Precious metal loaded indium zirconium carbon composite material and preparation method thereof and method for preparing methanol by hydrogenating carbon dioxide

Abstract

The present invention relates to the field of catalysts, and discloses a noble metal-loaded indium zirconium carbon composite material, a preparation method thereof, and a method for preparing methanol by hydrogenating carbon dioxide. The method comprises the following steps: (1) providing a mixed solution containing an In salt, a Zr salt, a carbon source, and water; (2) reacting the mixed solution in a supercritical state of water to obtain an In zirconium carbon composite material; (3) mixing the In zirconium carbon composite material, an organic solvent, and a noble metal salt to obtain an organic mixed solution, and then reacting the solution, wherein the reaction is carried out in a supercritical state of the organic solvent; (4) heat-treating the product obtained by the reaction in step (3); based on the total amount of metal, the molar composition of the In salt and the Zr salt is as follows: In: 40-95%, Zr: 5-60%. The present invention adopts a simple and efficient supercritical fluid deposition technology to prepare the noble metal-loaded In zirconium carbon composite material, which has excellent catalytic performance in the CO2 methanol production reaction, high reaction activity, and high methanol selectivity.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a noble metal-loaded indium zirconium-carbon composite material and a preparation method thereof, and a method for preparing methanol by hydrogenating carbon dioxide. Background Art

[0002] Methanol is an important raw material for chemicals and a substitute for fossil fuels. The production of methanol by reacting CO2 with H2 from renewable energy is not only an effective way to solve greenhouse gas control but also an effective way to replace fossil fuels.

[0003] Among the numerous catalysts used in CO2 hydrogenation to produce methanol, modified copper-based catalysts have long been studied and applied. Cu-based catalysts for conventional syngas-to-methanol conversion have been extensively studied in CO2-to-methanol conversion. However, high side reaction (RWGS) activity, H2O-induced sintering of the active phase, and poor stability have limited their further application. In other catalytic systems, the high cost of noble metals and the low activity and migration of ZnO have also limited their further application in this field. In2O3 has attracted widespread attention due to its moderate CO2 and CO adsorption capacity, significantly superior methanol selectivity to Cu, Co, and noble metal catalysts, and higher catalytic activity than ZnO catalysts. In the CO2 hydrogenation-to-methanol reaction, indium-based catalysts exhibit high methanol selectivity, but their CO2 conversion is low. Therefore, research on modifying indium-based catalysts is needed to improve CO2 conversion while maintaining high methanol selectivity. The design and development of more efficient modified indium oxide catalysts is crucial for the industrial application of CO2 hydrogenation to methanol, although significant improvements in catalytic performance remain significant challenges. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of complex preparation process, poor repeatability, low catalyst activity and poor reaction stability of CO2 hydrogenation catalyst in the prior art, and to provide a precious metal-loaded indium zirconium carbon composite material and its preparation method and a method for preparing methanol by hydrogenating carbon dioxide. The precious metal-loaded indium zirconium carbon composite material has excellent catalytic performance, high reaction activity, high selectivity of target product, good reaction stability and very low deactivation rate.

[0005] In order to achieve the above object, the present invention provides a method for preparing a noble metal-loaded indium zirconium-carbon composite material, which comprises the following steps:

[0006] (1) providing a mixed solution containing an In salt, a Zr salt, a carbon source, and water;

[0007] (2) reacting the mixed solution under a supercritical state of water to obtain an indium zirconium carbon composite material;

[0008] (3) mixing the indium zirconium carbon composite material, an organic solvent and a noble metal salt to obtain an organic mixed solution, and then reacting the organic solvent under a supercritical state;

[0009] (4) heat-treating the product obtained by the reaction in step (3);

[0010] Based on the total amount of metals, the molar composition of the In salt and the Zr salt is: In: 40-95%, Zr: 5-60%.

[0011] The second aspect of the present invention provides a noble metal-loaded indium-zirconium-carbon composite material prepared by the preparation method described in the first aspect.

[0012] A third aspect of the present invention provides a method for preparing methanol by hydrogenating carbon dioxide, the method comprising:

[0013] Under the conditions of producing methanol by hydrogenation of carbon dioxide, carbon dioxide and hydrogen are contacted in the presence of a catalyst; the catalyst is the noble metal-supported indium zirconium-carbon composite material provided in the second aspect;

[0014] Preferably, the conditions for the carbon dioxide hydrogenation reaction to produce methanol include: reaction pressure of 0.3MPa-8MPa, reaction temperature of 100℃-500℃, volume space velocity of 1500h -1 -40000h -1 , the H2 / CO2 molar ratio is 1-7.

