A Cu / In₂O₃ catalyst with high methanol selectivity, its preparation method and application

Abstract

The application discloses a Cu / In2O3 catalyst with high methanol selectivity and a preparation method and application thereof, and belongs to the technical field of catalytic materials. The application adopts a low-temperature co-precipitation method to prepare an indium oxide carrier, dissolves copper salt in deionized water to prepare an impregnation solution, and adopts an equal-volume impregnation method to load the impregnation solution on the indium oxide carrier. In the catalyst prepared by the application, copper nanoparticles are highly dispersed on the surface of the indium oxide, and the two form a strong-interaction interface. The catalyst is used for a carbon dioxide hydrogenation methanol reaction, significantly improves the methanol selectivity of a non-noble metal catalyst, and has a good industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials technology, specifically relating to a Cu / In2O3 catalyst with high methanol selectivity, its preparation method, and its application. Background Technology

[0002] The hydrogenation of carbon dioxide to methanol is an important pathway for the resource utilization of carbon dioxide. The resulting methanol can be used as a basic chemical feedstock, as well as a liquid fuel and a hydrogen storage and transportation carrier. In this reaction, the methanol formation is thermodynamically limited. Low temperatures are beneficial for improving methanol selectivity, but carbon dioxide molecules are stable and difficult to activate. While increasing the temperature can improve the carbon dioxide conversion rate, it easily promotes the reverse water-gas shift reaction, leading to an increase in carbon monoxide byproducts. Therefore, developing catalysts that can simultaneously promote carbon dioxide and hydrogen activation while suppressing the reverse water-gas shift reaction is a key issue in this field.

[0003] In the prior art, copper-based catalysts are commonly used in the hydrogenation of carbon dioxide to methanol. Patent CN103272607A discloses a copper-based catalyst for the hydrogenation of carbon dioxide to methanol, which improves catalytic performance by improving the dispersion of the Cu / Zn / Al / Zr components through stabilizers and co-precipitation methods. Patent CN106390978B discloses a high-temperature resistant catalyst for the hydrogenation of carbon dioxide to methanol, which forms a composite metal oxide with Zn, Cd, or In and Zr or Cr, and can improve methanol selectivity under certain conditions. However, traditional copper-based catalysts tend to promote the reverse water-gas shift reaction, and oxide catalysts generally suffer from insufficient hydrogen activation capacity, making it difficult to simultaneously achieve high carbon dioxide conversion and high methanol selectivity.

[0004] Indium oxide-based catalysts have attracted attention in the hydrogenation of carbon dioxide to methanol due to the favorable effects of surface oxygen vacancies on carbon dioxide adsorption and conversion of oxygen-containing intermediates. Patent CN110479235B discloses a hexagonal indium oxide catalyst with a nano-hierarchical structure, which achieves high methanol selectivity in the hydrogenation of carbon dioxide to methanol. However, its preparation relies on hydrothermal aging and specific morphology control, and the synergistic effect between hydrogen activation and the metal-indium oxide interface is not further addressed. Patent CN114405505A discloses a platinum-modified indium oxide catalyst, which improves carbon dioxide hydrogenation activity and methanol selectivity by modifying In₂O₃ with Pt. However, this method uses the precious metal platinum, resulting in high costs and hindering low-cost large-scale applications.

[0005] Copper, as a non-precious metal additive, has good hydrogen dissociation ability and cost advantage, making it suitable for improving the hydrogen activation ability of indium oxide catalysts. A literature review (Journal of China University of Petroleum, 2023, 47(2): 166-172) reported a Cu-h-In2O3 catalyst, suggesting that the interface interaction between Cu and In2O3 can promote oxygen vacancy formation and hydrogen overflow; among which, 1% Cu-h-In2O3 achieved a carbon dioxide conversion rate of 4% and a methanol selectivity of 71% at 280℃ and 3 MPa. A literature review (Chinese Journal of Chemical Industry and Engineering, 2023, 74(8): 3366-3374) reported a Sn-doped In2O3 catalyst, where 0.5% Sn-In2O3 achieved a hydrogen activation rate of 4% at 300℃, 3 MPa, and a space velocity of 15000 mL·g. -1 ·h -1 Under the given conditions, the carbon dioxide conversion rate was 6.2% and the methanol selectivity was 70.4%. Increasing the Sn content could further improve the methanol selectivity, but it would decrease the carbon dioxide conversion rate.

