A non-noble metal oxide supported copper-based catalyst and its preparation method and application

Abstract

The present invention discloses a non-precious metal oxide-supported copper-based catalyst, its preparation method, and its application, belonging to the field of catalyst technology. The present invention combines top-down methods such as acid etching and bottom-up deposition-precipitation to construct catalytically active sites with both oxide-metal and metal-oxide structures, which helps improve catalyst durability and reaction selectivity. The resulting catalyst uses micron-sized copper particles as a carrier, with oxide nanoparticles loaded on its surface as a co-catalyst. It exhibits good catalytic activity, high CO2 conversion when used to catalyze CO2 reduction reactions, and excellent stability at high temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a non-noble metal oxide-supported copper-based catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Copper-based catalysts hold broad application prospects in a range of important chemical reactions, including carbon dioxide hydrogenation, synthesis gas conversion, hydrocarbon selective oxidation, methanol steam reforming, and water-gas shift reactions. Scientific research and industrial practice have demonstrated that copper-metal oxide interfaces exhibit excellent activity in these catalytic reactions. Developing catalyst preparation methods with large copper-metal oxide interfaces that are low-cost, highly operable, and easily industrializable has significant economic and strategic implications.

[0003] Carbon dioxide is a common greenhouse gas. Since the Industrial Revolution, atmospheric CO2 concentrations have risen dramatically, from 278 ppm before the Industrial Revolution to 415 ppm by 2021—a nearly 48% increase in just 270 years. This has contributed to a range of issues, including rising global temperatures, melting glaciers, and rising sea levels. Currently, there is a growing consensus on gradually reducing fossil fuel use and seeking renewable alternative energy sources.

[0004] Methanol is an important chemical intermediate and an excellent hydrogen energy carrier. Using "green hydrogen" to convert carbon dioxide into liquid methanol not only reduces CO2 but also enriches energy access, providing more possibilities for alleviating the energy crisis and possessing significant strategic significance. However, CO2's thermodynamic stability and kinetic inertness make its activation very difficult. Therefore, the development of catalysts that promote CO2 activation and hydrogenation reactions is crucial for its resource utilization.

[0005] Copper-based catalysts have excellent activity in activating carbon dioxide, but they suffer from disadvantages such as poor thermal stability and susceptibility to carbon deposition. The development of new thermally stable and carbon-resistant copper-based catalytic systems has far-reaching application potential. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, in a first aspect of the present invention, a method for preparing a copper-based catalyst with a simple process is provided, comprising the following steps:

[0007] (1) mixing powdered copper with a dispersant and a solvent, adding a co-catalyst precursor that can be hydrolyzed to form a metal hydroxide colloid or precipitate to the resulting mixture, and continuing mixing to obtain a copper dispersion;

[0008] (2) adding a nitric acid aqueous solution to the copper dispersion and performing an etching reaction, and removing the solvent after the etching reaction to obtain a reaction product;

[0009] (3) The reaction product is subjected to thermal decomposition treatment to obtain a copper-based catalyst.

[0010] Preferably, in step (1), the copper has a particle size of 0.01 to 5 μm.

[0011] Preferably, in step (1), the dispersant is an organic base, including at least one of oleylamine, ethylenediamine, and isopropanolamine;

[0012] Depending on the type of raw materials of the present invention, a corresponding appropriate solvent can be reasonably used. On the basis of achieving the purpose of the present invention, the choice is diverse. Preferably, in step (1), the solvent includes at least one of water, oleylamine, oleic acid, ethylenediamine, tetrahydrofuran, ethanol, and methanol.

[0013] Preferably, in step (1), the mass ratio of the dispersant to copper is 0.1-10:100, and the mass ratio of the copper to the solvent is 1:10-100.

[0014] Preferably, in step (1), the co-catalyst precursor comprises at least one of a metal oxide and a metal salt; wherein the metal element comprises at least one of zirconium, gallium, indium, lanthanum, cerium, titanium, magnesium, calcium, strontium, barium, niobium, iron, cobalt, nickel, manganese, zinc, aluminum, chromium, and cadmium. Among them, zirconium and gallium precursors are very suitable types, and the oxides generated by them are particularly suitable for the catalytic reduction of CO2 in the field.