[0015] Through the above technical solution, the beneficial effects obtained by the present invention are as follows:

[0016] (1) The present invention adopts a simple and efficient supercritical fluid deposition technology. By adjusting the temperature and pressure, the In and Zr precursors are instantly supersaturated in the supercritical solution, forming a large number of crystal nuclei, and further growing the indium zirconium carbon composite material with adjustable particle size and morphology for the reaction.

[0017] (2) The active components formed by the supercritical fluid deposition technology of the present invention have a fast nucleation speed, uniform dispersion, high nucleation rate and low energy consumption.

[0018] (3) The noble metal-loaded indium zirconium carbon composite material provided by the present invention has high methanol selectivity in a fixed bed reactor, and has the advantages of excellent catalytic performance, high reaction activity, high selectivity of target products, good reaction stability, and low deactivation rate. DETAILED DESCRIPTION

[0019] The endpoints of the ranges and any values ​​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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0020] A first aspect of the present invention provides a method for preparing a noble metal-loaded indium zirconium-carbon composite material, comprising the following steps:

[0021] (1) providing a mixed solution containing an In salt, a Zr salt, a carbon source, and water;

[0022] (2) reacting the mixed solution under a supercritical state of water to obtain an indium zirconium carbon composite material;

[0023] (3) mixing the indium zirconium carbon composite material, an organic solvent and a noble metal salt to obtain an organic mixed solution, and then reacting the organic solvent under a supercritical state;

[0024] (4) heat-treating the product obtained by the reaction in step (3);

[0025] Based on the total amount of metals, the molar composition of the In salt and the Zr salt is: In: 40-95%, Zr: 5-60%.

[0026] According to the present invention, supercritical water has strong reactivity and broad solubility. The supercritical state of the organic solvent helps accelerate mass transfer and increase reaction rate. The solubility of metal oxides in the supercritical water environment is low, resulting in a high nucleation rate, which is conducive to nanoparticle synthesis. Carrying out the reaction in a supercritical state causes the In and Zr precursors to instantly reach a supersaturated state in the supercritical solution, forming a large number of crystal nuclei, which further grow the InZrC composite material with adjustable particle size and morphology used in the reaction.

[0027] According to the present invention, by introducing a noble metal component into the indium zirconium carbon composite material, the dissociation of hydrogen is facilitated, thereby improving the CO2 conversion rate.

[0028] According to a preferred embodiment of the present invention, the molar composition of the In salt and the Zr salt, calculated as elements, based on the total amount of metals, is: In: 60-90%, Zr: 10-40%. Under the above preferred conditions, the catalyst activity is improved.

[0029] According to a preferred embodiment of the present invention, the total concentration of the In salt and the Zr salt in the mixed solution is 0.1-4 mol / L, more preferably 0.2-0.8 mol / L. Under the above preferred conditions, the catalyst reaction performance is improved.

[0030] In the present invention, the selection range for the specific types of In salts and Zr salts is relatively wide, preferably soluble salts of In and Zr, wherein the soluble salts are inorganic salts and / or organic matter; preferably, the inorganic salts are selected from nitrates, sulfates, acetates, and chlorides; and the organic matter is a metal alkoxide.

[0031] According to a preferred embodiment of the present invention, the mass ratio of the total amount of In salt and Zr salt to the carbon source in the mixed solution is 1-2:1, preferably 1.1-1.9:1.

[0032] According to the present invention, there is no specific limitation on the type of the carbon source, as long as carbon can be provided. Preferably, the carbon source is selected from at least one of starch, maltose, sucrose, glucose, cellulose, citric acid, fumaric acid, maleic acid, succinic acid, malic acid, tartaric acid, gluconic acid, terephthalic acid, pyridinedicarboxylic acid, ethylenediaminetetraacetic acid and trimesic acid; more preferably, at least one of sucrose, maleic acid, terephthalic acid, pyridinedicarboxylic acid and tartaric acid.

[0033] According to a preferred embodiment of the present invention, the mixed solution further contains an oxidant, preferably H2O2, and preferably provided in the form of a solution. By introducing the oxidant, the oxidizing property of supercritical water can be improved.

