An inverse catalyst rich in surface oxygen vacancy defects, a preparation method thereof, and an application thereof

Abstract

The present invention relates to the technical field of catalytic materials, and discloses an inverse catalyst rich in surface oxygen vacancy defects, a preparation method thereof and an application. The preparation method includes the steps of: ball-milling and mixing a copper precursor and a transition metal precursor, and obtaining the inverse catalyst through primary calcination and hydrogen reduction; the copper element in the copper precursor and the transition metal precursor accounts for more than 50 wt% of the total moles of metal elements. By simple ball-milling and calcination, an inverse copper-based catalyst with rich oxygen defects is prepared for the catalyst. The synthesis method has simple operation and mild conditions. Due to the efficient synergistic effect between the metal Cu and the support in the catalyst, when it catalyzes the reduction of carbon dioxide to methanol, both the selectivity and the activity show excellent levels.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic materials, and particularly to a reverse-phase catalyst rich in surface oxygen vacancy defects, a preparation method thereof, and an application thereof. Background Art

[0002] The advent of the industrial age has forced humanity to rely on fossil fuels as the main energy source in the past two hundred years, and the combustion of fossil energy has led to a large amount of emissions of greenhouse gases represented by carbon dioxide (CO2). The global warming caused by excessive CO2 emissions has led to frequent extreme weather, increasingly threatening the natural environment on which humanity depends for survival. Carbon reduction and emission reduction have become the common concern of the international community.

[0003] Methanol is an important basic organic chemical raw material and a bulk chemical product. It is the basic substance of C1 chemistry and also a new type of environmentally friendly, clean, and high-quality fuel with great development prospects. Using solar energy to photolyze water and the electric energy generated by other renewable energy sources to electrolyze water to produce hydrogen, and synthesizing methanol with CO2 as the carbon source is of great significance for constructing a C1 chemical system based on CO2, reducing the impact of CO2 on the environment, and developing a carbon cycle economy.

[0004] Inspired by the successful application of the Cu / ZnO / Al2O3 catalyst for synthesizing methanol by hydrogenation of CO in industry, in the past few decades, copper-based catalysts have been widely studied for hydrogenation of CO2. However, for a long time, there has been a controversy about whether the main active site is the Cu-Zn bimetallic alloy site or the Cu / ZnO interface site, which has hindered the design of advanced catalysts.

[0005] Recently, with the development of in-situ characterization techniques, researchers have observed the consumption of oxygen vacancies during the reaction process and gradually recognized their importance for catalytic performance (Nat. Catalysis, 2021, 4, 488 - 497). However, precisely synthesizing catalysts rich in oxygen vacancies is particularly challenging (Science, 2017, 355, 1296 - 1299). Summary of the Invention

[0006] Aiming at the problems of poor catalytic performance of the catalyst for synthesizing methanol by hydrogenation of CO2 and the complex and difficult preparation of catalysts rich in oxygen vacancies, the present invention provides a preparation method for a reverse-phase catalyst rich in oxygen vacancy defects, and prepares a reverse-phase copper-based catalyst with rich oxygen defects through simple ball milling and calcination. The synthesis method has the characteristics of simple operation and mild conditions.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A preparation method of an inverse catalyst rich in surface oxygen vacancy defects, comprising the steps of: ball-milling and mixing a copper precursor and a transition metal precursor, followed by a first calcination and hydrogen reduction to obtain the inverse catalyst, wherein the copper element in the copper precursor and the transition metal precursor accounts for more than 50 wt% of the total moles of metal elements.

[0009] Since oxygen vacancies mainly exist in transition metal oxides, we changed the catalyst structure from the traditional Cu / MO x to MO x / Cu (inverse structure), where MO x clusters are dispersed on the Cu substrate. By means of ball milling, oxygen vacancies are created at the two-phase interface, enhancing the dispersion between Cu and the support, strengthening the metal-support interaction, promoting the activation of hydrogen on the metal surface, and thus constructing abundant oxygen vacancy defects on the catalyst; due to the efficient synergistic effect between Cu and the support, the catalyst rich in vacancy defects enhances the activation of CO2 and hydrogen reactants, ultimately achieving an efficient CO2 hydrogenation to methanol reaction.