[0015] Further preferably, the mass ratio of the metal element to copper is 1 to 60:100.

[0016] More preferably, the metal salt includes at least one of metal nitrate, metal chloride, metal sulfate, metal alkoxide, and metal acetylacetonate.

[0017] Preferably, in step (2), the concentration of the nitric acid aqueous solution is 0.1 to 14 mol / L; and the ratio of the molar amount of nitric acid added to the molar amount of the metal element in the co-catalyst precursor is 1 to 30:1.

[0018] Preferably, in step (2), the temperature of the etching reaction is 0 to 80° C., and the reaction time is 4 to 24 hours.

[0019] Preferably, in step (2), a structural additive is added during the etching reaction, and the structural additive includes at least one of cyanamide, dicyandiamide, melamine, diethylenediamine, and urea. Such structural additives can further increase the active sites at the oxide-copper interface and improve its dispersion.

[0020] More preferably, the mass ratio of copper to structural additive in the copper dispersion is 1:1-5.

[0021] Preferably, in step (3), the temperature of the thermal decomposition treatment is 280-700° C., and the treatment time is 2-18 hours.

[0022] The process of thermal decomposition and heating the catalyst to form the catalyst of the present invention is not limited by the gas atmosphere. Oxygen-containing gases such as oxygen and air, inert gases such as argon, nitrogen, and helium, and reducing gases such as hydrogen, carbon monoxide, and methane can be used.

[0023] In the second aspect of the present invention, a copper-based catalyst is provided, which is prepared by the method provided by the first aspect of the present invention and includes a copper support and a co-catalyst, wherein the co-catalyst is a metal oxide supported on the surface of the copper support.

[0024] Preferably, the specific surface area of ​​the copper-based catalyst is 1.2 to 70 m 2 / g.

[0025] In the structure of copper-based catalysts, small-particle oxides and metallic copper are tightly loaded on the surface of metallic copper and oxides, forming a rich oxide-copper catalytically active interface. The oxide acts as a protective layer to inhibit the sintering of copper powder.

[0026] In the third aspect of the present invention, there is provided an application of the copper-based catalyst of the second aspect of the present invention, specifically an application as a catalytic material in catalytic carbon dioxide reduction production.

[0027] Preferably, the specific method of the application is as follows: a copper-based catalyst is used as a catalytic material to catalyze the reaction of CO2 and H2 to produce methanol; wherein the reaction temperature is 180-350°C, the pressure is 0.1-5.1 MPa, and the space velocity is 1000-1000000h -1 .

[0028] At a certain temperature, pressure and space velocity, CO2 and H2 react to produce methanol. The reaction temperature should be set between 180 and 350 ° C. The reaction temperature is higher than 180 ° C to ensure that the activation rate of copper-catalyzed carbon dioxide molecules is fast enough. In addition, the reaction temperature is set below 350 ° C to prevent high temperature from causing irreversible damage to the catalyst structure. The pressure of the carbon dioxide reduction reaction is preferably set in the range of 0.1 to 5.1 MPa. A pressure higher than 0.1 MPa is conducive to the reaction equilibrium shifting towards the direction of methanol production. A pressure not higher than 5.1 MPa can save energy consumption caused by pressurization; the space velocity (GHSV) of the carbon dioxide reduction reaction should be between 1000 and 1000000h -1 Within the range, GHSV is set at 1000h -1The above can effectively prevent the generated methanol from being decomposed into CO, CO2 and hydrogen through the reverse reaction, and the GHSV is set at 1000000h -1 Hereby, the energy consumed for circulating the unreacted gas can be saved.