[0034] According to a preferred embodiment of the present invention, based on the total mass of the mixed solution, the amount of the oxidant is 0.1-1% by mass, more preferably 0.2-0.6% by mass.

[0035] In the present invention, there is no particular limitation on the mixing method and order of the mixed solution. The In salt, Zr salt and carbon source can be dissolved in water first, and then the oxidant is introduced. Alternatively, the In salt, Zr salt and oxidant can be dissolved in water first, and then the carbon source is added. The solvent water can be introduced in any of the above processes, as long as the total amount of water in the mixed solution can meet the concentration requirements of each component therein. For example, the solvent water in the mixed solution can be introduced separately as a solvent for the In salt, Zr salt and oxidant, or can be added uniformly. Preferably, the method of providing the mixed solution includes: dissolving the In salt and Zr salt in water, adding the carbon source, and then adding the oxidant and water.

[0036] According to a preferred embodiment of the present invention, the reaction conditions in step (2) include: temperature of 400-600°C; reaction pressure of 23-45 MPa; reaction time of 1-200 min; preferably, temperature of 450-520°C; reaction pressure of 25-35 MPa; reaction time of 20-150 min.

[0037] According to a preferred embodiment of the present invention, the method further includes separating the reaction product in step (2) to obtain an indium zirconium carbon composite material; specifically, the separation process includes: reducing the pressure and cooling the reaction system, filtering it to achieve gas-solid-liquid separation, and the separated solid is the indium zirconium carbon composite material.

[0038] According to a preferred embodiment of the present invention, the mixed solution is added to an autoclave, and then the temperature and pressure are increased to the supercritical state of water to carry out the reaction; after the reaction is completed, the pressure is released and cooled to achieve gas-solid-liquid separation, and the residual solid in the autoclave is the indium zirconium carbon composite material.

[0039] According to a preferred embodiment of the present invention, the noble metal in the noble metal salt is selected from at least one of gold, silver, ruthenium, rhodium, palladium, osmium, iridium, and platinum, more preferably at least one of platinum, palladium, ruthenium, and rhodium, and most preferably palladium. The use of a palladium-supported indium-zirconium-carbon composite material facilitates enhancing the active sites of the catalyst.

[0040] In the present invention, the noble metal salt can be selected from a wide range of noble metal salts. Preferably, the noble metal salt can be selected from at least one of noble metal nitrates, sulfates, and chlorides. For example, when the noble metal is palladium, the palladium salt can be selected from at least one of palladium nitrate, palladium dichloride, palladium sulfate, potassium tetrachloropalladate, sodium tetrachloropalladate, potassium hexachloropalladate, and sodium hexachloropalladate. Preferably, the amount of the noble metal salt is such that the molar ratio of In to the noble metal element in the resulting noble metal-loaded indium zirconium-carbon composite material, calculated as the elements, is 1:0.001-0.3, more preferably 1:0.005-0.25.

[0041] According to a preferred embodiment of the present invention, the organic solvent is selected from alcohols, preferably methanol and / or ethanol.

[0042] According to a preferred embodiment of the present invention, the amount of the organic solvent used is such that the concentration of the noble metal element in the organic mixed solution is 0.001-0.1 mol / L, preferably 0.002-0.07 mol / L.

[0043] According to a preferred embodiment of the present invention, the reaction process in step (3) further comprises: cooling the reaction system in step (2) and then introducing an organic solvent and a noble metal salt.

[0044] According to a preferred embodiment of the present invention, the reaction conditions in step (3) include: temperature of 245-300°C; reaction pressure of 10-20 MPa; reaction time of 10-150 min; preferably, temperature of 245-280°C; reaction pressure of 12-18 MPa; reaction time of 30-120 min.

[0045] According to a preferred embodiment of the present invention, the method further comprises washing and drying the sample obtained in step (3) to obtain composite material powder. In the present invention, any conventional method and conditions can be used for washing and drying, which will not be described in detail here.

[0046] According to a preferred embodiment of the present invention, the mixed reaction process of the indium zirconium carbon composite material, the organic solvent and the noble metal salt in step (3) includes: cooling the autoclave to a set temperature, introducing the organic solvent and the noble metal salt solution, and reacting under the supercritical state of the organic solution; finally, releasing the pressure and venting the gas to terminate the reaction, waiting for the reactor to cool to an appropriate temperature, disassembling the reactor, washing the sample, and drying it to obtain a catalyst powder.

