Noble metal supported catalysts, methods of making and using same

Abstract

The application relates to the technical field of synthesizing methanol by catalyzing carbon dioxide hydrogenation, and discloses a noble metal supported catalyst, a preparation method and application. The noble metal supported catalyst comprises a carrier and a metal active component, the carrier is activated carbon, and the metal active component is a rhodium component and / or a ruthenium component. According to the technical scheme of the application, the rhodium component and the ruthenium component with strong catalytic hydrogenation activity are highly dispersed on the activated carbon which is not easy to collapse and easy to maintain the original structure, so that a catalyst with high catalytic activity in the application of synthesizing methanol by catalyzing carbon dioxide hydrogenation is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalytic synthesis of methanol from carbon dioxide and hydrogen, and in particular to a noble metal supported catalyst, a preparation method and an application thereof. BACKGROUND

[0002] Global warming is becoming increasingly prominent, and the massive emission of greenhouse gases is one of the main causes of global warming. At present, the problem of industrial carbon emission with carbon dioxide as the main component has attracted more and more attention, and governments and enterprises are trying to store and consume carbon dioxide on a large scale. In terms of the consumption and utilization of carbon dioxide, converting carbon dioxide into low-carbon alcohol liquid synthetic fuels and other high-value-added products through chemical reactions can be considered as one of the most promising ways to reduce carbon dioxide emissions today. At the same time, methanol is an important basic chemical raw material, which can be used as a substitute fuel, and can also be used to synthesize dimethyl ether, light olefins, aromatic hydrocarbons and acetic acid and other chemicals. Therefore, using the catalytic hydrogenation process of CO2 to generate methanol, which is a high-value-added product, is one of the feasible ways to promote the efficient utilization of carbon dioxide resources and achieve carbon neutrality.

[0003] The catalysts for synthesizing methanol from carbon dioxide and hydrogen include copper-based catalysts, noble metal supported catalysts and composite support catalysts. Among them, the noble metal supported catalysts, because the outer d orbitals of noble metals such as platinum (Pt) and gold (Au) are not filled, the p orbital electron pairs of C and O in CO2 can enter the outer d orbitals of the above noble metals, which macroscopically means that CO2 is more easily adsorbed on noble metal atoms, increasing the probability of effective collision in hydrogenation conversion reactions, thereby improving the conversion efficiency of CO2. However, the noble metal catalysts have problems such as easy sintering, short service life and low selectivity of target products.

[0004] In the existing research, patent application CN114029063A discloses a catalyst for preparing methanol from carbon dioxide and hydrogen and a preparation method thereof. The composition of the catalyst includes metal copper, metal zinc, metal zirconium, metal additives and carbon materials. The catalyst has good stability in the selective hydrogenation of carbon dioxide and hydrogen to prepare methanol, but the metal utilization rate is low, the amount is large, and the activity and selectivity still have room for improvement; patent application CN105727942A discloses a palladium / carbon nanotube catalyst and its preparation and application. The catalyst is prepared by depositing palladium nanoparticles on the inside of carbon nanotubes. The catalyst uses carbon nanotubes as a carrier, which is expensive, has a narrow source, and has a complex pre-treatment process. In the pre-treatment process, the physical structure is more prone to collapse, and the pore structure is not easy to maintain. Therefore, the CO X conversion rate is low, and the selectivity of methanol is low.

[0005] Therefore, it is urgent to develop a catalyst to solve the problems of metal utilization rate, low selectivity, easy collapse and difficulty in maintaining the original structure. SUMMARY

[0006] The present application aims to overcome the problems of easy sintering, short service life and low selectivity of noble metal catalysts in reaction, and easy collapse in CO2 hydrogenation reaction in fixed bed and difficulty in maintaining the original structure, and provides a noble metal supported catalyst, a preparation method and application. The present application greatly improves the hydrophobicity of the catalyst, thereby improving the activity and methanol selectivity of the catalyst.

[0007] To achieve the above-mentioned purpose, the present application provides a noble metal supported catalyst, which comprises a carrier and a metal active component, wherein the carrier is activated carbon, and the metal active component is a rhodium component and / or a ruthenium component.

[0008] Preferably, the specific surface area of the activated carbon is 50-300 m 2 / g, and the porosity is 0.1-0.5 m 3 / g.

[0009] Preferably, the content of the metal active component is 1-10 parts by weight relative to 100 parts by weight of the carrier.