[0006] Therefore, existing catalysts for the hydrogenation of carbon dioxide to methanol still have the following shortcomings: the methanol selectivity of copper-based catalysts is limited by the counter-current water gas side reaction; pure indium oxide catalysts have insufficient hydrogen activation capacity; noble metal-modified indium oxide catalysts are costly; and the methanol selectivity of existing non-noble metal-modified indium oxide systems still has room for improvement. Therefore, it is necessary to develop a catalyst preparation method that does not require noble metals, is simple to prepare, and can effectively control the surface structure of the indium oxide support, the dispersion state of copper species, and the Cu / In₂O₃ interfacial interaction, in order to improve the methanol selectivity in the carbon dioxide hydrogenation to methanol reaction. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] In view of the technical problems existing in the above and / or prior art, such as insufficient hydrogen activation capacity of non-precious metal indium oxide-based catalysts, difficulty in effectively controlling the dispersion state of copper species and the Cu / In2O3 interface interaction, and room for improvement in methanol selectivity, this invention is proposed.

[0009] One objective of this invention is to provide a method for preparing a Cu / In2O3 catalyst with high methanol selectivity. By systematically controlling the preparation conditions of the indium oxide support and the copper loading process, the interaction between the copper and indium oxide interfaces is optimized, significantly improving the methanol selectivity of the catalyst.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a Cu / In2O3 catalyst with high methanol selectivity, comprising, Indium salt solution and precipitant solution were added dropwise to deionized water at 0-10℃, while the temperature of the reaction system was kept constant during the addition. After the addition was completed, an aging treatment was performed. The resulting precipitate was filtered, washed, dried, and then calcined in air to obtain indium oxide support. A copper salt was dissolved in deionized water to prepare an impregnation solution. The impregnation solution was loaded onto the indium oxide support using an equal-volume impregnation method. After standing and aging and drying, the solution was calcined under an inert or reducing atmosphere to obtain a Cu / In2O3 catalyst.

[0011] In a preferred embodiment of the preparation method of the high methanol selectivity Cu / In2O3 catalyst of the present invention, the indium salt is one or more of indium nitrate, indium chloride, or indium sulfate. The precipitant is one or more of ammonium carbonate, sodium carbonate, sodium hydroxide, urea, or ammonia water; the amount of precipitant used is an excess amount to completely precipitate indium ions. Preferably, the molar ratio of precipitant to indium salt is 2~5:1, more preferably 3:1.

[0012] In a preferred embodiment of the preparation method of the high methanol selectivity Cu / In₂O₃ catalyst of the present invention, an aging treatment is performed, wherein the aging is carried out by standing at the reaction system temperature for no more than 24 hours. The entire aging process does not require stirring, which is beneficial for the crystal growth and particle size uniformity of the precipitate particles, while avoiding excessive stirring that could damage the precipitate structure.

[0013] As a preferred embodiment of the preparation method of the high methanol selectivity Cu / In2O3 catalyst of the present invention, the calcination is carried out in an air atmosphere at a temperature of 300~650℃ for 2~6 hours.

[0014] In a preferred embodiment of the preparation method of the high methanol selectivity Cu / In2O3 catalyst of the present invention, the copper salt is one or more of copper nitrate, copper chloride, copper acetate or copper sulfate. The amount of copper salt added is configured such that the copper loading in the Cu / In2O3 catalyst is 1~20 wt%.

[0015] In a preferred embodiment of the preparation method of the high methanol selectivity Cu / In2O3 catalyst of the present invention, the standing aging time does not exceed 4 hours.

[0016] As a preferred embodiment of the preparation method of the high methanol selectivity Cu / In2O3 catalyst of the present invention, the calcination is carried out under an inert atmosphere or a reducing atmosphere, the calcination temperature is 250~450℃, and the calcination time is 2~6 hours.

[0017] Another object of the present invention is to provide a highly methanol-selective Cu / In2O3 catalyst, prepared by the preparation method described in any of the preceding claims; The catalyst comprises an indium oxide support and copper nanoparticles loaded on its surface. The copper nanoparticles are highly dispersed on the surface of the indium oxide and form a strongly interacting interface structure with the indium oxide.

[0018] As a preferred embodiment of the high methanol selectivity Cu / In2O3 catalyst of the present invention, the copper loading is 1~20 wt%.

