Copper-zinc-zirconium catalyst and its preparation method and application

Abstract

The present invention relates to the field of catalysts and discloses a copper-zinc-zirconium catalyst and its preparation method and application. The method comprises: (1) mixing a Cu source, a Zn source and a Zr source with a carbon-containing compound in the presence of a solvent to obtain a mixed solution; (2) reacting the mixed solution with supercritical water, and then heat-treating the product obtained by the reaction; based on the total amount of metal, the molar composition of the Cu source, the Zn source and the Zr source is as follows: Cu: 30-90%, Zn: 5-40%, Zr: 5-40%. The present invention adopts a simple and efficient supercritical fluid deposition technology to obtain C-CuZnZrO with adjustable particle size and morphology. x The preparation process is simple and low-cost, and the catalyst regeneration process is simple. The CO2 conversion rate in the fixed bed reactor is high, the methanol yield is high, and it has excellent catalytic performance.

Description

Technical Field

[0001] The present invention relates to the field of catalysts, and in particular to a copper-zinc-zirconium catalyst and a preparation method and application thereof. Background Art

[0002] The production of methanol through the reaction of CO2 with hydrogen from renewable energy sources not only addresses greenhouse gas emissions but also represents an effective approach to fossil fuel substitution. In recent years, CO2 hydrogenation to methanol has garnered widespread attention. Nobel laureate Euler even elevated this process to the level of a "methanol economy." This is because, among the many CO2 resource utilization processes, CO2 hydrogenation to methanol is relatively simple and can be modeled on the established industrial process of syngas-to-methanol, significantly reducing the risk of industrial scale-up. Furthermore, the production of methanol as a product preserves one of the oxygen atoms in the CO2, reducing hydrogen resource consumption and making the process more economical. The resulting methanol, in addition to being a clean energy source, can also be used through catalytic processes to produce downstream products such as methanol, aromatics, and gasoline, making it an ideal high-value-added chemical alternative to traditional resources like oil and natural gas. Therefore, utilizing CO2 hydrogenation to produce methanol is an effective means of addressing current CO2 emissions and the depletion of fossil energy resources.

[0003] Although the CO2 hydrogenation reaction to produce methanol is thermodynamically feasible, the chemical stability of the CO2 molecule causes the reaction process to overcome a large energy barrier. Therefore, the role of the catalyst is very important in this reaction process. In the prior art, the catalyst used for the CO2 hydrogenation reaction to produce methanol is mainly copper-zinc-based catalysts. However, the performance of industrial methanol synthesis catalysts directly used for CO2 hydrogenation to produce methanol is very poor. This is because the methanol synthesis of the synthesis gas route is different from the reaction of CO2 hydrogenation to produce methanol. In addition to producing methanol, the latter also produces an equal amount of water. Therefore, it is necessary to optimize the preparation of copper-zinc-based catalysts. CN102580750A uses a co-current co-precipitation method to prepare a catalyst for the hydrogenation of carbon dioxide to produce methanol. The catalyst is mainly composed of a composite oxide of Cu, Zn, Al and Ti. The catalyst has high activity and stability at relatively low temperatures and low pressures. CN103252241A uses a citric acid complex combustion method to prepare a catalyst containing Cu, Zn and La oxides, which has the advantages of high conversion rate and selectivity. The catalyst in CN103263926A is prepared by a co-precipitation method using a mixed solution of NaOH and Na2CO3 as a precipitant, and has the advantages of high carbon dioxide conversion rate, good methanol selectivity, and high methanol yield.

[0004] It can be seen that there are two ways to modify copper-zinc-based catalysts in the prior art. One is to introduce an auxiliary agent; the other is to break through the co-precipitation method and adopt a new preparation method. These methods can achieve the purpose of improving the catalytic performance of copper-zinc-based catalysts in the CO2 hydrogenation to methanol reaction, but there are still certain shortcomings. The introduction of auxiliary components increases the composition of the catalyst, and the repeatability of the catalyst preparation is difficult to guarantee. There are many factors that need to be examined and adjusted when improving the performance. For example, the preparation conditions of the citric acid complex combustion method are difficult to control, and the prepared catalyst is not easy to shape. In addition, in order to ensure the effect, citric acid is usually excessive, which will produce a large amount of CO2 gas during the combustion process.

