Re:(100-500) mL H2O.

[0047] The oxide carrier comprises zirconia, ceria, titania or zinc oxide.

[0048] The molar ratio of the amount of the oxide carrier to rhenium is 20:1-1000:1.

[0049] The calcination temperature is 400 DEG C-600 DEG C.

[0050] The application of the rhenium-based monatomic catalyst in a carbon dioxide catalytic hydrogenation reaction, wherein the monatomic rhenium-based catalyst is directly used for catalyzing the reaction to generate CO from CO2 hydrogenation, and the catalytic reaction conditions are as follows: pressure 0.1-8.0 MPa, temperature 200-400 DEG C, space velocity 6000-40000 h-1, and the like. -1, the volume ratio of hydrogen and carbon dioxide = 3:1.

[0051] The present application provides a rhenium-based monatomic catalyst for catalytic hydrogenation of CO2, which is prepared by capturing rhenium atoms in a gas phase to disperse rhenium monatomic form on an oxide carrier for catalytic hydrogenation of CO2. The active component of the rhenium-based catalyst is dispersed in the form of monatomic; the molar loading of rhenium is 0.1% to 5.0%, preferably 1.0%. The metal oxide carrier is mainly an oxide carrier such as zirconia, ceria, titania or zinc oxide. The prepared monatomic catalyst can be directly used for catalytic reaction.

[0052] The catalytic activity of the catalyst for catalytic hydrogenation of carbon dioxide to synthesize methanol is evaluated in a high-pressure high-temperature fixed-bed continuous flow reactor. The fixed-bed reactor is equipped with a three-stage high-temperature reaction furnace, a mass flow meter, a back pressure valve and a gas distribution system, etc. The tail gas after reaction enters a gas chromatograph detector for product analysis. The gas chromatograph detector is composed of a thermal conductivity detector and a hydrogen flame detector double-channel detector for online analysis. The prepared catalyst is first pressed into tablets, crushed, and sieved into 40-60 mesh, and loaded in the middle of the reactor, and the upper and lower ends of the catalyst bed are filled with 60-80 mesh quartz sand. The catalyst evaluation conditions are as follows: pressure 0.1-8.0 MPa, temperature 200-400℃, space velocity 6000-40000h -1 , volume ratio of hydrogen and carbon dioxide = 3:1. Preferably, the reaction pressure is 5 MPa, the temperature is 300℃, the volume ratio of H2 and CO2 is 3:1, and the space velocity is 24000h -1 .

[0053] The following detailed description of the embodiments of the present application. It should be emphasized that the following description is merely exemplary, but not intended to limit the scope of the present application and its applications.

[0054] Example 1: 0.5g of titania carrier is reduced under hydrogen atmosphere; 0.01g of ammonium perrhenate is dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier is added to form a suspension, which is stirred vigorously at 100℃ until it is evaporated to dryness to obtain a solid powder of rhenium species loaded on titania; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio 20 / 80) to obtain a monatomic catalyst, the heating rate is 1℃ / min, the calcination temperature range is 500℃, the holding time is 5h, and the hydrogen proportion is 20%. Figure 2 The transmission electron microscopy image of the prepared monatomic rhenium-based catalyst. Figure 3 The extended X-ray absorption fine structure spectrum of the prepared monatomic rhenium-based catalyst. In 5MPa, 300℃, H2 and CO2 volume ratio is 3:1, space velocity is 24000h -1The CO2 conversion of the catalyst is 8.8% and the CO selectivity is 100% under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1. Figure 7 The CO2 conversion is stable during the 40-hour catalytic reaction, indicating that the catalyst has excellent stability.

[0055] Example 2: 0.5 g of zirconium oxide carrier is reduced under a hydrogen atmosphere; 0.01 g of ammonium perrhenate is dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier is added to form a suspension, which is stirred vigorously at 100°C until it is evaporated to dryness, obtaining a solid powder of rhenium species loaded on titanium oxide; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a single-atom catalyst, with a heating rate of 1°C / min, a calcination temperature range of 500°C, a holding time of 5h, and a hydrogen proportion of 20%. Figure 4 The transmission electron microscopy image of the prepared single-atom rhenium-based catalyst is shown in Figure 2. Under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1, the CO2 conversion of the catalyst is 8.8% and the CO selectivity is 100%. -1 The CO2 conversion of the catalyst is 8.8% and the CO selectivity is 100% under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1.