[0010] The second aspect of the present application provides a preparation method of a noble metal supported catalyst, which comprises loading a water-soluble rhodium salt and / or a water-soluble ruthenium salt on activated carbon, and then calcining.

[0011] Preferably, the process of loading a water-soluble rhodium salt or a water-soluble ruthenium salt on activated carbon comprises:

[0012] providing a solution containing a water-soluble rhodium salt and / or a water-soluble ruthenium salt, wherein the solvent is ethanol and water;

[0013] adding the solution containing a water-soluble rhodium salt and / or a water-soluble ruthenium salt drop by drop to activated carbon under stirring, and adding the next drop after the last drop is completely absorbed by the activated carbon.

[0014] Preferably, the specific surface area of the activated carbon is 50-300 m 2 / g, and the porosity is 0.1-0.5 m 3 / g.

[0015] Preferably, the water-soluble rhodium salt is rhodium chloride and / or rhodium nitrate; and the water-soluble ruthenium salt is ruthenium chloride and / or ruthenium nitrate.

[0016] Preferably, in the solvent, the volume ratio of ethanol to water is (0.1-0.5):1.

[0017] Preferably, the concentration of the metal salt in the solution containing water-soluble rhodium salt and / or water-soluble ruthenium salt is 0.01-0.05 mol / L.

[0018] Preferably, the method further includes: before calcination, covering activated carbon loaded with water-soluble rhodium salt and / or water-soluble ruthenium salt with tin foil and punching small holes, and placing it in an oven at 70-90°C for 1-24 hours.

[0019] Preferably, the calcination process is carried out in the presence of a protective gas, and the calcination conditions include: a temperature of 550-800℃ and a time of 4-24h.

[0020] The third aspect of this invention provides the application of the above-mentioned noble metal supported catalyst in the catalytic hydrogenation of carbon dioxide to methanol.

[0021] Preferably, the reaction of carbon dioxide hydrogenation to methanol is carried out in a fixed-bed reactor, and the noble metal supported catalyst is filled into the reaction tube of the fixed-bed reactor after being ground and sieved.

[0022] Preferably, the particle size of the catalyst particles after grinding and sieving is 10-200 nm.

[0023] According to the noble metal supported catalyst of the present invention, the use of noble metals with higher catalytic hydrogenation activity, such as rhodium (Rh) and ruthenium (Ru), as well as activated carbon with larger specific surface area and porosity, can help to prevent collapse, maintain the original structure, and thus increase service life. According to the preparation method of the present invention, it can help to achieve more uniform dispersion of metal particles and resistance to sintering. In the application process, the noble metal supported catalyst of the present invention has high catalytic activity when used for the hydrogenation of carbon dioxide to methanol, and can obtain high methanol selectivity and CO2 conversion rate. Detailed Implementation

[0024] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] The noble metal supported catalyst of the present invention comprises a support and a metal active component, wherein the support is activated carbon and the metal active component is a rhodium component and / or a ruthenium component.

[0027] In the noble metal supported catalyst of the present invention, during the catalytic hydrogenation reaction, in order to make the noble metal supported catalyst less prone to collapse and maintain its original structure, the specific surface area of ​​the activated carbon is preferably 50-300 m². 2 / g, more preferably 100-300m 2 / g; the preferred porosity is 0.1-0.5m 3 / g, more preferably 0.15-0.45m 3 / g.

[0028] In the noble metal supported catalyst of the present invention, the content of the metal active component relative to 100 parts by weight of the support can be 1-10 parts by weight, preferably 1-5 parts by weight.

[0029] In some embodiments of the noble metal supported catalyst according to the present invention, the active component may be a combination of rhodium and ruthenium components, and the molar ratio of rhodium to ruthenium components may be 1:(0-1), preferably 1:(0.5-1).

[0030] In some embodiments of the noble metal supported catalyst according to the present invention, the active component may be a rhodium component.

[0031] In some embodiments of the noble metal supported catalyst according to the present invention, the active component may be a ruthenium component.

[0032] In some embodiments, the noble metal supported catalyst comprises a support and a metal active component, wherein the support may be activated carbon, and the metal active component may be a rhodium component and / or a ruthenium component; the specific surface area of ​​the activated carbon may be 50-300 m². 2 / g, porosity can be 0.1-0.5m 3 / g; relative to 100 parts by weight of the carrier, the content of the metal active component can be 1-10 parts by weight.