[0005] Therefore, there is an urgent need to develop a CO2 hydrogenation catalyst with simple preparation process, high stability, high catalytic activity, good reaction stability and low deactivation rate. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems of the existing technology of CO2 hydrogenation catalyst, such as complex preparation process, poor reproducibility, low catalyst activity and poor reaction stability, and to provide a copper-zinc-zirconium catalyst and its preparation method and application. The preparation method is simple in process and high in stability. The copper-zinc-zirconium catalyst prepared has high catalytic activity, good reaction stability and low deactivation rate.

[0007] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a copper-zinc-zirconium catalyst, the method comprising:

[0008] (1) In the presence of a solvent, a Cu source, a Zn source, and a Zr source are mixed with a carbon-containing compound to obtain a mixed solution;

[0009] (2) reacting the mixed solution with supercritical water, and then heat-treating the reaction product;

[0010] Based on the total amount of metal, the molar composition of the Cu source, the Zn source and the Zr source is as follows: Cu: 30-90%, Zn: 5-40%, Zr: 5-40%.

[0011] The second aspect of the present invention provides a copper-zinc-zirconium catalyst prepared by the preparation method described in the first aspect.

[0012] The third aspect of the present invention provides the use of the copper-zinc-zirconium catalyst described in the second aspect in the reaction of producing methanol by hydrogenation of carbon dioxide.

[0013] Preferably, the conditions for the carbon dioxide hydrogenation reaction to produce methanol include: reaction pressure of 0.5MPa-8MPa, reaction temperature of 150℃-450℃, volume space velocity of 5000h -1 -30000h -1, the H2 / CO2 molar ratio is 1-10.

[0014] Through the above technical solution, the beneficial effects obtained by the present invention are as follows:

[0015] (1) The present invention adopts a simple and efficient supercritical fluid deposition technology. By adjusting the temperature and pressure, the Cu, Zn and Zr precursors are instantly supersaturated in the supercritical solution, forming a large number of crystal nuclei, and further growing C-CuZnZrO with adjustable particle size and morphology for the reaction. x .

[0016] (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.

[0017] (3) The copper-zinc-zirconium catalyst of the present invention has low cost, a simple catalyst regeneration process, and a high CO2 conversion rate in a fixed-bed reactor. It is a non-precious metal catalyst with market competitiveness. DETAILED DESCRIPTION

[0018] 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.

[0019] The first aspect of the present invention provides a method for preparing a copper-zinc-zirconium catalyst, the method comprising:

[0020] (1) In the presence of a solvent, a Cu source, a Zn source, and a Zr source are mixed with a carbon-containing compound to obtain a mixed solution;

[0021] (2) reacting the mixed solution with supercritical water, and then heat-treating the reaction product;

[0022] Based on the total amount of metal, the molar composition of the Cu source, the Zn source and the Zr source is as follows: Cu: 30-90%, Zn: 5-40%, Zr: 5-40%.

[0023] According to the present invention, supercritical water has strong reactivity and wide solubility, which is beneficial to fast mass transfer and increased reaction rate. In a supercritical water environment, the solubility of metal oxides is low, so the nucleation rate is high, which is beneficial to the synthesis of nanoparticles. By adjusting the temperature and pressure, the Cu, Zn and Zr precursors are instantly supersaturated in the supercritical solution, forming a large number of crystal nuclei, and further growing C-CuZnZrO with adjustable particle size and morphology for the reaction.x .

[0024] According to the present invention, the C-CuZnZrO prepared by combining Cu, Zn and Zr x The catalyst is beneficial to improving the CO2 conversion rate and methanol selectivity.

[0025] According to a preferred embodiment of the present invention, the molar composition of the Cu source, Zn source, and Zr source, calculated as elements, based on the total amount of metals, is: Cu: 30-80%, Zn: 10-30%, and Zr: 10-30%. The copper-zinc-zirconium catalyst prepared under these preferred conditions has higher reactivity.

[0026] According to a preferred embodiment of the present invention, in the mixed solution, the total concentration of the Cu source, the Zn source and the Zr source is 0.1-3 mol / L, further preferably 0.5-2 mol / L, and more preferably 0.7-1.5 mol / L. The adoption of the above preferred embodiment is beneficial to improving the CO2 conversion rate and methanol selectivity.

[0027] In the present invention, there is no specific limitation on the sources of the Cu source, Zn source and Zr source. Preferably, they can be independently selected from soluble salts of metals; more preferably, the soluble salts are selected from inorganic salts and / or organic matter.