[0029] Based on the above technical solution, the concept and principle of the present invention is that the dispersant (such as oleylamine) can be coated on the surface of the copper powder particles so that they are suspended in a solvent (such as water), and can also protect their surface and delay the etching of nitric acid, so that a series of unstable copper sites can be selectively etched away, leaving copper sites with better stability. At the same time, the co-catalyst precursor will slowly hydrolyze in the solution to produce hydroxide colloid or precipitate, which is easier to be captured by the dispersant molecular groups coated on the surface of the copper particles or adsorbed on the dispersant groups in an ionic state. As the reaction proceeds, it is slowly fixed on the surface of the coated copper particles by a deposition precipitation method. In this way, after removing the solvent, by the method of thermal decomposition, it is possible to obtain highly dispersed metal oxides dispersed on the surface of the copper particles, as well as smaller copper particles deposited secondary. This preparation method can simultaneously achieve the construction of diverse copper-metal oxide interfaces by top-down (acid etching) and bottom-up (deposition precipitation) methods. The metal oxide is coated on the surface of the copper particles to form more copper-metal oxide active sites, and can effectively delay the sintering of active sites in the catalyst during continuous high-temperature reactions, thereby improving the durability of the catalyst.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] The invention provides a method for preparing a copper-based catalyst. The raw materials are easy to obtain and the process is simple and controllable.

[0032] The present invention provides a copper-based catalyst which is rich in copper-metal oxide interface, can alleviate the sintering of active sites in the catalyst during continuous high-temperature reactions, and has excellent catalytic performance and durability.

[0033] The present invention also provides an application of a copper-based catalyst for use in a reaction of reducing carbon dioxide, which has high catalytic activity and good safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is the X-ray diffraction (XRD) pattern of the copper-based catalyst prepared in Example 1; wherein a to h represent Cu, 1Ga1Zr / Cu, 3Ga1Zr / Cu, 8Ga1Zr / Cu, 11Ga1Zr / Cu, 8Ga3Zr / Cu, 8Ga6Zr / Cu, and 8Ga9Zr / Cu, respectively;

[0035] Figure 2This is a diagram showing the catalytic stability test results of 8Ga6Zr / Cu prepared in Example 1;

[0036] Figure 3 The X-ray diffraction (XRD) patterns of the copper-based catalyst prepared in Example 2; wherein a to d represent 8Ga6Zr / Cu+60MA, 8Ga6Zr / Cu+80MA, 8Ga6Zr / Cu+100MA, and 8Ga6Zr / Cu+140MA, respectively;

[0037] Figure 4 In the figure, (a) and (b) are transmission electron microscopy (TEM) and field emission transmission electron microscopy (FE-TEM) images of 8Ga6Zr / Cu+80MA prepared in Example 2, and (c) is its element distribution characteristics;

[0038] Figure 5 This is a catalytic stability test result diagram of 8Ga6Zr / Cu+80MA prepared in Example 2;

[0039] Figure 6 3 is the X-ray diffraction (XRD) pattern of the copper-based catalyst prepared in Example 3; wherein a and b represent 1Ni / Cu and 1Cd / Cu respectively. DETAILED DESCRIPTION

[0040] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0041] In the following embodiments:

[0042] Copper powder, particle size is 0.01-5 μm; oleylamine, analytical grade (98%), Aladdin Reagent (Shanghai) Co., Ltd.; hydrated gallium nitrate, zirconium nitrate pentahydrate, analytical grade (AR), Shanghai MacLean Biochemical Technology Co., Ltd.; nickel nitrate hexahydrate, cadmium nitrate tetrahydrate, analytical grade (AR), Sinopharm Chemical Reagent Co., Ltd.; constant temperature magnetic stirrer, DF-101S, Shanghai Lichen Instrument Technology Co., Ltd.; ultrasonic cleaner, KX-2013TD, Beijing Kexi Century Technology Co., Ltd.; X-ray powder diffractometer, X'Pert Pro, PANalytical, the Netherlands; specific surface area analyzer, BELSORP mini II, Japan Michiko Baier Co., Ltd.; muffle furnace, SG-XL1700, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences; gas chromatograph, GC-2020, Wuhan Taitworth Technology Co., Ltd.; transmission electron microscope, JEM-2100, Japan Electron Co., Ltd. (JEOL).