[0033] In other embodiments, the noble metal supported catalyst comprises a support and a metal active component, wherein the support may be activated carbon, and the metal active component may be a combination of rhodium and ruthenium components, with a molar ratio of rhodium to ruthenium of 1:(0-1); the specific surface area of ​​the activated carbon may be 50-300 m². 2 / g, porosity can be 0.1-0.5m 3 / g; relative to 100 parts by weight of the carrier, the content of the metal active component can be 1-10 parts by weight.

[0034] In other embodiments, the noble metal supported catalyst includes a support and a metal active component, wherein the support may be activated carbon, and the metal active component may be a rhodium component; the specific surface area of ​​the activated carbon may be 50-300 m². 2 / g, porosity can be 0.1-0.5m 3 / g; relative to 100 parts by weight of the carrier, the content of the metal active component can be 1-10 parts by weight.

[0035] In other embodiments, the noble metal supported catalyst comprises a support and a metal active component, wherein the support may be activated carbon, and the metal active component may be a ruthenium component; the specific surface area of ​​the activated carbon may be 50-300 m². 2 / g, porosity can be 0.1-0.5m 3 / g; relative to 100 parts by weight of the carrier, the content of the metal active component can be 1-10 parts by weight.

[0036] This invention also provides a method for preparing a noble metal supported catalyst, which involves loading water-soluble rhodium salts and / or water-soluble ruthenium salts onto activated carbon, followed by calcination. The noble metal supported catalyst prepared by this method exhibits good dispersion of the metal particles as the active component and resistance to sintering. The activated carbon support is not easily collapsed and retains its original structure. When used for the hydrogenation of carbon dioxide to methanol, it demonstrates high catalytic activity and achieves high methanol selectivity and CO2 conversion rate.

[0037] In the method described in this invention, in order to ensure that the active metal component is more uniform on the support, the process of loading water-soluble rhodium salt or water-soluble ruthenium salt onto activated carbon includes:

[0038] A solution containing a water-soluble rhodium salt and / or a water-soluble ruthenium salt is provided, wherein the solvent may be ethanol and water;

[0039] Under stirring conditions, the solution containing water-soluble rhodium salt and / or water-soluble ruthenium salt is added dropwise to activated carbon, and the next drop is added only after the previous drop has been completely absorbed by the activated carbon.

[0040] In some embodiments, during the catalytic hydrogenation reaction, to prevent the noble metal-supported catalyst from collapsing and to maintain its original structure, the specific surface area of ​​the activated carbon is preferably 50-300 m². 2 / g, more preferably 100-300m 2 / g; the preferred porosity is 0.1-0.5m 3 / g, more preferably 0.15-0.45m 3 / g.

[0041] In some embodiments, the water-soluble rhodium salt may be rhodium chloride and / or rhodium nitrate; the water-soluble ruthenium salt may be ruthenium chloride and / or ruthenium nitrate.

[0042] In some embodiments, the volume ratio of ethanol to water in the solvent can be (0.1-0.5):1, preferably (0.1-0.4):1.

[0043] In a preferred embodiment, the concentration of the metal salt in the solution containing water-soluble rhodium salt and / or water-soluble ruthenium salt can be 0.01-0.05 mol / L, preferably 0.01-0.04 mol / L.

[0044] In some embodiments, to ensure that the water and ethanol contained in the solution containing water-soluble rhodium salt and / or water-soluble ruthenium salt evaporate completely and to utilize capillary action to uniformly distribute the active metal components on the structure of the activated carbon, the method further includes: before calcination, covering the activated carbon loaded with water-soluble rhodium salt and / or water-soluble ruthenium salt with tin foil and punching small holes, preferably placing it in an oven at 70-90°C for 1-24 hours, more preferably placing it in an oven at 75-85°C for 11-13 hours.

[0045] In some embodiments, the calcination process is carried out in the presence of a protective gas, and the calcination conditions may include: a temperature of 550-800°C, preferably 600-700°C; and a time of 4-24 hours, preferably 6-18 hours.

[0046] In some embodiments, the protective gas used during the calcination process can be a conventional protective gas in the art. Preferably, to prevent the activated carbon carrier from burning completely due to contact with air in the muffle furnace and to ensure maximum preservation of the activated carbon structure, the protective gas used can be at least one of nitrogen, argon, and helium, with nitrogen being the most preferred. Preferably, the purity of the nitrogen is 99.0%-99.9%.