[0028] According to a preferred embodiment of the present invention, the inorganic salt is selected from at least one of sulfate, chloride, acetate, and nitrate; for example, the Cu source, Zn source, and Zr source can be copper nitrate, zinc nitrate, and zirconium nitrate, respectively; and the organic matter can be a metal alkoxide.

[0029] According to a preferred embodiment of the present invention, the mass ratio of the total amount of the Cu source, Zn source, and Zr source to the carbon-containing compound is 1-2:1, preferably 1.1-1.6:1. Controlling the mass ratio of the total amount of the Cu source, Zn source, and Zr source to the carbon-containing compound within the above preferred range is beneficial for enhancing the active sites of the catalyst.

[0030] In the present invention, the carbon-containing compound has a wide range of choices, as long as it can provide the required carbon source. Preferably, the carbon-containing compound is selected from at least one of maltose, sucrose, starch, glucose, cellulose, citric acid, maleic acid, fumaric acid, malic acid, succinic acid, tartaric acid, gluconic acid, terephthalic acid, ethylenediaminetetraacetic acid, dipicolinic acid and trimesic acid, and more preferably at least one of sucrose, citric acid, phthalic acid, ethylenediaminetetraacetic acid and gluconic acid.

[0031] According to the present invention, there are no specific limitations on the mixing method and conditions for the mixed solution in step (1). Conventional methods can be used for mixing, as long as the components are uniformly mixed. Preferably, the mixing process of the Cu source, Zn source, and Zr source with the carbon-containing compound also includes a heating process. Specifically, the heating temperature can be 40-60°C.

[0032] According to a preferred embodiment of the present invention, the mixed liquid further contains a solvent. The type of the solvent is not specifically limited, as long as it can achieve dissolution and dispersion of the Cu source, Zn source, Zr source and the carbon-containing compound. Preferably, the solvent is water.

[0033] According to a preferred embodiment of the present invention, in step (2), the mass of the supercritical water is greater than the mass of the mixed solution. Further preferably, the mass ratio of the mixed solution to the supercritical water is 1:1.1-2.5, preferably 1:1.2-2.2. Adopting the above preferred conditions helps the Cu, Zn, and Zr precursors in the mixed solution quickly reach a supersaturated state, further facilitating the formation of crystal nuclei.

[0034] According to a preferred embodiment of the present invention, the reaction in step (2) is a supercritical reaction, which is carried out rapidly under high temperature and high pressure conditions. Preferably, the reaction conditions include: reaction temperature of 400-650°C, reaction pressure of 23-40MPa; reaction time of 40-250s; preferably, the reaction conditions in step (2) include: reaction temperature of 400-500°C, reaction pressure of 23-35MPa; reaction time of 60-200s.

[0035] In the present invention, there is no particular limitation on the specific manner of the mixing reaction of the mixed solution and supercritical water in step (2), as long as the above-mentioned reaction can be achieved.

[0036] According to a preferred embodiment of the present invention, the mixing of the mixed solution and supercritical water in step (2) for reaction comprises:

[0037] The mixed liquid and heated water are respectively fed into reactors for reaction.

[0038] In the present invention, the mixing reaction of the mixed solution and supercritical water in step (2) can be carried out in any conventional reactor as long as it can achieve the above-mentioned reaction. Preferably, the reactor is a tubular split-flow reactor. When a tubular split-flow reactor is used, the flow rates of the mixed solution and water can be further controlled, which helps to control the reaction rate and the amount of material input.

[0039] According to a preferred embodiment of the present invention, the step of mixing and reacting supercritical water and a mixed liquid comprises: using a pump to pump the mixed liquid into a reactor; another pump to pump water into the reactor, passing through a heater in the middle to heat the water to a supercritical state.

[0040] Preferably, the flow rate of the mixed liquid is 7-22 ml / min, more preferably 10-18 ml / min; the flow rate of the heated water is 15-35 ml / min, more preferably 16-28 ml / min.

[0041] According to a preferred embodiment of the present invention, water is heated before being fed into the reactor, preferably, the water is heated to 400-650° C. Preferably, the heating device is a three-stage furnace, and the internal pressure can be 23-40 MPa.