[0019] As a preferred embodiment of the high methanol selectivity Cu / In₂O₃ catalyst of the present invention, the catalyst has a specific surface area of ​​70~100 m². 2 / g.

[0020] Another object of the present invention is to provide the application of the highly methanol-selective Cu / In2O3 catalyst as described above in the reaction of carbon dioxide hydrogenation to methanol.

[0021] As a preferred embodiment of the application of the high methanol selectivity Cu / In₂O₃ catalyst of the present invention in the reaction of carbon dioxide hydrogenation to methanol, wherein: a mixture of hydrogen and carbon dioxide is introduced into the high methanol selectivity Cu / In₂O₃ catalyst, and the reaction is carried out at a reaction temperature of 200~300℃, a reaction pressure of 1~5 MPa, and a gas space velocity of 3000~20000 mL·g. -1 ·h -1 Under the given reaction conditions, hydrogenation is carried out to obtain methanol.

[0022] Compared with the prior art, the present invention has the following beneficial effects: This invention optimizes the interfacial structure between copper and indium oxide by modifying the preparation method of copper-supported indium oxide and controlling key parameters such as co-precipitation temperature, indium oxide calcination temperature, copper loading, and copper calcination temperature. In the resulting catalyst, copper nanoparticles are highly dispersed on the indium oxide surface, forming a strongly interacting interface. This catalyst, used in the hydrogenation of carbon dioxide to methanol, significantly improves the methanol selectivity of non-precious metal catalysts and shows promising prospects for industrial application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 The images are transmission electron microscope (TEM) images of the Cu / In2O3 catalysts prepared in Examples 1 to 10 of this invention.

[0024] Figure 2 This is a diagram showing the long-term catalytic performance of the Cu / In2O3 catalyst prepared in Example 1 of this invention in the reaction of carbon dioxide hydrogenation to methanol. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0028] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0029] Example 1

[0030] (1) Preparation of indium oxide support. Indium oxide support was prepared by coprecipitation. 10 mmol of indium nitrate was dissolved in 100 mL of deionized water and stirred until completely dissolved to obtain an indium nitrate solution. 30 mmol of ammonium carbonate was dissolved in 100 mL of deionized water to obtain an ammonium carbonate solution. Under ice-water bath conditions at 4℃, the indium nitrate solution and ammonium carbonate solution were added dropwise to 100 mL of deionized water in a parallel stream. During the addition, the temperature of the reaction system was kept constant at 4℃ while stirring vigorously. After the addition was completed, the mixture was allowed to stand at 4℃ for 3 hours. The resulting precipitate was washed 3 times with deionized water and 2 times with anhydrous ethanol, and dried at 80℃ for 12 hours. The dried precursor was placed in a muffle furnace and calcined at a heating rate of 5℃ per minute to 450℃ for 4 hours. After natural cooling, the indium oxide support was obtained.

[0031] (2) Copper loading. 0.38 g of copper nitrate trihydrate was dissolved in 1.5 mL of deionized water to prepare an impregnation solution. 2.0 g of the above indium oxide support was added dropwise to the support using an equal-volume impregnation method, with stirring during the addition. After impregnation, the mixture was allowed to stand at room temperature for 4 hours, and then dried at 80°C for 8 hours. The dried powder was placed in a tube furnace and calcined at 350°C for 4 hours under a nitrogen atmosphere at a heating rate of 5°C per minute. The copper loading of the resulting catalyst was 10 wt%. The resulting catalyst was designated Cu / In₂O₃-4-450-10-350.

[0032] Example 2

[0033] The preparation method is basically the same as in Example 1, except that the coprecipitation temperature is adjusted to 30°C in the first step, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In₂O₃-30-450-10-350.

[0034] Example 3

[0035] The preparation method is basically the same as in Example 1, except that the coprecipitation temperature is adjusted to 80℃ in the first step, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In2O3-80-450-10-350.

[0036] Example 4

[0037] The preparation method is basically the same as in Example 1, except that the calcination temperature of the indium oxide precursor is adjusted to 350°C in the first step, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In₂O₃-4-350-10-350.

[0038] Example 5

[0039] The preparation method is basically the same as in Example 1, except that the calcination temperature of the indium oxide precursor is adjusted to 550℃ in the first step, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In2O3-4-550-10-350.