[0010] Compared with various possible methods for preparing oxygen vacancies, such as heat treatment, reduction reaction, element doping, high-energy bombardment, and liquid exfoliation, etc., the preparation method of the present invention has the advantages of being simple, green, and mild in conditions, and has significant advantages, such as energy conservation and no liquid or gas waste emissions. The product has excellent catalytic activity and effects. In addition, the process of synthesizing the catalyst by this method is relatively simple, the operation is convenient, and it does not require complex experimental equipment or conditions, and is suitable for large-scale production.

[0011] The copper precursor is metallic copper or an organic / inorganic salt of copper; such as copper salts like copper acetate, copper nitrate, copper oxalate, copper halide, or copper carbonate, or metallic copper powder purchased or self-made. The self-made metallic copper includes the steps of: fully mixing a copper salt and a dispersant in a solvent under constant temperature conditions, slowly adding a reducing agent and maintaining the constant temperature, and after the reaction is complete, washing and drying.

[0012] The transition metal precursor is an oxide, organic salt, or inorganic salt of a transition metal; the transition metal is titanium or zinc. Such as titanium dioxide, titanium acetate, titanium chloride, titanium sulfate, titanium nitrate, zinc oxide, zinc acetate, zinc nitrate, zinc carbonate, or zinc chloride, etc.

[0013] The particle size of the copper precursor or the transition metal precursor is nanoscale or micron-scale. A precursor with a smaller particle size is more conducive to the ball milling process, is conducive to changes in the surface lattice structure, and may cause the generation of oxygen vacancies or the formation of structural defects.

[0014] The ball-to-material ratio during ball milling is 0.1 - 100; the rotation speed of the ball milling operation is 100 - 1000 rpm / min; the time of the ball milling operation is 1 - 20 h. Ensure the high dispersion of the Cu-containing precursor and the support. If the time is too short, dispersion cannot be achieved, and if the time is too long, powder re-aggregation occurs, reducing the dispersion degree of the precursor and the support; Further, by estimating the mechanical energy under different conditions, the correlation between the oxygen vacancy content and the mechanical energy is revealed, providing guidance for the controllable synthesis of oxygen-rich defective MO x / Cu.

[0015] The temperature range of the first calcination: 100 - 400 °C, and the calcination time range: 1 - 20 h. Ensure the removal of organic and inorganic impurities and enable the interaction between Cu and the support. If the calcination temperature is too low, impurities cannot be fully removed, and if the temperature is too high, the material structure will be damaged;

[0016] The temperature range of hydrogen reduction: 100 - 400 °C, and the reduction time range: 1 - 20 h. Ensure sufficient reaction with hydrogen to generate vacancy defects on the catalyst surface. If the reduction temperature is too low, the support cannot be reduced, and if the reduction temperature is too high, the material structure will be damaged.

[0017] The present invention also provides a reverse-phase catalyst rich in oxygen vacancy defects prepared by the described preparation method. The oxygen defect content of the reverse-phase catalyst is more than 20%; among them, the particle size of copper particles is below 100 nm, and the particle size of transition metal oxide particles is below 50 nm; the molar ratio of copper element in metal elements is 60% - 90%.

[0018] Preferably, the oxygen defect content of the reverse-phase catalyst is 20 - 40%.

[0019] The present invention also provides the application of the reverse-phase catalyst rich in oxygen vacancy defects in the thermal catalytic reduction of carbon dioxide to methanol. Due to the efficient synergistic effect between the metal Cu and the support in the catalyst, when it catalyzes the reduction of carbon dioxide to methanol, both the selectivity and the activity show excellent levels.

[0020] During application, the catalytic reaction temperature is 150 - 350 °C; the ratio of carbon dioxide to hydrogen is 1:3 - 1:5; the reaction pressure range is: 1 - 5 MPa. Preferably, the reaction pressure range is: 2 - 4 MPa.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention combines the methods of mechanical ball milling and hydrogen reduction, enhances the dispersion of transition metal oxides on Cu, and constructs rich oxygen vacancy defects on the catalyst; due to the efficient synergistic effect between Cu and transition metal oxides, a catalyst with a high concentration of oxygen vacancy defects is obtained; this catalyst achieves excellent efficiency in the thermal catalytic reaction of CO2 hydrogenation to methanol.