[0042] According to a preferred embodiment of the present invention, the method further comprises introducing an oxidant into the mixed solution; specifically, the oxidant may be introduced into the Cu source, Zn source and Zr source, and then the carbon-containing compound is added, or the oxidant may be introduced after the mixed solution is obtained; preferably, the oxidant is introduced after the mixed solution is obtained.

[0043] According to a preferred embodiment of the present invention, the oxidant is H2O2, and preferably the oxidant is provided in the form of a solution. By introducing the oxidant, the oxidizing property of supercritical water can be improved.

[0044] 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 0.3-0.8% by mass.

[0045] According to the present invention, the heat treatment can be carried out using conventional heat treatment methods and conditions. Preferably, the heat treatment conditions include: in an inert atmosphere, a temperature of 280-550°C, and a time of 1-4 hours; preferably, a temperature of 350-420°C, and a time of 1.5-3 hours.

[0046] According to a preferred embodiment of the present invention, the inert atmosphere is a nitrogen atmosphere and / or an argon atmosphere.

[0047] According to a preferred embodiment of the present invention, the method further comprises cooling and / or filtering the reaction product obtained in step (2). Specifically, the fluid after the reaction is passed through a cooling system and a filtering system.

[0048] According to a preferred embodiment of the present invention, the method further comprises washing and drying the cooled sample to obtain catalyst powder. In the present invention, the washing and drying method is not specifically limited and can be performed using any conventional method and conditions.

[0049] The second aspect of the present invention provides a copper-zinc-zirconium catalyst prepared by the preparation method described in the first aspect. The copper-zinc-zirconium catalyst has low preparation cost, simple catalyst regeneration process, and high CO2 conversion rate and methanol selectivity.

[0050] The third aspect of the present invention provides the use of the copper-zinc-zirconium catalyst described in the second aspect in the reaction of hydrogenating carbon dioxide to produce methanol. Preferably, the conditions for the reaction of hydrogenating carbon dioxide to produce methanol include: a reaction pressure of 0.5 MPa-8 MPa, a reaction temperature of 150°C-450°C, a volume space velocity of 5000 h-1, and a reaction temperature of 150°C-450°C. -1 -30000h -1 , H2 / CO2 molar ratio is 1-10; preferably the reaction pressure is 1MPa-5MPa, the reaction temperature is 200℃-400℃, and the volume space velocity is 8000h -1 -20000h -1 , the H2 / CO2 molar ratio is 4 to 6. Under the above preferred embodiment, it is beneficial to improve the CO2 conversion rate and methanol selectivity.

[0051] According to a preferred embodiment of the present application, the carbon dioxide hydrogenation reaction is carried out in a fixed bed reactor.

[0052] The present invention will be described in detail below through examples.

[0053] In the following examples, the raw materials used were all purchased from commercial sources.

[0054] Example 1

[0055] (1) 27.2 g of Cu(NO3)2·3H2O, 4.2 g of Zn(NO3)2·6H2O, and 6.0 g of Zr(NO3)4·5H2O were added to 100 mL of deionized water, and 30 g of sucrose was added. The mixture was stirred at 50°C for 1 h, and then 4 g of 30% H2O2 solution was added and stirred for 30 min. The mixed solution was pumped into the reactor with a flow rate of 9 ml / min. At the same time, another pump heated the deionized water to 450°C through a heater, so that the deionized water was heated to a supercritical state, and then pumped into the reactor with a flow rate of 16 ml / min. The reactor was a tubular split-flow reactor with a temperature of 450°C and a pressure of 30 MPa. The reaction was carried out for 60 s. After the reaction, the sample was cooled and filtered. The cooled sample was washed and dried to obtain a catalyst powder. The catalyst powder was placed in a tubular furnace and calcined at 350°C in a N2 atmosphere for 3 h to obtain a copper-zinc-zirconium catalyst.

[0056] (2) 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.

[0057] Comparative Example 1

[0058] (1) Add 27.2 g of Cu(NO3)2•3H2O, 4.2 g of Zn(NO3)2•6H2O, and 6.0 g of Zr(NO3)4•5H2O to 100 mL of deionized water and stir to dissolve. Weigh 100 g of sodium carbonate and add it to 300 mL of deionized water and stir to dissolve. Titrate the salt solution and sodium carbonate solution in parallel, controlling the pH to be around 9.0. Continue stirring for 1 h after the titration. After standing overnight, pour off the supernatant and centrifuge. Wash four times with 60°C deionized water. After centrifugation, dry the solid at 60°C for 15 h and 120°C for 2 h.