[0040] Example 6

[0041] The preparation method is basically the same as in Example 1, except that the calcination temperature of the indium oxide precursor is adjusted to 650℃ in the first step, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In2O3-4-650-10-350.

[0042] Example 7

[0043] The preparation method is basically the same as in Example 1, except that in the second step, the amount of copper nitrate trihydrate is adjusted to 0.076 g, i.e., the copper loading is 2 wt%, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In2O3-4-450-2-350.

[0044] Example 8

[0045] The preparation method is basically the same as in Example 1, except that in the second step, the amount of copper nitrate trihydrate is adjusted to 0.76 g, i.e., the copper loading is 20 wt%, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In2O3-4-450-20-350.

[0046] Example 9

[0047] The preparation method is basically the same as in Example 1, except that the calcination temperature after copper loading is adjusted to 250℃ in the second step, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In2O3-4-450-10-250.

[0048] Example 10

[0049] The preparation method is basically the same as in Example 1, except that the calcination temperature after copper loading is adjusted to 450℃ in the second step, while the other conditions remain unchanged. The resulting catalyst is denoted as Cu / In2O3-4-450-10-450.

[0050] Product characteristics: The catalyst prepared in Example 1 was analyzed by high-resolution transmission electron microscopy, and the results are as follows: Figure 1 As shown. By Figure 1As can be seen, the indium oxide support exhibits a nanoparticle morphology, with copper nanoparticles dispersed on the indium oxide surface, and the particle size ranging from 2 to 8 nm. Further, lattice diffraction and lattice fringe spacing were measured in three different regions of the transmission electron microscopy (TEM) image of the catalyst from Example 1. The results show that the lattice fringes with a spacing of 0.25 nm correspond to the (11-1) crystal plane of copper oxide, and the lattice fringes with a spacing of 0.29 nm correspond to the (222) crystal plane of indium oxide. Both types of lattice fringes are clearly visible and interlaced at the interface.

[0051] The catalysts prepared in Examples 1 to 10 were subjected to nitrogen physical adsorption tests, and the specific surface area results are shown in Table 1. As can be seen from Table 1, the catalyst prepared in Example 1, using co-precipitation at 4℃ and calcination at 450℃, achieved the highest specific surface area of ​​97.8 m². 2 / g. In Examples 2 and 3, the specific surface area decreased to 73.5 m² as the coprecipitation temperature increased. 2 / g and 59.2 m 2 / g. In the comparison of indium oxide calcination temperatures, Example 4 showed a specific surface area of ​​89.3 m² when calcined at 350°C. 2 / g, Example 5 yielded 83.6m upon calcination at 550°C. 2 / g, in Example 6, the concentration decreased to 66.1 m upon calcination at 650°C. 2 / g. Regarding copper loading, the specific surface area in Example 7 was 94.2 m² when the loading was 2%. 2 / g, In Example 8, the specific surface area decreased to 75.5 m² at a 20% load. 2 / g. In the comparison of copper roasting temperatures, Example 9 had a specific surface area of ​​89.3 m² when roasted at 250°C. 2 / g, Example 10, calcined at 450°C, yielded 81.4 m. 2 / g. The above results indicate that low-temperature co-precipitation, suitable indium oxide calcination temperature, and copper calcination temperature are beneficial for obtaining catalysts with high specific surface area.

[0052] Performance testing: The hydrogenation of carbon dioxide to methanol was carried out in a fixed-bed reactor. 0.5 g of catalyst (40-60 mesh) was loaded into the reaction tube and pretreated at 300°C for 2 hours under a reaction atmosphere (5% H₂ / N₂). The reaction conditions were: reaction temperature 280°C, reaction pressure 3.0 MPa, feed gas composition H₂:CO₂:N₂ = 72:24:4 (volume ratio), and gas hourly space velocity (GHSV) 3000 mL·g⁻¹. -1 ·h -1 After gas-liquid separation, the reaction products are analyzed online by gas chromatography, and the liquid products are analyzed offline. CO2 conversion and methanol selectivity are calculated using the following formulas.

[0053] CO2 conversion rate = (CO2 feed rate - CO2 discharge rate) / CO2 feed rate × 100%

[0054] Methanol selectivity = Methanol production / (Total CO2 converted - CO production) × 100%

[0055] The performance of the catalysts for CO2 hydrogenation to methanol in each embodiment is shown in Table 1.