[0056] Example 3: 0.5 g of zinc oxide carrier is reduced under a hydrogen atmosphere; 0.01 g of ammonium perrhenate is dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier is added to form a suspension, which is stirred vigorously at 100°C until it is evaporated to dryness, obtaining a solid powder of rhenium species loaded on titanium oxide; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a single-atom catalyst, with a heating rate of 1°C / min, a calcination temperature range of 500°C, a holding time of 5h, and a hydrogen proportion of 20%. Under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1, the CO2 conversion of the catalyst is 6.5% and the CO selectivity is 100%. -1 The CO2 conversion of the catalyst is 8.8% and the CO selectivity is 100% under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1.

[0057] Example 4: 0.5 g of cerium oxide carrier is reduced under a hydrogen atmosphere; 0.01 g of ammonium perrhenate is dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier is added to form a suspension, which is stirred vigorously at 100°C until it is evaporated to dryness, obtaining a solid powder of rhenium species loaded on titanium oxide; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a single-atom catalyst, with a heating rate of 1°C / min, a calcination temperature range of 500°C, a holding time of 5h, and a hydrogen proportion of 20%. Figure 5 The transmission electron microscopy image of the single-atom rhenium-based catalyst is shown in Figure 4; under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1, the CO2 conversion of the catalyst is 6.5% and the CO selectivity is 100%. -1The CO2 conversion of the catalyst is 8.2% and the selectivity of CO is 100% under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1.

[0058] Example 5: 0.5 g of titanium oxide carrier was reduced under hydrogen atmosphere; 0.02 g of potassium perrhenate was dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier was added to form a suspension, which was stirred vigorously at 100°C until it was evaporated to dryness to obtain a solid powder of rhenium species loaded titanium oxide; finally, the solid powder was calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a monatomic catalyst, the heating rate was 1°C / min, the calcination temperature range was 500°C, the holding time was 5h, and the proportion of hydrogen was 20%. Figure 6 The CO characteristic adsorption infrared diffuse reflectance spectrum of the monatomic rhenium-based catalyst is shown in Figure 6. Under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1, the CO2 conversion of the catalyst was 10.2% and the selectivity of CO was 100%. -1 The stability test showed that the CO2 conversion remained stable during the 40h catalytic reaction process, indicating that the catalyst had excellent stability. Figure 7 The stability test showed that the CO2 conversion remained stable during the 40h catalytic reaction process, indicating that the catalyst had excellent stability.

[0059] Example 6: 0.5 g of titanium oxide carrier was reduced under hydrogen atmosphere; 0.01 g of potassium perrhenate was dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier was added to form a suspension, which was stirred vigorously at 60°C until it was evaporated to dryness to obtain a solid powder of rhenium species loaded titanium oxide; finally, the solid powder was calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a monatomic catalyst, the heating rate was 1°C / min, the calcination temperature range was 500°C, the holding time was 5h, and the proportion of hydrogen was 20%. Figure 6 The CO characteristic adsorption infrared diffuse reflectance spectrum of the monatomic rhenium-based catalyst is shown in Figure 6. Under the reaction conditions of 5 MPa, 300°C, H2 and CO2 volume ratio of 3:1, and space velocity of 24000 h-1, the CO2 conversion of the catalyst was 10.2% and the selectivity of CO was 100%. -1 The stability test showed that the CO2 conversion remained stable during the 40h catalytic reaction process, indicating that the catalyst had excellent stability.

[0060] Comparative Example 1: Synthesis of 1% Ni / TiO2 catalyst. 0.5 g of titanium oxide carrier was reduced under hydrogen atmosphere; 0.01 g of nickel nitrate was dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier was added to form a suspension, which was stirred vigorously at 60°C until it was evaporated to dryness to obtain a solid powder of nickel species loaded titanium oxide; finally, the solid powder was calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a monatomic catalyst, the heating rate was 1°C / min, the calcination temperature range was 500°C, the holding time was 5h, and the proportion of hydrogen was 20%. ℃The solid powder of the rhenium species supported on the alumina is obtained by stirring vigorously until dryness; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a monatomic catalyst, the temperature rising rate is 1°C / min, the calcination temperature range is 500°C, the maintaining time is 5h, and the hydrogen ratio is 20%. Performance tests show that the CO2 conversion rate of the catalyst is only 0.5%, and the catalytic performance is far lower than that of the monatomic catalyst prepared by the present application.