[0059] (2) The activity of the prepared copper-zinc-zirconium catalyst was evaluated in a fixed-bed reactor. The reaction conditions were the same as those in Example 1. The test results are shown in Table 1.

[0060] Example 2

[0061] (1) 30.0 g of Cu(NO3)2•3H2O, 10.55 g of Zn(NO3)2•6H2O, and 7.62 g of Zr(NO3)4•5H2O were added to 100 mL of deionized water. 35 g of citric acid was added and the mixture was stirred at 50°C for 1 h. Then, 5 g of 30% H2O2 solution was added and the mixture was stirred for 30 min. The mixed solution was pumped into the reactor at a flow rate of 13 ml / min. At the same time, another pump heated the deionized water to 400°C through a heater, causing the deionized water to reach a supercritical state. The mixture was then pumped into the reactor at a flow rate of 25 ml / min. The reactor was a tubular split-flow reactor with a temperature of 400°C and a pressure of 25 MPa. The reaction was carried out for 100 s. After the reaction, the mixture was cooled and filtered. The cooled sample was washed and dried to obtain a catalyst powder. The catalyst powder was placed in a tubular furnace and calcined at 380°C in a N2 atmosphere for 2 h to obtain a copper-zinc-zirconium catalyst.

[0062] (2) 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.

[0063] Example 3

[0064] (1) 42.0 g of Cu(NO3)2•3H2O, 17.24 g of Zn(NO3)2•6H2O, and 24.88 g of Zr(NO3)4•5H2O were added to 300 mL of deionized water. 65 g of gluconic acid was added and stirred at 50°C for 1 h. Then, 10 g of a 30% H2O2 solution was added and stirred for 30 min. The mixed solution was pumped into the reactor at a flow rate of 17 ml / min. At the same time, another pump heated the deionized water to 500°C through a heater, causing the deionized water to reach a supercritical state. The deionized water was then pumped into the reactor at a flow rate of 28 ml / min. The reactor was a tubular split-flow reactor with a temperature of 500°C and a pressure of 24 MPa. The reaction was carried out for 200 s. After the reaction, the sample was cooled and filtered. The cooled sample was washed and dried to obtain a catalyst powder. The catalyst powder was placed in a tubular furnace and calcined at 400°C in a N2 atmosphere for 2 h to obtain a copper-zinc-zirconium catalyst.

[0065] (2) 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.

[0066] Example 4

[0067] (1) 12.4 g of Cu(NO3)2•3H2O, 9.2 g of Zn(NO3)2•6H2O, and 8.8 g of Zr(NO3)4•5H2O were added to 100 mL of deionized water, and 20 g of terephthalic acid was added. The mixture was stirred at 50°C for 1 h, and then 2 g of 30% H2O2 solution was added and stirred for 30 min. The mixed solution was pumped into the reactor with a flow rate of 10 ml / min. At the same time, another pump passed the deionized water through a heater and heated it to 450°C, so that the deionized water was heated to a supercritical state, and then pumped into the reactor with a flow rate of 20 ml / min. The reactor was a tubular split-flow reactor with a temperature of 450°C and a pressure of 30 MPa. The reaction was carried out for 60 s. After the reaction, the sample was cooled and filtered. The cooled sample was washed and dried to obtain a catalyst powder. The catalyst powder was placed in a tubular furnace and calcined at 420°C in a N2 atmosphere for 1.5 h to obtain a copper-zinc-zirconium catalyst.

[0068] (2) 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.

[0069] Example 5

[0070] (1) Add 35.6 g of Cu(NO3)2•3H2O, 32.8 g of Zn(NO3)2•6H2O and 47.4 g of Zr(NO3)4•5H2O to 300 mL of deionized water, add 100 g of ethylenediaminetetraacetic acid, stir at 50 °C for 1 h, then add 6 g of 30% H2O2 solution and continue stirring for 30 min. The mixed solution was pumped into the reactor at a flow rate of 12 ml / min. At the same time, another pump passed deionized water through a heater, heated it to 460°C, heated the deionized water to a supercritical state, and then pumped it into the reactor at a flow rate of 26 ml / min. The reactor was a tubular split-flow reactor with a temperature of 460°C and a pressure of 35 MPa, and the reaction was carried out for 120 seconds. After the reaction was completed, the mixture was cooled and filtered, and the cooled sample was washed and dried to obtain catalyst powder. The catalyst powder was placed in a tubular furnace and heated at 360°C in a N2 atmosphere and calcined for 3 hours to obtain a copper-zinc-zirconium catalyst.