[0056] Table 1. Specific surface area of ​​catalysts and performance of CO2 hydrogenation to methanol

[0057] As shown in Table 1, the coprecipitation temperature has a significant impact on catalyst performance. Example 1, using coprecipitation at 4℃, achieved a maximum specific surface area of ​​97.8 m². 2 / g, with a methanol selectivity as high as 98.9%, significantly better than the 73.5 m in Example 2. 2 / g and 63.2% and 59.2 m in Example 3. 2 / g and 46.0%. This indicates that low-temperature coprecipitation is beneficial for forming an indium oxide support with a high specific surface area, providing a good basis for copper dispersion and thus improving methanol selectivity.

[0058] The effect of indium oxide calcination temperature is demonstrated in the comparison of Examples 1, 4, 5, and 6. Example 1, calcined at 450°C, has a specific surface area of ​​97.8 m². 2 / g, with a methanol selectivity of up to 98.9%. Example 4 showed a specific surface area of ​​89.3 m² upon calcination at 350°C. 2 / g, methanol selectivity is 96.8%. Example 5 has a specific surface area of ​​83.6 m² when calcined at 550℃. 2 / g, methanol selectivity was 92.6%. In Example 6, the specific surface area decreased to 66.1 m² upon calcination at 650°C. 2 / g, with a methanol selectivity of 83.0%. These results indicate that calcination temperature affects the specific surface area and surface structure of indium oxide, thereby influencing the interaction between copper and indium oxide. Calcination at 450℃ yields a suitable specific surface area and an ideal interfacial structure.

[0059] The effect of copper loading is illustrated in the comparison of Examples 1, 7, and 8. In Example 1, the specific surface area was 97.8 m² when loaded with 10% copper. 2 / g, methanol selectivity reached 98.9%. Example 7 showed a specific surface area of ​​94.2 m² when loaded with 2% copper. 2 / g, methanol selectivity was 96.3%, but the low loading resulted in insufficient active sites and low conversion rate. In Example 8, the specific surface area was 75.5 m² when loaded with 20% copper. 2 / g, the methanol selectivity is 90.1%. Excessive loading leads to the aggregation of copper particles, which reduces the specific surface area and decreases the methanol selectivity.

[0060] The effect of copper roasting temperature is demonstrated in the comparison of Examples 1, 9, and 10. Example 1, roasted at 350°C, has a specific surface area of ​​97.8 m². 2 / g, methanol selectivity reached 98.9%. Example 9 showed a specific surface area of ​​89.3 m² upon calcination at 250°C. 2 / g, methanol selectivity was 88.9%, the calcination temperature was too low leading to incomplete copper reduction and low activity. Example 10 showed a specific surface area of ​​81.4 m² when calcined at 450℃. 2 / g, the methanol selectivity was 81.5%. Excessive calcination temperature caused copper particles to grow, the specific surface area to decrease, and the methanol selectivity to decrease significantly.

[0061] The catalyst prepared in Example 1 was subjected to long-term stability testing under the same reaction conditions for 100 hours. The results are as follows. Figure 2 As shown. By Figure 2 As can be seen, during the long-term evaluation of 100 hours, the catalyst of Example 1 showed good stability. The carbon dioxide conversion rate slowly decreased from the initial 5.5% to about 4.5%, and the methanol selectivity slowly decreased from the initial 98.9% to about 96.8%. Although the conversion rate and selectivity decreased slightly, they remained at a high level overall, and no rapid deactivation trend was observed.

[0062] The performance test results of the above embodiments show that the Cu / In₂O₃ catalyst provided by the present invention exhibits excellent catalytic performance in the hydrogenation of carbon dioxide to methanol. Among them, the catalyst prepared with a co-precipitation temperature of 4℃, an indium oxide calcination temperature of 450℃, a copper loading of 10 wt%, and a copper calcination temperature of 350℃ (Example 1) has the best performance, with a specific surface area of ​​97.8 m². 2 / g, with a methanol selectivity of up to 98.9% and a methanol yield of about 5.6%, which is significantly better than existing non-precious metal catalysts.

[0063] This invention optimizes the interfacial interaction between copper and indium oxide by systematically controlling key preparation parameters such as the co-precipitation temperature of indium oxide, the calcination temperature of indium oxide, the copper loading, and the calcination temperature of copper, providing an effective way to improve the methanol selectivity of catalysts.