[0047] In some embodiments, a solution containing a water-soluble rhodium salt and a water-soluble ruthenium salt is provided, wherein the solvent is ethanol and water, the water-soluble rhodium salt is rhodium chloride and / or rhodium nitrate; and the water-soluble ruthenium salt is ruthenium chloride and / or ruthenium nitrate. In the solvent, the molar ratio of the water-soluble rhodium salt to the water-soluble ruthenium salt is (0-1):1, and the volume ratio of ethanol to water is (0.1-0.5):1; the concentration of the metal salt in the solution containing the water-soluble rhodium salt and the water-soluble ruthenium salt is 0.01-0.05 mol / L. Under stirring conditions, the solution containing the water-soluble rhodium salt and the water-soluble ruthenium salt is added dropwise to activated carbon, and the next drop is added only after the previous drop has been completely absorbed by the activated carbon. The specific surface area of ​​the activated carbon is 50-300 m² / L. 2 / g, porosity 0.1-0.5m 3 / g. Activated carbon loaded with water-soluble rhodium and ruthenium salts is covered with tin foil with small holes punched in it and placed in an oven at 70-90℃ for 1-24 hours. Then, it is calcined in the presence of a protective gas under the following conditions: temperature 550-800℃, time 4-24h.

[0048] In other embodiments, a solution containing a water-soluble rhodium salt is provided, wherein the solvent is ethanol and water, and the water-soluble rhodium salt is rhodium chloride and / or rhodium nitrate. In the solvent, the volume ratio of ethanol to water is (0.1-0.5):1; the concentration of the metal salt in the solution containing the water-soluble rhodium salt is 0.01-0.05 mol / L. Under stirring conditions, the solution containing the water-soluble rhodium salt is added dropwise to activated carbon, and the next drop is added only after the previous drop has been completely absorbed by the activated carbon. The specific surface area of ​​the activated carbon is 50-300 m² / g. 2 / g, porosity 0.1-0.5m 3 / g. Activated carbon loaded with water-soluble rhodium salts is covered with tin foil and perforated, then placed in an oven at 70-90℃ for 1-24 hours. It is then calcined in the presence of a protective gas under the following conditions: temperature 550-800℃, time 4-24h.

[0049] In some embodiments, a solution containing a water-soluble ruthenium salt is provided, wherein the solvent is ethanol and water, and the water-soluble ruthenium salt is ruthenium chloride and / or ruthenium nitrate. In the solvent, the volume ratio of ethanol to water is (0.1-0.5):1; the concentration of the metal salt in the solution containing the water-soluble ruthenium salt is 0.01-0.05 mol / L. Under stirring conditions, the solution containing the water-soluble ruthenium salt is added dropwise to activated carbon, and the next drop is added only after the previous drop has been completely absorbed by the activated carbon. The specific surface area of ​​the activated carbon is 50-300 m² / g. 2 / g, porosity 0.1-0.5m 3 / g. Activated carbon loaded with water-soluble ruthenium salt is covered with tin foil with small holes punched in it and placed in an oven at 70-90℃ for 1-24 hours. Then, it is calcined in the presence of a protective gas under the following conditions: temperature 550-800℃, time 4-24h.

[0050] This invention also provides the application of the above-mentioned noble metal supported catalyst in the catalytic hydrogenation of carbon dioxide to methanol. The use of the noble metal supported catalyst for the hydrogenation of carbon dioxide to methanol exhibits high catalytic activity and can achieve high methanol selectivity and CO2 conversion rate.

[0051] In the application described in this invention, the reaction of carbon dioxide hydrogenation to synthesize methanol is carried out in a fixed-bed reactor. In order to ensure that the structural strength of the catalyst is maintained and to avoid excessive pressure difference or even blockage in the reaction system caused by gas compression in subsequent reaction experiments, the noble metal supported catalyst is filled into the reaction tube of the fixed-bed reactor after grinding and sieving.

[0052] In some embodiments, the particle size of the catalyst particles after grinding and sieving can be 10-200 nm, preferably 50-180 nm.

[0053] In other embodiments, the reaction conditions for the catalytic hydrogenation of carbon dioxide to methanol may include: introducing CO2 and H2, wherein the volume concentration of CO2 is 10%-30%, preferably 15%-25%; the volume concentration of H2 is 30%-90%, preferably 45%-75%; the pressure is 0.1-2.0 MPa, preferably 0.4-1.8 MPa; the temperature is 300-800℃, preferably 350-650℃; and the time is 2-12 h, preferably 4-8 h. In this document, pressure refers to gauge pressure.