[0071] (2) 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.

[0072] Example 6

[0073] The method of Example 1 was followed, except that no H2O2 solution was added.

[0074] Table 1

[0075]

[0076] It can be seen from the results in Table 1 that the copper-zinc-zirconium catalyst obtained by the preparation method provided in the present invention has excellent catalytic performance, high reaction activity, high CO2 conversion rate and high methanol yield.

[0077] 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 copper-zinc-zirconium catalyst for producing methanol by hydrogenation of carbon dioxide, the method comprising: (1) In the presence of a solvent, a Cu source, a Zn source, and a Zr source are mixed with a carbon-containing compound to obtain a mixed solution; the mass ratio of the total amount of the Cu source, the Zn source, and the Zr source to the carbon-containing compound is 1-2:1; (2) reacting the mixed solution with supercritical water, and then heat-treating the reaction product; Based on the total amount of metal, the molar composition of the Cu source, the Zn source and the Zr source is as follows: Cu: 30-90%, Zn: 5-40%, Zr: 5-40%.

2. The preparation method according to claim 1, wherein Based on the total amount of metal, the molar composition of the Cu source, the Zn source and the Zr source in terms of elements is: Cu: 30-80%, Zn: 10-30%, Zr: 10-30%.

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

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

5. The preparation method according to claim 1, wherein The mass ratio of the total amount of the Cu source, the Zn source and the Zr source to the carbon-containing compound is 1.1-1.6:

1.

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

7. The preparation method according to claim 6, wherein The carbon-containing compound is selected from at least one of sucrose, citric acid, phthalic acid, ethylenediaminetetraacetic acid and gluconic acid.

8. The preparation method according to claim 1, wherein In step (2), the mass ratio of the mixed liquid to supercritical water is 1:1.1-2.

5.

9. The preparation method according to claim 8, wherein In step (2), the mass ratio of the mixed liquid to supercritical water is 1:1.2-2.

2.

10. The preparation method according to claim 1, wherein The reaction conditions of step (2) include: reaction temperature of 400-650° C., reaction pressure of 23-40 MPa; and reaction time of 40-250 s.

11. The preparation method according to claim 10, wherein The reaction conditions of step (2) include: reaction temperature of 400-500°C, reaction pressure of 23-35 MPa; reaction time of 60-200 s.

12. The preparation method according to claim 1, wherein Step (2) mixing the mixed solution with supercritical water to react comprises: The mixed liquid and water heated to a supercritical state are respectively fed into reactors for reaction.

13. The preparation method according to claim 12, wherein The reactor is a tubular split flow reactor.

14. The preparation method according to claim 12, wherein The flow rate of the mixed liquid is 7-22 ml / min, and the flow rate of the water heated to a supercritical state is 15-35 ml / min.

15. The preparation method according to claim 12, wherein The water is heated to 400-650°C and then fed into the reactor.

16. The preparation method according to claim 1, wherein The method further includes introducing an oxidant into the mixed liquor.

17. The preparation method according to claim 16, wherein The oxidant is H2O2.

18. The preparation method according to claim 16, wherein The oxidizing agent is provided in the form of a solution.

19. The preparation method according to claim 16, wherein Based on the total mass of the mixed solution, the amount of the oxidant is 0.1-1% by mass.

20. The preparation method according to claim 1, wherein The heat treatment conditions include: in an inert atmosphere, a temperature of 280-550° C., and a time of 1-4 hours.

21. The preparation method according to claim 20, wherein The heat treatment conditions include: temperature of 350-420° C. and time of 1.5-3 hours.

22. The copper-zinc-zirconium catalyst prepared by the preparation method according to any one of claims 1 to 21.

23. Use of the copper-zinc-zirconium catalyst according to claim 22 in the reaction of producing methanol by hydrogenation of carbon dioxide.

24. The use according to claim 23, wherein: The conditions for the carbon dioxide hydrogenation reaction to produce methanol include: reaction pressure of 0.5MPa-8MPa, reaction temperature of 150℃-450℃, volume space velocity of 5000h -1 -30000h -1 , the H2 / CO2 molar ratio is 1-10.

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