[0064] This invention uses a low-temperature co-precipitation method to prepare indium oxide support, which is beneficial to enhance the interaction between the support and copper, thereby enhancing the carbon dioxide activation capacity and suppressing the reverse water gas side reaction.

[0065] The Cu / In₂O₃ catalyst prepared in this invention exhibits excellent catalytic performance in the hydrogenation of carbon dioxide to methanol. The reaction was carried out at a temperature of 280 °C, a pressure of 3 MPa, and a space velocity of 3000 mL·g⁻¹. -1 ·h -1 Under the specified conditions, the catalyst prepared by using a co-precipitation temperature of 4℃, an indium oxide calcination temperature of 450℃, a copper loading of 10 wt%, and a copper calcination temperature of 350℃ achieved a carbon dioxide conversion rate of 5.7% and a methanol selectivity of 98.9%, which is significantly better than existing non-precious metal catalysts.

[0066] The preparation method of this invention does not require precious metals, complex template agents, or multiple post-processing steps. It is simple to operate, low in cost, and easy to scale up industrially, and has good application prospects.

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a Cu / In₂O₃ catalyst with high methanol selectivity, characterized in that: include, Indium salt solution and precipitant solution were added dropwise to deionized water at 0-10℃, while the temperature of the reaction system was kept constant during the addition. After the addition was completed, an aging treatment was performed. The resulting precipitate was filtered, washed, dried, and then calcined in air to obtain indium oxide support. A copper salt was dissolved in deionized water to prepare an impregnation solution. The impregnation solution was loaded onto the indium oxide support using an equal-volume impregnation method. After standing and aging and drying, the solution was calcined under an inert or reducing atmosphere to obtain a Cu / In2O3 catalyst.

2. The preparation method of the high methanol selectivity Cu / In₂O₃ catalyst as described in claim 1, characterized in that: The indium salt is one or more of indium nitrate, indium chloride, or indium sulfate; The precipitant is one or more of ammonium carbonate, sodium carbonate, sodium hydroxide, urea, or ammonia water; the amount of the precipitant used is an excess amount to completely precipitate indium ions.

3. The method for preparing the high methanol selectivity Cu / In₂O₃ catalyst as described in claim 1 or 2, characterized in that: The aging process shall not exceed 24 hours; The process involves calcining in air at a temperature of 300-650°C for 2-6 hours. The settling and aging time shall not exceed 4 hours.

4. The preparation method of the high methanol selectivity Cu / In₂O₃ catalyst as described in claim 3, characterized in that: The copper salt is one or more of copper nitrate, copper chloride, copper acetate, or copper sulfate; The amount of copper salt added is configured such that the copper loading in the Cu / In2O3 catalyst is 1~20 wt%.

5. The method for preparing the high methanol selectivity Cu / In₂O₃ catalyst according to any one of claims 1, 2, and 4, characterized in that: The process involves calcining in an inert or reducing atmosphere at a temperature of 250-450°C for 2-6 hours.

6. A Cu / In₂O₃ catalyst with high methanol selectivity, characterized in that: Prepared by the preparation method according to any one of claims 1 to 5; The catalyst comprises an indium oxide support and copper nanoparticles loaded on its surface. The copper nanoparticles are highly dispersed on the surface of the indium oxide and form a strongly interacting interface structure with the indium oxide.

7. The high methanol selectivity Cu / In₂O₃ catalyst as described in claim 6, characterized in that: The copper loading is 1~20wt%.

8. The high methanol selectivity Cu / In₂O₃ catalyst as described in claim 6, characterized in that: The catalyst has a specific surface area of ​​70~100 m². 2 / g.

9. The application of the high methanol selectivity Cu / In2O3 catalyst as described in any one of claims 6 to 8 in the reaction of carbon dioxide hydrogenation to methanol.

10. The application as described in claim 9, characterized in that: A mixture of hydrogen and carbon dioxide is introduced into the highly methanol-selective Cu / In₂O₃ catalyst at a reaction temperature of 200–300 °C, a reaction pressure of 1–5 MPa, and a gas hourly space velocity of 3000–20000 mL·g. -1 ·h -1 Under the given reaction conditions, hydrogenation is carried out to obtain methanol.

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