[0054] The following examples further illustrate the noble metal supported catalyst, its preparation method, and its application according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0055] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0056] Example 1

[0057] (1) Dissolve 0.03g rhodium nitrate and 0.03g ruthenium nitrate in 5mL of a mixed solvent of ethanol and water in a ratio of 0.1:1 to prepare a solution; under stirring conditions, add the solution dropwise to 0.98g activated carbon, and add the next drop only after the previous drop has been completely absorbed by the activated carbon, until all the salt solution has been absorbed by the activated carbon.

[0058] (2) Cover the activated carbon loaded with rhodium nitrate and ruthenium nitrate with tin foil and make small holes, place it in an oven at 75°C for 13 hours; then place it in a calcination tube and calcinate it under N2 protection. Slowly heat the dried mixture to 600°C and keep it for 18 hours.

[0059] (3) After extruding the calcined product, grind and sieve it into catalyst particles of 50-180nm. Take 0.2g of catalyst particles and then fill them into the fixed bed reaction tube.

[0060] (4) CO2 and H2 are mixed to form a feed gas, and the pressure is adjusted to 1 MPa. The volume concentration of CO2 is 15% and the volume concentration of H2 is 45%. This feed gas is passed through a reaction tube containing a catalyst in a fixed bed, and the fixed bed is heated to 350°C and maintained for 6 hours. The product after the reaction is detected by online gas chromatography to obtain the carbon dioxide conversion rate and the selectivity of the target product. The CO2 conversion rate is calculated by the N2-internal standard method, and the selectivity and yield of methanol are calculated by the C-based internal normalization method. The calculation data are shown in Table 1.

[0061] Example 2

[0062] (1) Dissolve 0.03g of rhodium chloride in 5mL of a mixed solvent of ethanol and water in a ratio of 0.2:1 to prepare a solution; under stirring conditions, add the solution dropwise to 0.98g of activated carbon, and add the next drop only after the previous drop has been completely absorbed by the activated carbon, until all the salt solution has been absorbed by the activated carbon.

[0063] (2) Cover the activated carbon loaded with rhodium chloride with tin foil and make small holes, place it in an oven at 80°C for 12 hours; then place it in a calcination tube and calcinate it under N2 protection. Slowly heat the dried mixture to 650°C and keep it for 12 hours.

[0064] (3) After extruding the calcined product, grind and sieve it into catalyst particles of 80-180 nm. Take 0.2 g of catalyst particles and then fill them into the fixed bed reaction tube.

[0065] (4) CO2 and H2 are mixed to form a feed gas and introduced into the system. The pressure is adjusted to 0.4 MPa. The volume concentration of CO2 is 20% and the volume concentration of H2 is 75%. This feed gas is passed through a reaction tube containing a catalyst in a fixed bed. The fixed bed is heated to 500°C and maintained for 6 hours. The product after the reaction is detected by online gas chromatography to obtain the carbon dioxide conversion rate and the selectivity of the target product. The CO2 conversion rate is calculated by the N2-internal standard method, and the selectivity and yield of methanol are calculated by the C-based internal normalization method. The calculation data are shown in Table 1.

[0066] Example 3

[0067] (1) Dissolve 0.03g of ruthenium chloride in 5mL of a mixed solvent of ethanol and water in a ratio of 0.4:1 to prepare a solution; under stirring conditions, add the solution dropwise to 0.98g of activated carbon, and add the next drop only after the previous drop has been completely absorbed by the activated carbon, until all the salt solution has been absorbed by the activated carbon.

[0068] (2) Cover the activated carbon loaded with ruthenium chloride with tin foil and make small holes, place it in an oven at 85°C for 11 hours; then place it in a calcination tube and calcinate it under N2 protection. Slowly heat the dried mixture to 700°C and keep it for 6 hours.

[0069] (3) After extruding the calcined product, grind and sieve it into catalyst particles of 80-180 nm. Take 0.2 g of catalyst particles and then fill them into the fixed bed reaction tube.