[0061] The synthesis of a 1% Re / Al2O3 catalyst. 0.5g of an alumina carrier is reduced under a hydrogen atmosphere; 0.01g of potassium perrhenate is dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier is added to form a suspension, and the solid powder of the rhenium species supported on the alumina is obtained by stirring vigorously at 60°C until dryness; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a monatomic catalyst, the temperature rising rate is 1°C / min, the calcination temperature range is 500°C, the maintaining time is 5h, and the hydrogen ratio is 20%. Catalytic performance tests show that when the catalyst carrier is changed from a reduced carrier to an alumina or other non-reduced carrier, the CO2 conversion rate of the catalyst is only 2.3%, and the catalytic performance is far lower than that of the monatomic catalyst prepared by the present application.

[0062] The synthesis of a 10% Re / MgO catalyst. 0.5g of a magnesia carrier is reduced under a hydrogen atmosphere; 0.01g of potassium perrhenate is dissolved in deionized water to obtain a transparent and clear solution; then the reduced oxide carrier is added to form a suspension, and the solid powder of the rhenium species supported on the magnesia is obtained by stirring vigorously at 60°C until dryness; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a monatomic catalyst, the temperature rising rate is 1°C / min, the calcination temperature range is 500°C, the maintaining time is 5h, and the hydrogen ratio is 20%. ℃ The solid powder of the rhenium species supported on the magnesia is obtained by stirring vigorously until dryness; finally, the solid powder is calcined under a mixed gas of hydrogen and argon (volume ratio of 20 / 80) to obtain a monatomic catalyst, the temperature rising rate is 1°C / min, the calcination temperature range is 500°C, the maintaining time is 5h, and the hydrogen ratio is 20%. Catalytic performance tests show that when the catalyst carrier is changed from a reduced carrier to a magnesia or other non-reduced carrier, the CO2 conversion rate of the catalyst is only 4.5%, and the CO selectivity is reduced to 52%, and the catalytic performance is far lower than that of the monatomic catalyst prepared by the present application, indicating that the rhenium species is not completely in the form of monatomic distribution, but also exists in a certain large particle.

[0063] The above specific embodiments are used to explain and illustrate the present application, and are only preferred embodiments of the present application, rather than limiting the present application, and any modification, equivalent replacement, improvement, etc. made to the present application falls within the protection scope of the present application.

Claims

1. A method for preparing a highly stable rhenium-based catalyst for the catalytic hydrogenation of carbon dioxide, characterized by: The catalyst has an oxide carrier and a metal rhenium active component, and the metal rhenium is dispersed on the oxide carrier in a monatomic form; The preparation method of the catalyst comprises the following steps: Step one: calcining the oxide carrier under a hydrogen atmosphere at 500 DEG C for 4 hours to obtain a metal oxide with oxygen defects; Step two: dissolving a rhenium precursor into deionized water to form a clear and transparent solution A, wherein the ratio of rhenium to water is (1-10) mmol Re : (100-500) mL H2O; Step three: adding the metal oxide carrier with oxygen defects obtained in step one into the solution A obtained in step two to form a suspension B, stirring at 60-100 DEG C for 12-24 hours, drying to obtain a solid powder loaded with rhenium species; Step four: calcining the solid powder under a mixed gas of hydrogen and argon to obtain a monatomic rhenium-based catalyst, the temperature rising rate is 1 DEG C / min, the calcination temperature is 500 DEG C, the maintaining time is 5 hours, and the volume ratio of hydrogen is 20%, The oxide carrier is zirconium oxide, cerium oxide, titanium oxide or zinc oxide. The rhenium precursor in step two is ammonium perrhenate, potassium perrhenate, sodium perrhenate or tetrabutylammonium perrhenate.

2. The method for preparing a high-stability rhenium-based catalyst for a carbon dioxide catalytic hydrogenation reaction according to claim 1, characterized by: The molar loading of rhenium loaded on the oxide carrier is 0.1% to 10%.

3. The method for preparing a high-stability rhenium-based catalyst for a carbon dioxide catalytic hydrogenation reaction according to claim 1, characterized by: The molar ratio of the metal oxide carrier with oxygen defects to rhenium in step three is 20:1 to 1000:

1. The molar loading of rhenium loaded on the oxide carrier is 0.1% to 10%. The molar ratio of the metal oxide carrier with oxygen defects to rhenium in step three is 20:1 to 1000:

1.

4. The use of the high-stability monatomic rhenium-based catalyst prepared by the preparation method according to any one of claims 1-3 in the catalytic hydrogenation reaction of carbon dioxide, characterized in that: The catalytic reaction is carried out in a fixed bed continuous flow reactor, and the reaction conditions are as follows: pressure 0.1 ~ 8.0 MPa, temperature 200 ~ 400℃, space velocity 6000 ~ 40000 h -1 , and the volume ratio of hydrogen and carbon dioxide = 3:1.

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