[0043] Example 1

[0044] The preparation method of the copper-based catalyst comprises the following steps:

[0045] (1) 0.5 g of copper powder was placed in a rotary evaporator, 10 mg of oleylamine was added, 0.5771 mmol of gallium nitrate and 0.3312 mmol of zirconium nitrate were added to the resulting mixture, and then distilled water was added to 10 mL. The mixture was stirred for 10 min and ultrasonicated at 60°C for 1 h to obtain a copper dispersion.

[0046] (2) adding 0.1 mol / L nitric acid aqueous solution dropwise to the obtained copper dispersion to control the total amount of nitric acid added to 1.0182 mmol, stirring in a 60° C. water bath to perform etching reaction for 24 h, and then removing the solvent by rotary evaporation to obtain a reaction product;

[0047] (3) The reaction product was transferred to a crucible, and then placed in a muffle furnace and calcined at 350 °C for 4 h to obtain a copper-based catalyst, which was designated as 8Ga6Zr / Cu, where the numbers represent the mass percentage of the corresponding metal element in Cu.

[0048] Using the same method, the addition amount of gallium nitrate and zirconium nitrate was adjusted to control the elemental ratio of gallium and zirconium in the resulting copper-based catalyst to obtain a new copper-based catalyst. Based on the content, this example prepared copper-based catalysts designated as 1Ga1Zr / Cu, 3Ga1Zr / Cu, 8Ga1Zr / Cu, 11Ga1Zr / Cu, 8Ga3Zr / Cu, 8Ga6Zr / Cu, and 8Ga9Zr / Cu. A catalyst (Cu) prepared from pure copper powder without the addition of gallium nitrate and zirconium nitrate was used as a control.

[0049] The copper-based catalysts prepared in this example were characterized by X-ray diffraction (XRD). Figure 1 As shown, the primary phases of the calcined catalyst are copper oxide and a small amount of cuprous oxide. Furthermore, in catalysts with increased promoter loading (such as 8Ga1Zr / Cu and 11Ga1Zr / Cu), some smaller copper nanoparticles are more easily encapsulated within the loaded oxide, inhibiting the aggregation and growth of metallic copper particles. Consequently, a small amount of unoxidized metallic copper remains after calcination.

[0050] Before the catalyst activity test, the catalyst was shaped to facilitate loading and prevent it from being blown away by gas. The above copper-based catalyst was granulated and screened, and 0.1g of catalyst with a particle size range of 0.22-0.45mm was taken and loaded into a stainless steel reaction tube for reduction, catalytic activity test and stability test.

[0051] Catalytic activity was tested using the internal standard method, using inert Ar as the internal standard gas. The relative contents of the reaction gas components were measured by gas chromatography, and the CO2 conversion and methanol selectivity were calculated. A reducing gas, H2 / Ar, was introduced into the reaction tube at a flow rate ratio of 9:1 (H2: 27 mL / min, Ar: 3 mL / min) at a pressure of 0.1 MPa. The temperature was raised to 350°C and reduced for 4 hours. The gas flow was then changed to a reactive gas, H2 / CO2 / Ar, at a flow rate ratio of 3:1:1 (H2: 36 mL / min, CO2: 12 mL / min, Ar: 12 mL / min) at a pressure of 1 MPa. A temperature control program was established, and at each test temperature, a 60-minute wait was performed before sampling and determination by gas chromatography. The CO2 conversion and methanol selectivity of the resulting copper-based catalyst are shown in Tables 1 and 2 below.