[0023] (2) The instruments involved in the catalyst of the present invention are common, the material cost is low, the preparation process is simple, the operation is convenient, and it has the potential for industrial application. Description of the Drawings

[0024] Figure 1 X-ray diffraction pattern of the inverse oxygen-rich defective catalyst ZnO 1-x / Cu prepared in Example 1.

[0025] Figure 2 TEM image of the inverse oxygen-rich defective catalyst ZnO 1-x / Cu prepared in Example 1.

[0026] Figure 3 XPS spectrum of the inverse oxygen-rich defective catalyst ZnO 1-x / Cu prepared in Example 1.

[0027] Figure 4 X-ray diffraction pattern of the inverse oxygen-rich defective TiO 2-x / Cu catalyst prepared in Example 3.

[0028] Figure 5 TEM image of the inverse oxygen-rich defective TiO 2-x / Cu catalyst prepared in Example 3.

[0029] Figure 6 Activity test chart for thermocatalytic hydrogenation of CO2 in Application Example 1. Detailed Description of the Invention

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Those skilled in the art make modifications or equivalent replacements on the basis of understanding the technical solutions of the present invention, and without departing from the spirit and scope of the technical solutions of the present invention, they should all be covered within the protection scope of the present invention.

[0031] The raw materials used in the following specific embodiments are all purchased from the market.

[0032] Example 1 Inverse Oxygen-Rich Defective ZnO 1-x / Cu Catalyst

[0033] (1) 500 mg of anhydrous copper acetate and 2 g of PVP (polyvinylpyrrolidone) were stirred and dispersed in 50 mL of ethanol under the condition of a constant-temperature water bath at 60 °C. 1600 mg of ascorbic acid was made into an 80 mL solution and gradually added dropwise to the above solution, and stirring was continued in the constant-temperature water bath at 60 °C for 1 hour. The resulting orange-red solution was centrifuged and dried in an oven overnight. The obtained solid powder was denoted as Cu nanoparticles with a particle size of 50 nm;

[0034] (2) 476 mg of Zn(NO3)2·6H2O was ultrasonically dispersed in 20 mL of deionized water; 250 mg of 2,2'-bipyridine was ultrasonically dispersed in 10 mL of methanol; 101 mg of oxalic acid was ultrasonically dispersed in 10 mL of deionized water; then, the latter two solutions were added to the zinc nitrate solution under stirring conditions and stirring was continued at room temperature for 1 hour. The resulting white solution was centrifuged and dried in an oven overnight. The obtained solid powder was denoted as ZnBO with a particle size of 20 nm;

[0035] (3) The above solid powders were added to a ball milling jar according to a Cu:Zn molar ratio of 8:2, and a certain amount of ZrO2 grinding balls were added, with a ball-to-material ratio of 15:1. Using a planetary ball mill, it was milled at a speed of 870 rpm for 4 h. The obtained solid was taken out and calcined in a muffle furnace at 400 °C for 4 h and reduced in an H2 atmosphere at 300 °C for 1 h to obtain a reverse-phase oxygen-rich defect catalyst, denoted as ZnO 1-x / Cu.

[0036] Figure 1 is the X-ray diffraction pattern of the prepared reverse-phase oxygen-rich defect catalyst ZnO 1-x / Cu. It can be seen from Figure 1 that after the reverse-phase loading of ZnO 1-x onto Cu, the crystal structures of the two were not significantly changed.

[0037] Figure 2 is the TEM image of the prepared reverse-phase oxygen-rich defect catalyst ZnO 1-x / Cu. It can be seen from Figure 2 that the ZnO 1-x particles are evenly distributed on Cu, where the size of ZnO 1-x is 2 - 5 nm and the size of Cu is 10 - 20 nm.

[0038] Figure 3 is the XPS spectrum of the prepared reverse-phase oxygen-rich defect catalyst ZnO 1-x / Cu. It can be seen from Figure 3 that there are abundant oxygen defects in the prepared catalyst.