[0070] (4) CO2 and H2 are mixed to form a feed gas and introduced into the system. The pressure is adjusted to 1.8 MPa. The volume concentration of CO2 is 25% and the volume concentration of H2 is 60%. This feed gas is passed through a reaction tube containing a catalyst in a fixed bed. The fixed bed is heated to 650°C and maintained for 6 hours. The product after the reaction is detected by online gas chromatography to obtain the carbon dioxide conversion rate and the selectivity of the target product. The CO2 conversion rate is calculated by the N2-internal standard method, and the selectivity and yield of methanol are calculated by the C-based internal normalization method. The calculation data are shown in Table 1.

[0071] Example 4

[0072] The noble metal supported catalyst was prepared according to the method in Example 1, except that the operation of "adding the solution dropwise to activated carbon under stirring, and adding the next dropwise only after the previous drop has been completely absorbed by the activated carbon, until all the salt solution has been absorbed by the activated carbon" was replaced with "directly adding the solution to the activated carbon". The calculation data are shown in Table 1.

[0073] Example 5

[0074] The noble metal supported catalyst was prepared according to the method in Example 1, except that the operation of "covering the rhodium chloride-loaded activated carbon with tin foil and punching small holes" was replaced by "directly placing the rhodium chloride-loaded activated carbon in an oven at 75°C for 13 hours". The calculated data are shown in Table 1.

[0075] Comparative Example 1

[0076] The noble metal supported catalyst was prepared according to the method in Example 1, except that 0.03 g of rhodium nitrate and 0.03 g of ruthenium nitrate were replaced with 0.06 g of silver chloride. Calculation data are shown in Table 1.

[0077] Comparative Example 2

[0078] The noble metal supported catalyst was prepared according to the method in Example 1, except that 0.98 g of activated carbon was replaced with 0.98 g of pure silica molecular sieve support. Calculation data are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] As can be seen from the results in Table 1, the noble metal supported catalysts of Examples 1-3 can be prepared by the preparation method of the present invention. The application of these catalysts in the catalytic hydrogenation of carbon dioxide to methanol yields high methanol selectivity and CO2 conversion rate.

[0083] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A noble metal supported catalyst, characterized in that, The noble metal supported catalyst includes a support and a metal active component, wherein the support is activated carbon and the metal active component is a rhodium component and / or a ruthenium component; The specific surface area of ​​the activated carbon is 50-300 m². 2 / g, porosity 0.1-0.5m 3 / g; The content of the metal active component is 1-10 parts by weight relative to 100 parts by weight of the carrier; The method for preparing the noble metal supported catalyst involves loading water-soluble rhodium salts and / or water-soluble ruthenium salts onto activated carbon, followed by calcination. The process of loading water-soluble rhodium salts or water-soluble ruthenium salts onto activated carbon includes: A solution containing a water-soluble rhodium salt and / or a water-soluble ruthenium salt is provided, wherein the solvent is ethanol and water; Under stirring conditions, the solution containing water-soluble rhodium salt and / or water-soluble ruthenium salt is added dropwise to activated carbon, and the next drop is added only after the previous drop has been completely absorbed by the activated carbon. The method further includes: before calcination, covering activated carbon loaded with water-soluble rhodium salt and / or water-soluble ruthenium salt with tin foil and punching small holes, and placing it in an oven at 70-90°C for 1-24 hours.

2. The noble metal supported catalyst according to claim 1, characterized in that, The water-soluble rhodium salt is rhodium chloride and / or rhodium nitrate; the water-soluble ruthenium salt is ruthenium chloride and / or ruthenium nitrate.

3. The noble metal supported catalyst according to claim 1 or 2, characterized in that, In the solvent, the volume ratio of ethanol to water is (0.1-0.5):

1.

4. The noble metal supported catalyst according to claim 1 or 2, characterized in that, The concentration of the metal salt in the solution containing water-soluble rhodium salt and / or water-soluble ruthenium salt is 0.01-0.05 mol / L.

5. The noble metal supported catalyst according to claim 1 or 2, characterized in that, The calcination process is carried out in the presence of a protective gas, and the calcination conditions include: a temperature of 550-800℃ and a time of 4-24h.

6. The application of the noble metal supported catalyst according to any one of claims 1-5 in the catalytic hydrogenation of carbon dioxide to methanol.

7. The application according to claim 6, characterized in that, The reaction of carbon dioxide hydrogenation to synthesize methanol is carried out in a fixed-bed reactor, and the noble metal supported catalyst is filled into the reaction tube of the fixed-bed reactor after being ground and sieved.

8. The application according to claim 6, characterized in that, The particle size of the catalyst particles after grinding and sieving is 10-200 nm.

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