[0052] Table 1: Conversion of carbon dioxide over copper-based catalysts with different promoter contents

[0053]

[0054] Table 2: Methanol selectivity of carbon dioxide catalyzed by copper-based catalysts with different promoter contents

[0055]

[0056]

[0057] The stability test uses the same internal standard method. Using inert gas Ar as the internal standard substance, the relative content of the components in the reaction gas is determined by gas chromatography, and the conversion rate of carbon dioxide is calculated. The reducing gas H2 / Ar is introduced into the reaction tube at a gas flow rate ratio of 9:1, H2: 27mL / min, Ar: 3mL / min, and the pressure is 0.1MPa. After heating to 350℃ and reducing for 4h, the gas is changed to the reaction gas, that is, H2 / CO2 / Ar is introduced at a gas flow rate ratio of 3:1:1, H2: 36mL / min, CO2: 12mL / min, Ar: 12mL / min, and the pressure is 1MPa. The stability test is carried out at 270℃ for 72h, and continuous sampling and determination are performed by gas chromatography. The obtained stability test results are shown in Figure 2 .

[0058] From the above tests, it can be seen that the 8Ga6Zr / Cu catalyst is heated at 270℃ and the space velocity is 36000L·kg. cat -1 ·h -1 Under the conditions of 100 ℃ and 100 ℃, the space-time yield of methanol was maintained at 282.3±2.8g within 72h. MeOH kg cat -1 ·h -1, good stability.

[0059] Example 2

[0060] The preparation method of the copper-based catalyst comprises the following steps:

[0061] (1) 0.5 g of copper powder was placed in a rotary evaporator, 10 mg of oleylamine was added, 0.5771 mmol of gallium nitrate and 0.3312 mmol of zirconium nitrate were added to the resulting mixture, and then distilled water was added to 10 mL. The mixture was stirred for 10 min and ultrasonicated at 60°C for 1 h to obtain a copper dispersion.

[0062] (2) adding 0.1 mol / L nitric acid aqueous solution dropwise to the obtained copper dispersion to control the total amount of nitric acid added to 1.0182 mmol, stirring in a 60°C water bath to perform etching reaction for 12 hours, then adding 0.3 g of melamine (MA) and continuing the reaction for 12 hours. After completion, the solvent was removed by rotary evaporation to obtain a reaction product;

[0063] (3) The reaction product was transferred to a crucible, and then placed in a muffle furnace and calcined at 550°C for 4 h to obtain a copper-based catalyst, which was recorded as 8Ga6Zr / Cu+60MA, where the number before MA represents the mass percentage of melamine added to Cu.

[0064] The same method was used to adjust the amount of melamine added to obtain new copper-based catalysts. According to the addition amount, copper-based catalysts designated as 8Ga6Zr / Cu+60MA, 8Ga6Zr / Cu+80MA, 8Ga6Zr / Cu+100MA, and 8Ga6Zr / Cu+140MA were prepared in this example.

[0065] The copper-based catalysts prepared in this example were characterized by X-ray diffraction (XRD). Figure 3 As shown, it can be seen that the main phase of the calcined catalyst is copper oxide, and there are no diffraction peaks of cuprous oxide and metallic copper, indicating that the addition of structural additives helps to disperse copper species, promotes the dispersion of catalytic active sites, and inhibits the sintering of the catalyst.

[0066] The microstructure of 8Ga6Zr / Cu+80MA was observed and characterized. Figure 4 (a) Transmission electron microscopy (TEM) and Figure 4 From the field emission transmission electron microscopy (FE-TEM) image (b), it can be seen that the 8Ga6Zr / Cu+80MA catalyst forms a multi-level loading structure, which is characterized by small particles loaded on the surface of large particles, and small particles are tightly stacked to form large particles. Figure 4(c) Presents the elemental distribution characteristics of 8Ga6Zr / Cu+80MA determined by field emission transmission electron microscopy-energy spectrum analysis. The results show that it has a closely packed structure and an inlaid structure of gallium oxide, zirconium oxide and copper nanoparticles. The high-density interface sites thus formed are beneficial to inhibiting the sintering of the catalyst and improving the durability and catalytic activity of the catalyst.

[0067] After granulation and screening of the copper-based catalyst of this embodiment, 0.1 g of the catalyst with a particle size range of 0.22 to 0.45 μm was taken and placed in a stainless steel reaction tube. After reduction, catalytic activity test and stability test were performed.