[0047] According to a preferred embodiment of the present invention, the heat treatment conditions in step (4) include: under an inert atmosphere, a temperature of 250-500°C, and a time of 1-5h; preferably, a temperature of 350-420°C, and a time of 1.5-3h.

[0048] According to a preferred embodiment of the present invention, the inert atmosphere is a nitrogen atmosphere and / or an argon atmosphere.

[0049] A second aspect of the present invention provides a noble metal-supported indium-zirconium-carbon composite material prepared by the preparation method described in the first aspect. The noble metal-supported indium-zirconium-carbon composite material has a simple preparation process and, when used as a catalyst, exhibits excellent catalytic performance, high reaction activity, high selectivity for the target product, and good reaction stability.

[0050] A third aspect of the present invention provides a method for preparing methanol by hydrogenating carbon dioxide, the method comprising:

[0051] Under the conditions of producing methanol by hydrogenation of carbon dioxide, carbon dioxide and hydrogen are contacted in the presence of a catalyst; the catalyst is the noble metal-loaded indium zirconium-carbon composite material described in the second aspect.

[0052] Preferably, the conditions for the carbon dioxide hydrogenation reaction to produce methanol include: reaction pressure of 0.3MPa-8MPa, reaction temperature of 100℃-500℃, volume space velocity of 1500h -1 -40000h -1, H2 / CO2 molar ratio is 1-7; further preferably, the conditions for the carbon dioxide hydrogenation reaction to prepare methanol include: reaction pressure of 1MPa-5MPa, reaction temperature of 200℃-400℃, volume space velocity of 10000h -1 -20000h -1 , the H2 / CO2 molar ratio is 4 to 6. Preferably, the carbon dioxide hydrogenation reaction is carried out in a fixed bed reactor.

[0053] Adopting the above preferred embodiment is beneficial to improving CO2 conversion rate and methanol selectivity.

[0054] The present invention will be described in detail below through examples.

[0055] In the following examples, the raw materials used were all purchased from commercial sources.

[0056] Example 1

[0057] (1) 15.44 g of In(NO3)3·4H2O and 2.96 g of Zr(NO3)4·5H2O were added to 100 mL of deionized water, and 15 g of sucrose was added, and the mixture was stirred to prepare a mixed solution; the mixed solution was added to an autoclave, and then 4 g of a 30% H2O2 solution and 120 mL of deionized water were added, and then the temperature was raised to 400°C and the pressure was increased to 25 MPa, and the reaction was carried out for 20 minutes; after the reaction was completed, the pressure was released and cooled to achieve gas-solid-liquid separation, and the solid remaining in the autoclave was the indium zirconium carbon composite material;

[0058] (2) After the autoclave in step (1) is cooled to 246°C, 100 mL of methanol and 0.07 g of palladium nitrate are introduced and the reaction is carried out at 12 MPa for 50 min; finally, the pressure is released to terminate the reaction, and the autoclave is cooled to 80°C, the autoclave is disassembled, and the sample is washed and dried to obtain a palladium-loaded indium zirconium-carbon composite material powder; the above powder is placed in a tubular furnace and heated at 350°C in a N2 atmosphere and calcined for 3 h to obtain a palladium-loaded indium zirconium-carbon composite material.

[0059] (3) The reaction of carbon dioxide hydrogenation to methanol was carried out in a stainless steel reactor with an inner diameter of 8 mm. The reaction conditions were as follows: 3.0 MPa, 220 °C, 10,000 h -1 , n(H2) / n(CO2)=4, the liquid product was collected in an ice-water bath, and the product composition was analyzed by gas chromatography. The evaluation results are shown in Table 1.

[0060] Comparative Example 1

[0061] (1) 15.44 g In(NO3)3·4H2O and 2.96 g Zr(NO3)4·5H2O were added to a mixture of 96 mL anhydrous ethanol and 58 mL deionized water. 19 g urea was added to a mixture of 96 mL anhydrous ethanol and 24 mL deionized water. The precipitant solution was added to the metal indium salt solution at 25°C to obtain a mother solution, which was stirred thoroughly for 5 h. The mother solution was then added to a 100 mL polytetrafluoroethylene-lined hydrothermal synthesis reactor and placed in a forced air drying oven for aging at 120°C for 20 h. After the hydrothermal reactor cooled to room temperature, the mother solution was centrifuged with deionized water to a pH of 7, dried at 60°C for 20 h, and calcined at 350°C for 3 h to obtain an indium zirconium oxide catalyst.