[0039] Example 2 Reverse-phase oxygen-rich defect ZnO 1-x / Cu catalyst

[0040] (1) 500 mg of anhydrous copper acetate and 2 g of PVP were stirred and dispersed in 50 mL of ethanol under a constant temperature water bath condition of 60 °C. 1600 mg of ascorbic acid was made into an 80 mL solution and gradually added dropwise to the above solution, and stirring was continued in the constant temperature water bath at 60 °C for 1 hour. The obtained orange-red solution was centrifuged and dried overnight in an oven, and the resulting solid powder was denoted as Cu NPs with a particle size of 50 nm;

[0041] (2) 476 mg of Zn(NO3)2·6H2O was ultrasonically dispersed in 20 mL of deionized water; 250 mg of 2,2'-bipyridine was ultrasonically dispersed in 10 mL of methanol; 101 mg of oxalic acid was ultrasonically dispersed in 10 mL of deionized water; then, the latter two solutions were added to the zinc nitrate solution under stirring conditions and stirring was continued at room temperature for 1 hour. The obtained white solution was centrifuged and dried overnight in an oven, and the resulting solid powder was denoted as ZnBO with a particle size of 20 nm;

[0042] (3) The above solid powders were added to a ball milling jar according to a Cu:Zn molar ratio of 8:2, and a certain amount of ZrO2 grinding balls were added therein with a ball-to-material ratio of 15:1. Using a planetary ball mill, it was milled at a speed of 870 rpm for 1 h. The obtained solid was taken out and calcined in a muffle furnace at 400 °C for 4 h and reduced in a H2 atmosphere at 300 °C for 1 h to obtain a reverse-phase oxygen-rich defect catalyst.

[0043] Example 3 Reverse-phase oxygen-rich defect TiO 2-x / Cu catalyst

[0044] (1) 10 mL of tetrabutyl titanate was dispersed in 20 mL of ethanol and then fully mixed with another solution composed of 250 mL of ethanol, 10 mL of deionized water and 5 mL of hydrofluoric acid. Subsequently, the obtained mixture was stirred for 30 minutes and then transferred to a polytetrafluoroethylene-lined autoclave. The autoclave was maintained at a temperature of 180 °C and reacted for 20 hours. The reacted solution was centrifuged and dried overnight in an oven to obtain TiO2 solid powder with a particle size of 20 nm.

[0045] (2) 80 mg of TiO2 solid powder and 800 mg of anhydrous copper acetate were added to a ball milling jar with a Cu:Ti molar ratio of 8:1, and a certain amount of ZrO2 grinding balls were added therein with a ball-to-material ratio of 15:1. Using a planetary ball mill, it was milled at a speed of 870 rpm for 2 h. The obtained solid was taken out and calcined in a muffle furnace at 400 °C for 4 h and reduced in a H2 atmosphere at 300 °C for 1 h to obtain a reverse-phase oxygen-rich defect catalyst, denoted as TiO 2-x / Cu.

[0046] Figure 4 For the prepared reverse-phase oxygen-rich defect TiO2-x X-ray diffraction pattern of the TiO₂ / Cu catalyst. It can be seen from Figure 4 that after loading TiO₂ on Cu, the crystal structures of both are not significantly changed. 2-x

[0047] Figure 5 TEM image of the prepared inverse oxygen-rich defective TiO₂ / Cu catalyst. It can be seen from 2-x that the TiO₂ particles prepared by this method are uniformly distributed on Cu. Figure 5 2-x

[0048] Comparative Example 1 Preparation of ZnO / Cu-SO catalyst by co-precipitation method

[0049] (1) Dissolve 93 mg of Cu(NO₃)₂·5H₂O and 300 mg of Zn(NO₃)₂·6H₂O in 100 mL of mixed aqueous solution, and prepare another 250 mL of 1 mol / L Na₂CO₃ solution;

[0050] (2) Under heating conditions, simultaneously add the above two solutions dropwise into a beaker containing 100 mL of deionized water and stir well. By controlling the dropwise addition of the Na₂CO₃ solution, keep the pH value of the precipitation solution at about 8.0. Then continue to stir for 4 h and stand for aging for 12 h. Finally, filter the obtained precipitate several times, dry it in an oven at 80 °C, and calcine it in a muffle furnace at 600 °C for 4 h, and grind it to obtain an oxide solid solution catalyst, denoted as ZnO / Cu-SO.