[0068] The catalytic activity was tested using the internal standard method, using inert gas Ar as the internal standard gas. The relative contents of the reaction gas components were measured by gas chromatography, and the carbon dioxide conversion and methanol selectivity were calculated. A reducing gas, H2 / Ar, was introduced into the reaction tube at a flow rate ratio of 9:1 (H2: 27 mL / min, Ar: 3 mL / min) at a pressure of 0.1 MPa. The temperature was raised to 350°C and reduced for 4 hours. The gas was then changed to the reaction gas, i.e., H2 / CO2 / Ar, at a flow rate ratio of 3:1:1 (H2: 36 mL / min, CO2: 12 mL / min, Ar: 12 mL / min) at a pressure of 1 MPa. The temperature control program was set, and at each test temperature, a 60-minute wait was performed before sampling and determination by gas chromatography. The carbon dioxide conversion and methanol selectivity of the copper-based catalyst obtained in this example are shown in Tables 3 and 4 below.

[0069] Table 3: Conversion of carbon dioxide by copper-based catalysts with different melamine addition amounts

[0070]

[0071] Table 4: Methanol selectivity of carbon dioxide catalyzed by copper-based catalysts with different melamine addition amounts

[0072]

[0073]

[0074] The stability test uses the same internal standard method. Using inert gas Ar as the internal standard substance, the relative content of the components in the reaction gas is determined by gas chromatography, and the conversion rate of carbon dioxide is calculated. The reducing gas H2 / Ar is introduced into the reaction tube at a gas flow rate ratio of 9:1, H2: 27mL / min, Ar: 3mL / min, and the pressure is 0.1MPa. After heating to 350℃ and reducing for 4h, the gas is changed to the reaction gas, that is, H2 / CO2 / Ar is introduced at a gas flow rate ratio of 3:1:1, H2: 36mL / min, CO2: 12mL / min, Ar: 12mL / min, and the pressure is 1MPa. The stability test is carried out at 270℃ for 72h, and continuous sampling and determination are carried out by gas chromatography.

[0075] The stability test results are as follows Figure 5 As shown. 8Ga6Zr / Cu+80MA catalyst at 270℃, space velocity 36000L·kg cat -1 ·h -1 Under the conditions of 100 ℃ and 100 ℃, the space-time yield of methanol was maintained at 348.9±7.7 g within 72 h. MeOH kg cat -1 ·h -1 The results show that the addition of structural additives such as melamine can further improve the dispersion of catalytic active sites, form high-density interfacial sites, inhibit catalyst sintering, and improve catalyst durability and catalytic activity.

[0076] Example 3

[0077] The preparation method of the copper-based catalyst comprises the following steps:

[0078] (1) 0.5 g of copper powder was placed in a rotary evaporator, 10 mg of oleylamine was added, 0.0852 mmol of nickel nitrate (or 0.0445 mmol of cadmium nitrate) was added to the resulting mixture, and then distilled water was added to 10 mL. The mixture was stirred for 10 min and ultrasonicated at 60°C for 1 h to obtain a copper dispersion.

[0079] (2) adding 0.1 mol / L nitric acid aqueous solution dropwise to the obtained copper dispersion to control the total amount of nitric acid added to 1.0182 mmol, stirring in a 60° C. water bath to perform etching reaction for 24 h, and then removing the solvent by rotary evaporation to obtain a reaction product;

[0080] (3) The reaction product was transferred to a crucible, and then placed in a muffle furnace and calcined at 350 °C for 4 h to obtain a copper-based catalyst, which was recorded as 1Ni / Cu (or 1Cd / Cu), where the number represents the mass percentage of the corresponding metal element in Cu.

[0081] The copper-based catalyst prepared in this example was characterized by X-ray diffraction (XRD). Figure 6 As shown, it can be seen that the main phase of the calcined catalyst is copper oxide, and there are no diffraction peaks of other phases, indicating that the co-catalyst is highly dispersed or amorphous. These characteristics are conducive to the dispersion of copper species, promote the formation of high-density catalytic active sites, and inhibit the sintering of the catalyst.