[0062] (2) The activity of the prepared indium zirconium oxide catalyst was evaluated in a fixed bed reactor. The reaction conditions were the same as in Example 1. The test results are shown in Table 1.

[0063] Comparative Example 2

[0064] (1) The preparation of indium zirconium oxide catalyst is the same as that of comparative example 1.

[0065] (2) Weigh 0.07 g of palladium nitrate and dissolve it in deionized water to obtain a palladium salt solution. Then weigh 2 g of indium oxide catalyst and put it into the palladium salt solution. Stir at 25° C. for 1 hour, then dry it by rotary evaporation at 45° C., 20 ppm, and 0.1 MPa, and finally calcine it at 350° C. for 4 hours to obtain a Pd-loaded indium zirconium oxide catalyst, which is pressed into tablets and sieved into 40-60 mesh.

[0066] (3) The activity of the prepared palladium-supported indium zirconium oxide catalyst was evaluated in a fixed bed reactor. The reaction conditions were the same as in Example 1. The test results are shown in Table 1.

[0067] Example 2

[0068] (1) 35.6 g of In(NO3)3·4H2O and 4.55 g of Zr(NO3)4·5H2O were added to 100 mL of deionized water, and 36 g of maleic acid was added, and the mixture was stirred to prepare a mixed solution; the mixed solution was added to an autoclave, and 6 g of a 30% H2O2 solution and 120 mL of deionized water were added, and then the temperature was raised to 380°C and the pressure was increased to 24 MPa, and the reaction was carried out for 25 min; after the reaction was completed, the pressure was released and cooled to achieve gas-solid-liquid separation, and the solid remaining in the autoclave was the indium zirconium carbon composite material;

[0069] (2) After the autoclave in step (1) is cooled to 275°C, 100 mL of methanol and 0.20 g of palladium nitrate are introduced and the reaction is carried out at 13 MPa for 40 min; finally, the pressure is released to terminate the reaction, and the autoclave is cooled to 75°C, the autoclave is disassembled, and the sample is washed and dried to obtain a palladium-loaded indium zirconium-carbon composite material powder; the above powder is placed in a tubular furnace and heated at 380°C in a N2 atmosphere and calcined for 2 h to obtain a palladium-loaded indium zirconium-carbon composite material.

[0070] (3) The reaction of carbon dioxide hydrogenation to methanol was carried out in a stainless steel reactor with an inner diameter of 8 mm. The reaction conditions were as follows: 5.0 MPa, 200 °C, 8000 h -1 , n(H2) / n(CO2)=6, the liquid product was collected in an ice-water bath, and the product composition was analyzed by gas chromatography. The evaluation results are shown in Table 1.

[0071] Example 3

[0072] (1) 63.8 g of In(NO3)3·4H2O and 18.37 g of Zr(NO3)4·5H2O were added to 300 mL of deionized water, and 55 g of terephthalic acid was added, and the mixture was stirred to prepare a mixed solution; the mixed solution was added to an autoclave, and then 8 g of a 30% H2O2 solution and 300 mL of deionized water were added, and then the temperature was raised to 520°C and the pressure was increased to 25 MPa, and the reaction was carried out for 140 min; after the reaction was completed, the pressure was released and cooled to achieve gas-solid-liquid separation, and the solid remaining in the autoclave was the indium zirconium carbon composite material;

[0073] (2) After the autoclave in step (1) is cooled to 259°C, 120 mL of ethanol and 0.36 g of palladium nitrate are introduced and the reaction is carried out at 18 MPa for 35 minutes; finally, the pressure is released to terminate the reaction, and the autoclave is cooled to 75°C, the autoclave is disassembled, and the sample is washed and dried to obtain a palladium-loaded indium zirconium-carbon composite material powder; the above powder is placed in a tubular furnace and heated at 400°C in a N2 atmosphere and calcined for 2 hours to obtain a palladium-loaded indium zirconium-carbon composite material.

[0074] (3) The reaction of carbon dioxide hydrogenation to methanol was carried out in a stainless steel reactor with an inner diameter of 8 mm. The reaction conditions were as follows: 5.0 MPa, 340 °C, 15000 h -1 , n(H2) / n(CO2)=4, the liquid product was collected in an ice-water bath, and the product composition was analyzed by gas chromatography. The evaluation results are shown in Table 1.