[0051] Comparative Example 2 Supported Cu / ZnO catalyst

[0052] (1) Disperse 500 mg of anhydrous copper acetate and 2 g of PVP in 50 mL of ethanol under a constant temperature water bath condition of 60 °C. Prepare 1600 mg of ascorbic acid into an 80 mL solution and gradually add it dropwise to the above solution, and continue to stir in a constant temperature water bath at 60 °C for 1 hour. Centrifuge the obtained orange-red solution and dry it in an oven overnight to obtain a solid powder denoted as Cu NPs with a particle size of 50 nm;

[0053] (2) Ultrasonically disperse 476 mg of Zn(NO₃)₂·6H₂O in 20 mL of deionized water; ultrasonically disperse 250 mg of 2,2'-bipyridine in 10 mL of methanol; then ultrasonically disperse 101 mg of oxalic acid in 10 mL of deionized water; then add the latter two solutions to the zinc nitrate solution under stirring conditions and continue to stir at room temperature for 1 hour. Centrifuge the obtained white solution and dry it in an oven overnight to obtain a solid powder denoted as ZnBO with a particle size of 20 nm;

[0054] ​​​(3) Add the above solid powder into a ball milling jar with a Cu:Zn molar ratio of 4:6, and add a certain amount of ZrO2 grinding balls into it, with a ball-to-material ratio of 15:1. Use a planetary ball mill to grind at a speed of 870 rpm for 4 h. After taking out the obtained solid, calcine it in a muffle furnace at 400 °C for 4 h, and reduce it in an H2 atmosphere at 300 °C for 1 h to obtain the supported Cu / ZnO catalyst.

[0055] Example 4

[0056] According to the process of Example 1, change the ball-to-material ratio and ball milling time, and test the oxygen defect content in the catalyst. The results are shown in Table 1. It can be seen that the concentration of oxygen vacancies in the obtained material can be effectively regulated by adjusting the ball milling parameters. This level of control enhances the versatility and tunability of the synthesis process, contributing to the precise realization of the desired material properties.

[0057] Table 1 Defect content of catalysts under different ball milling conditions with the same precursor as in Example 1

[0058] Rotational speed, rpm Ball milling time, h Ball-to-material ratio Oxygen vacancy content, % 870 1 15：1 28.1 870 2 15：1 31.8 870 4 15：1 36.3 870 4 30：1 26.8 870 8 15：1 22.8

[0059] Example 5 Inverse oxygen-rich defect ZnO 1-x / Cu catalyst

[0060] (1) Disperse 500 mg of anhydrous copper acetate and 2 g of PVP in 50 mL of ethanol under the condition of a constant-temperature water bath at 60 °C with stirring. Prepare 1600 mg of ascorbic acid into an 80 mL solution and gradually add it dropwise to the above solution, and continue to stir in a constant-temperature water bath at 60 °C for 1 hour. Centrifuge the obtained orange-red solution and dry it in an oven overnight. The obtained solid powder is denoted as Cu NPs with a particle size of 50 nm;

[0061] (2) Ultrasonically disperse 476 mg of Zn(NO3)2·6H2O in 20 mL of deionized water; ultrasonically disperse 250 mg of 2,2'-bipyridine in 10 mL of methanol; then ultrasonically disperse 101 mg of oxalic acid in 10 mL of deionized water; afterwards, add the latter two solutions to the zinc nitrate solution under stirring conditions and continue to stir at room temperature for 1 hour. Centrifuge the obtained white solution and dry it in an oven overnight. The obtained solid powder is denoted as ZnBO with a particle size of 20 nm;

[0062] (3) Add the above solid powder into a ball milling jar with a Cu:Zn molar ratio of 5:2, and add a certain amount of ZrO2 grinding balls into it, with a ball-to-material ratio of 15:1. Use a planetary ball mill to grind at a speed of 870 rpm for 1 h. After taking out the obtained solid, calcine it in a muffle furnace at 400 °C for 4 h, and reduce it in an H2 atmosphere at 300 °C for 1 h to obtain the inverse oxygen-rich defect catalyst.

[0063] Performance evaluation of the catalyst

[0064] The performance of the catalysts prepared in the examples and comparative examples for the hydrogenation of CO2 to methanol was tested and evaluated. The performance evaluation was carried out in a fixed-bed reactor. The catalytic reaction was carried out in a quartz reaction tube, and the temperature was controlled by a thermocouple to achieve the thermocatalytic reaction.