[0082] The above copper-based catalyst was granulated and screened, and 0.1 g of the catalyst with a particle size range of 0.22 to 0.45 mm was taken and loaded into a stainless steel reaction tube for reduction, catalytic activity test and stability test.

[0083] Catalytic activity was tested using the internal standard method, using inert Ar as the internal standard gas. The relative contents of the reaction gas components were measured by gas chromatography, and the CO2 conversion and methanol selectivity were calculated. A reducing gas, H2 / Ar, was introduced into the reaction tube at a flow rate ratio of 9:1 (H2: 27 mL / min, Ar: 3 mL / min) at a pressure of 0.1 MPa. The temperature was raised to 350°C and reduced for 4 hours. The gas was then changed to a reactant gas, H2 / CO2 / Ar, at a flow rate ratio of 3:1:1 (H2: 36 mL / min, CO2: 12 mL / min, Ar: 12 mL / min) at a pressure of 1 MPa. A temperature control program was established, and at each test temperature, a 60-minute wait was performed before sampling and determination by gas chromatography. The CO2 conversion of the resulting copper-based catalyst increased with increasing temperature, while its methanol selectivity decreased. The results are shown in Tables 5 and 6 below.

[0084] Table 5: Conversion of carbon dioxide over copper-based catalysts

[0085]

[0086] Table 6: Methanol selectivity of carbon dioxide over copper-based catalysts

[0087]

[0088] The above test results show that the technical purpose of the present invention can also be achieved under other parameter selections.

[0089] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a copper-based catalyst, characterized in that: The steps include: (1) mixing powdered copper with a dispersant and a solvent, adding a co-catalyst precursor that can be hydrolyzed to form a metal hydroxide colloid or precipitate to the resulting mixture, and continuing to mix to obtain a copper dispersion; The copper has a particle size of 0.01 to 5 μm; the dispersant is an organic base, including at least one of oleylamine, ethylenediamine, and isopropanolamine; the solvent includes at least one of water, oleylamine, oleic acid, ethylenediamine, tetrahydrofuran, ethanol, and methanol; the mass ratio of the dispersant to copper is 0.1 to 10:100, and the mass ratio of the copper to the solvent is 1:10 to 100; the co-catalyst precursor includes at least one of a metal oxide and a metal salt; wherein the metal element includes at least one of zirconium, gallium, indium, lanthanum, cerium, titanium, magnesium, calcium, strontium, barium, niobium, iron, cobalt, nickel, manganese, zinc, aluminum, chromium, and cadmium; the mass ratio of the metal element to copper is 1 to 60:100; the metal salt includes at least one of a metal nitrate, a metal chloride, a metal sulfate, a metal alkoxide, and a metal acetylacetonate; (2) adding a nitric acid aqueous solution to the copper dispersion and performing an etching reaction, and removing the solvent after completion to obtain a reaction product; the concentration of the nitric acid aqueous solution is 0.1 to 14 mol / L; the ratio of the molar amount of nitric acid added to the molar amount of the metal element in the co-catalyst precursor is 1 to 30:1; the temperature of the etching reaction is 0 to 80 ° C, and the reaction time is 4 to 24 h; a structural additive is added during the etching reaction, and the structural additive includes at least one of monocyanamide, dicyandiamide, melamine, diethylenediamine, and urea; the mass ratio of copper in the copper dispersion to the structural additive is 1:1 to 5; (3) The reaction product is subjected to thermal decomposition treatment to obtain a copper-based catalyst; the thermal decomposition treatment temperature is 280-700°C, and the treatment time is 2-18 hours.

2. A copper-based catalyst, characterized in that: The method according to claim 1 is used to prepare the catalyst, comprising a copper carrier and a promoter, wherein the promoter is a metal oxide supported on the surface of the copper carrier.

3. A use of the copper-based catalyst as claimed in claim 2, characterized in that: Application as catalytic material in catalytic carbon dioxide reduction production.

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