Cu-Al-Ni-Co-based catalyst, and preparation method thereof and use thereof

Abstract

Disclosed in the present application are a Cu-Al-Ni-Co-based catalyst, and a preparation method therefor and the use thereof. The composition of the Cu-Al-Ni-Co-based catalyst of the present applicati

Description

5 The present disclosure relates to the technical field of battery material recycling, and in particular to a Cu-Al-Ni-Co-based catalyst, and a preparation method and a use thereof. BACKGROUND Due to the rapid industrial development, the emission of carbon dioxide in the atmosphere is 10 increasing. The increasing concentration of carbon dioxide in the atmosphere requires a new method to capture, sequester, and utilize carbon dioxide. At present, carbon dioxide recycling technologies have received extensive attention, among which the catalytic hydrogenation of carbon dioxide to produce a value-added product such as methane, syngas, methanol, and dimethyl ether is considered as an efficient way to utilize carbon dioxide. However, a catalyst for the catalytic hydrogenation of carbon dioxide to produce a value-added product needs to be prepared with a high cost and a complicated process, and has poor selectivity. It is urgent to develop an environmentally-friendly, simple, and low-cost preparation method. Lithium-ion batteries (LIBs) have a service life of about 3 to 20 years. With the increasing demand for LIBs, an amount of waste batteries to be recycled has been increased sharply. However, 20 waste LIBs easily cause environmental pollution, and how to dispose of waste batteries on a large scale is a very challenging problem. Moreover, a copper-aluminum slag produced in a recycling process of waste LIB materials usually includes elements such as Cu, Al, Ni, and Co, and a recovery process of these metal elements is generally complicated and costly, which is not conducive to large-scale disposal and practical application. 25 Therefore, there is an urgent need to develop an environmentally-friendly and economical approach that can not only recycle a waste battery material on a large scale, but also utilize carbon dioxide as a resource. WO2021262922A1 provides catalysts, comprising : copper; zinc; one or more first elements selected from iron, nickel, or cobalt; aluminum; oxygen; optionally, one or more second elements 30 selected from a Group V, VI, VII, VIII, IX, X, and XI metal (e.g., manganese, silver, niobium, zirconium, molybdenum, ruthenium, or palladium); and optionally, one or more Group IA metals, 27 02 25 and wherein the first element is present in an amount of about 1 to about 40 wt.% (e.g., about 1 to about 10 wt.%, about 25 to about 40 wt.%, about 30 to about 40 wt.%, or about 35 to about 40 wt.%) of the total amount of the copper, zinc, first element, the optional second element, and the optional Group IA metal, and methods of using said catalyst in the production of ethanol and higher alcohols 5 from carbon dioxide. SUMMARY The following is a summary of the subject matters described in detail herein. This summary is not intended to limit the protection scope of the claims. 10 In order to develop an environmentally-friendly and economical approach that can recycle a waste battery material on a large scale and utilize carbon dioxide as a resource so to achieve the recycling of both carbon dioxide and a waste battery material, a first objective of the present disclosure is to provide a Cu-Al-Ni-Co-based catalyst. A second objective of the present disclosure is to provide a preparation method of the Cu-Al-Ni-Co-based catalyst. A third objective of the present disclosure is to provide a use of the Cu-Al-Ni-Co-based catalyst. The technical solutions of the present disclosure are as follows. In a first aspect, the present disclosure provides a Cu-Al-Ni-Co-based catalyst, including: CuO, AI2O3, CO3O4, NiO, MnO?, Li2O, and Fe2O3; 20 an atomic mass fraction of Cu, Al, Ni, and Co in the Cu-Al-Ni-Co-based catalyst may be as follows: Cu: 21% to 23%; Al: 24% to 25%; Ni: 1.2% to 1.6%; and 25 Co: 15% to 16%. Preferably, the CuO may include a (-1 1 1) crystal plane, and the crystal plane may have an interplanar spacing of 2 nm to 3 nm. Specifically, the Cu-Al-Ni-Co-based catalyst includes a variety of active components, so that there are abundant basic sites and reduction reaction sites, which is conducive to the adsorption and 30 desorption of hydrogen and thus is suitable for a catalytic hydrogenation reaction system. In a second aspect, the present disclosure provides a preparation method of a Cu-Al-Ni-Co-based catalyst, including the following steps: 27 02 25 dissolving a copper-aluminum slag produced in an LIB recycling process in an acid, adding an alkali to allow a co-precipitation reaction, separating a resulting precipitate, and subjecting the resulting precipitate to calcination to obtain the Cu-Al-Ni-Co-based catalyst; wherein copper, aluminum, cobalt, and nickel in the copper-aluminum slag may have a mass 5 ratio of (8 to 30):(10 to 30):(5 to 20): 1; the co-precipitation reaction is conducted for 2 h to 3 h