[0075] Example 4

[0076] (1) 26.8 g of In(NO3)3·4H2O and 13.23 g of Zr(NO3)4·5H2O were added to 100 mL of deionized water, and 22 g of pyridinedicarboxylic acid was added, and the mixture was stirred to prepare a mixed solution; the mixed solution was added to an autoclave, and 3 g of a 30% H2O2 solution and 120 mL of deionized water were added, and then the temperature was raised to 450°C and the pressure was increased to 35 MPa, and the reaction was carried out for 80 min; after the reaction was completed, the pressure was released and cooled to achieve gas-solid-liquid separation, and the solid remaining in the autoclave was the indium zirconium carbon composite material;

[0077] (2) After the autoclave in step (1) is cooled to 260°C, 100 mL of ethanol and 0.30 g of palladium nitrate are introduced and the reaction is carried out at 17 MPa for 80 min; finally, the pressure is released to terminate the reaction, and the autoclave is cooled to 75°C, the autoclave is disassembled, and the sample is washed and dried to obtain a palladium-loaded indium zirconium-carbon composite material powder; the above powder is placed in a tubular furnace and heated at 420°C in a N2 atmosphere and calcined for 1.5 h to obtain a palladium-loaded indium zirconium-carbon composite material.

[0078] (3) The reaction of carbon dioxide hydrogenation to methanol was carried out in a stainless steel reactor with an inner diameter of 8 mm. The reaction conditions were as follows: 1.0 MPa, 400 °C, 10,000 h -1 , n(H2) / n(CO2)=5, the liquid product was collected in an ice-water bath, and the product composition was analyzed by gas chromatography. The evaluation results are shown in Table 1.

[0079] Example 5

[0080] (1) 102.3 g of In(NO3)3·4H2O and 78.53 g of Zr(NO3)4·5H2O were added to 400 mL of deionized water, and 100 g of tartaric acid was added, and the mixture was stirred to prepare a mixed solution; the mixed solution was added to an autoclave, and then 10 g of a 30% H2O2 solution and 420 mL of deionized water were added, and then the temperature was raised to 480°C and the pressure was increased to 30 MPa, and the reaction was carried out for 140 min; after the reaction was completed, the pressure was released and cooled to achieve gas-solid-liquid separation, and the solid remaining in the autoclave was the indium zirconium carbon composite material;

[0081] (2) After the autoclave in step (1) is cooled to 255°C, 100 mL of methanol and 1.65 g of palladium nitrate are introduced and the reaction is carried out at 15 MPa for 60 min; finally, the pressure is released to terminate the reaction, and the autoclave is cooled to 75°C, the autoclave is disassembled, and the sample is washed and dried to obtain a palladium-loaded indium zirconium-carbon composite material powder; the above powder is placed in a tubular furnace and heated at 360°C in a N2 atmosphere and calcined for 3 h to obtain a palladium-loaded indium zirconium-carbon composite material.

[0082] (3) The reaction of carbon dioxide hydrogenation to methanol was carried out in a stainless steel reactor with an inner diameter of 8 mm. The reaction conditions were as follows: 4.0 MPa, 250°C, 20,000 h -1 , n(H2) / n(CO2)=6, the liquid product was collected in an ice-water bath, and the product composition was analyzed by gas chromatography. The evaluation results are shown in Table 1.

[0083] Table 1

[0084]

[0085] It can be seen from the results in Table 1 that the noble metal-loaded indium zirconium carbon composite material prepared by the present invention has the advantages of excellent catalytic performance, high reaction activity, high selectivity of target products, good reaction stability, and low deactivation rate in the reaction of preparing methanol by hydrogenation of carbon dioxide.

[0086] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a noble metal-loaded indium-zirconium-carbon composite material, characterized in that: The following steps are involved: (1) providing a mixed solution containing an In salt, a Zr salt, a carbon source, and water; wherein the mass ratio of the total amount of the In salt and the Zr salt in the mixed solution to the carbon source is 1-2:1; (2) reacting the mixed solution in a supercritical state of water to obtain an indium zirconium carbon composite material; the reaction conditions include: a temperature of 400-600° C.; a reaction pressure of 23-45 MPa; (3) mixing the indium zirconium carbon composite material, an organic solvent and a noble metal salt to obtain an organic mixed solution, and then reacting the organic solvent under a supercritical state; (4) heat-treating the product obtained by the reaction in step (3); Based on the total amount of metals, the molar composition of the In salt and the Zr salt is: In: 40-95%, Zr: 5-60%.