[0065] Application Example 1

[0066] 1. Weigh 50 mg of the catalysts of Examples 1-3 and Comparative Examples 1-2, crush them to 80-100 mesh, and mix them thoroughly with 100 mg of 100-mesh SiC powder, and then fill them in the middle of a fixed-bed quartz reactor with an inner diameter of 7 mm. The quartz tube is placed in a programmed tube furnace.

[0067] 2. The catalyst was pre-activated in a H2 atmosphere at 300 °C for 1 h, and then the tube furnace was cooled down for the activity test.

[0068] 3. The mixed reaction gas consists of CO2 and H2 (1:3) and a small amount of N2 as the balance gas. The catalytic reaction pressure for recording the activity is 4.0 mPa, and the temperature range is 180-300 °C. The concentrations of methanol and carbon monoxide in the outlet mixed gas are analyzed by Shimadzu chromatography, and a set of data is obtained every 30 °C.

[0069] The selectivity of methanol was calculated by the following formula:

[0070]

[0071] The activity test results of the thermocatalytic hydrogenation of CO2 are shown in Table 2 and Figure 6 As shown, under thermocatalytic conditions, compared with the Cu / ZnO catalysts prepared with shorter ball-milling time (Example 2), ordinary co-precipitation method (Comparative Example 1), without using the inverse phase strategy (Comparative Example 2), and the copper-based defect-rich catalysts prepared with other transition metal oxides (Example 3), the catalyst prepared in Example 1 has a higher oxygen defect content and can achieve higher methanol reaction yields and selectivities.

[0072] Among them, the catalysts prepared in Examples 1-3 all have a relatively high oxygen defect content. The methanol yield reaches 0.34 g / g cat / h at 240 °C, and the methanol selectivity exceeds 82%. However, the oxygen defect content of the co-precipitation method of Comparative Example 1 and the Cu / ZnO catalyst of Comparative Example 2 is lower than 20%, and the efficiency of synthesizing methanol is low.

[0073] Comparing Examples 1-3, Example 1 can achieve the efficient synthesis of methanol at a lower temperature and has better product selectivity compared with the case of shorter ball-milling time in Example 2 or using other transition metal oxide precursors in Example 3.

[0074] Table 2 Defect content and catalytic CO2 hydrogenation activity test results of Examples 1-3 and Comparative Examples 1-2

[0075]

[0076]

Claims

1. Application of an inverse catalyst rich in surface oxygen vacancy defects in thermocatalytic reduction of carbon dioxide to methanol, characterized in that, The catalytic reaction temperature is 150 - 350 °C; the ratio of carbon dioxide to hydrogen is 1:3 - 1:5; the reaction pressure range is: 1 - 5 MPa; The preparation method of the reverse-phase catalyst includes the steps of: ball-milling and mixing a copper precursor and a transition metal precursor, and obtaining the reverse-phase catalyst through primary calcination and hydrogen reduction; the copper element in the copper precursor and the transition metal precursor accounts for 60% - 90% of the total moles of metal elements; the oxygen vacancy content of the reverse-phase catalyst is 20 - 40%; wherein the particle size of copper particles is below 100 nm, and the particle size of transition metal oxide particles is below 50 nm; During the ball-milling, the ball-to-material ratio is 15 - 30; the rotation speed of the ball-milling operation is 870 - 1000 rpm / min; the ball-milling operation time is 1 - 8 h; The temperature range of the primary calcination is: 100 - 400 °C, and the calcination time range is: 1 - 20 h; The hydrogen reduction is carried out in a hydrogen atmosphere, the temperature range is: 100 - 400 °C, and the reduction time range is: 1 - 20 h.

2. Use of the inverse catalyst rich in surface oxygen vacancy defects according to claim 1 in the thermal catalytic reduction of carbon dioxide to methanol, characterized in that, The copper precursor is metallic copper or an organic / inorganic salt of copper.

3. Use of the inverse catalyst rich in surface oxygen vacancy defects according to claim 1 in the thermal catalytic reduction of carbon dioxide to methanol, characterized in that, The transition metal precursor is an oxide, organic salt or inorganic salt of a transition metal; the transition metal is titanium or zinc.

4. Use of the inverse catalyst rich in surface oxygen vacancy defects according to claim 1 in the thermal catalytic reduction of carbon dioxide to methanol, characterized in that, The particle size of the copper precursor or the transition metal precursor is nanoscale or micron-scale.

Images