2. The preparation method according to claim 1, wherein Based on the total amount of metals, the molar composition of the In salt and the Zr salt is: In: 60-90%, Zr: 10-40%.

3. The preparation method according to claim 1, wherein In the mixed solution, the total concentration of In salt and Zr salt is 0.1-4 mol / L.

4. The preparation method according to claim 1, wherein The In salt and the Zr salt are each independently selected from soluble salts of metals, and the soluble salts are inorganic salts and / or organic substances.

5. The preparation method according to claim 4, wherein The soluble salt is selected from at least one of nitrates, sulfates, acetates, chlorides, and metal alkoxides.

6. The preparation method according to claim 1, wherein The mass ratio of the total amount of In salt and Zr salt to the carbon source in the mixed solution is 1.1-1.9:

1.

7. The preparation method according to claim 1, wherein The carbon source is selected from at least one of sucrose, starch, glucose, maltose, cellulose, citric acid, maleic acid, fumaric acid, succinic acid, tartaric acid, malic acid, gluconic acid, terephthalic acid, ethylenediaminetetraacetic acid, pyridinedicarboxylic acid and trimesic acid.

8. The preparation method according to claim 7, wherein The carbon source is selected from at least one of sucrose, maleic acid, terephthalic acid, pyridinedicarboxylic acid and tartaric acid.

9. The preparation method according to claim 1, wherein The mixed solution also contains an oxidant.

10. The preparation method according to claim 9, wherein The oxidant is H2O2.

11. The preparation method according to claim 9, wherein The oxidizing agent is provided in the form of a solution.

12. The preparation method according to claim 9, wherein Based on the total mass of the mixed solution, the amount of the oxidant is 0.1-1 mass %.

13. The preparation method according to claim 1, wherein The reaction conditions of step (2) include: reaction time is 1-200 min.

14. The preparation method according to claim 1, wherein The reaction conditions of step (2) include: temperature of 400-520° C.; reaction pressure of 25-35 MPa; and reaction time of 20-150 min.

15. The preparation method according to claim 1, wherein The noble metal in the noble metal salt is selected from at least one of platinum, palladium, ruthenium and rhodium.

16. The preparation method according to claim 15, wherein The noble metal salt is palladium.

17. The preparation method according to claim 1, wherein The noble metal salt is selected from at least one of palladium nitrate, palladium dichloride, palladium sulfate, potassium tetrachloropalladate, sodium tetrachloropalladate, potassium hexachloropalladate and sodium hexachloropalladate.

18. The preparation method according to claim 1, wherein The amount of the noble metal salt used is such that, in the obtained noble metal-loaded indium-zirconium-carbon composite material, the molar ratio of In to the noble metal element is 1:0.001-0.3, calculated on an element basis.

19. The preparation method according to claim 1, wherein The organic solvent is selected from alcohols.

20. The preparation method according to claim 19, wherein The organic solvent is methanol and / or ethanol.

21. The preparation method according to claim 1, wherein The amount of the organic solvent used is such that the concentration of the noble metal element in the organic mixed solution is 0.001-0.1 mol / L.

22. The preparation method according to claim 1, wherein The reaction conditions of step (3) include: temperature of 245-300° C.; reaction pressure of 10-20 MPa; and reaction time of 10-150 min.

23. The preparation method according to claim 22, wherein The temperature is 245-280°C; the reaction pressure is 12-18 MPa; and the reaction time is 30-120 min.

24. The preparation method according to claim 1, wherein The heat treatment conditions in step (4) include: in an inert atmosphere, a temperature of 250-500° C., and a time of 1-5 hours.

25. The preparation method according to claim 24, wherein The temperature is 350-420℃ and the time is 1.5-3h.

26. A noble metal-loaded indium-zirconium-carbon composite material prepared by the preparation method according to any one of claims 1 to 25.

27. A method for preparing methanol by hydrogenating carbon dioxide, the method comprising: Under conditions of producing methanol by hydrogenation of carbon dioxide, carbon dioxide and hydrogen are contacted in the presence of a catalyst; The catalyst is the noble metal-loaded indium-zirconium-carbon composite material according to claim 26.

28. The method according to claim 27, wherein The conditions for the carbon dioxide hydrogenation reaction to produce methanol include: reaction pressure of 0.3MPa-8MPa, reaction temperature of 100℃-500℃, volume space velocity of 1500h -1 -40000h -1 , the H2 / CO2 molar ratio is 1-7.

Images