at a temperature of 50°C to 80°C and a pH of 6 to 8. Preferably, the preparation method of the Cu-Al-Ni-Co-based catalyst may include the following steps: 10 dissolving a copper-aluminum slag produced in an LIB recycling process in an acid solution, adding an alkali solution to allow a co-precipitation reaction, separating a resulting precipitate, and subjecting the resulting precipitate to calcination to obtain the Cu-Al-Ni-Co-based catalyst. Further preferably, the copper, aluminum, cobalt, and nickel in the copper-aluminum slag may have a mass ratio of (10 to 25):(15 to 26):(6 to 18):1. Further preferably, the acid may be one or more selected from the group consisting of nitric acid, hydrochloric acid, and sulfuric acid. Further preferably, the alkali may be one or more selected from the group consisting of ammonium hydroxide, sodium hydroxide, and potassium hydroxide. Preferably, the acid solution may have a concentration of 1 mol / L to 3 mol / L, and the alkali 20 solution may have a concentration of 1 mol / L to 3 mol / L. Preferably, stirring may be conducted during the co-precipitation reaction. Preferably, the co-precipitation reaction is further followed by standing, and the standing may be conducted at 15°C to 35°C for 1 h to 3 h. Preferably, the separating may be specifically implemented by suction filtration. 25 Preferably, separating the precipitate is further followed by washing and drying. Preferably, the drying may be conducted at 50°C to 100°C. Further preferably, the calcination may be conducted at 400°C to 600°C for 1 h to 3 h. Preferably, the calcination may be conducted at a heating rate of Se inin'1 to 10°C min’1. In a third aspect, the present disclosure provides a method for synthesizing methanol with carbon 30 dioxide, including the following steps: 1) filling the Cu-Al-Ni-Co-based catalyst according to the first aspect into a reactor, and introducing a reducing gas for activation; and 2) introducing the carbon dioxide and hydrogen into the reactor, and conducting a catalytic reaction to obtain the methanol; wherein the catalytic reaction in step 2) is conducted at 200°C to 300°C, the catalytic reaction in step 2) is conducted at 1 MPa to 5 MPa, and the catalytic reaction in step 2) is conducted at a space 5 velocity of 6,000 h'1 to 15,000 h'1. Preferably, the Cu-Al-Ni-Co-based catalyst in step 1) may need sieving, granulating, and diluting steps before being filled into the reactor. Preferably, the sieving may be conducted with a 10 to 100-mesh sieve. Preferably, the diluting may be specifically conducted by mixing a diluent with the Cu-Al-Ni-10 Co-based catalyst. Preferably, a mass ratio of the diluent to the Cu-Al-Ni-Co-based catalyst may be 1:1 to 1:5. Further preferably, a mass ratio of the diluent to the Cu-Al-Ni-Co-based catalyst may be 1:2 to 1:3. Preferably, the diluent may have a mesh number of 10 to 100. Preferably, the diluent may be at least one selected from the group consisting of quartz sand, molecular sieve, and activated carbon. Further preferably, the diluent may be quartz sand. Preferably, a flow rate of the reducing gas in step 1) may be 30 mLmin'1 to 100 mLmin'1. Further preferably, a flow rate of the reducing gas in step 1) may be 40 mL min'1 to 60 mLmin' Preferably, the reducing gas in step 1) may be hydrogen and / or carbon monoxide. Further preferably, the reducing gas in step 1) may be hydrogen. Preferably, the activation in step 1) may be conducted at 300°C. Preferably, the activation in step 1) may be conducted at a heating rate of 5°C min'1 to 10°Cmin' Preferably, the activation in step 1) may be conducted for 0.5 h to 5 h. Further preferably, the activation in step 1) may be conducted for 1 h to 3 h. Preferably, in step 2), a volume ratio of the carbon dioxide to the hydrogen may be 1:1 to 1:10. Further preferably, in step 2), the volume ratio of the carbon dioxide to the hydrogen may be 1:2 30 to 1:5. Preferably, in step 2), the carbon dioxide may have a volume concentration of 5% to 30% during 27 02 25 -5-the catalytic reaction. More preferably, in step 2), the carbon dioxide may have a volume concentration of 10% to 20% during the catalytic reaction. Further more preferably, in step 2), the carbon dioxide may have a volume concentration of 15% 5 during the catalytic reaction. Preferably, in step 2), a protective gas may also be introduced into the reactor. Preferably, the protective gas may be one or more selected from the group consisting of helium, nitrogen, argon, and neon. More preferably, the catalytic reaction in step 2) may be conducted at 240°C to 280°C. 10 Further more preferably, the catalytic reaction in step 2) may be conducted at 260°C. Preferably, gas chromatography (GC) may be used to monitor a reactant and a product of the catalytic reaction. The present disclosure has the following beneficial effects. The Cu-Al-Ni-Co-based catalyst of the present disclosure includes abundant active components and reaction sites (including a variety of basic sites), and shows a prominent catalytic effect as a catalyst for carbon dioxide hydrogenation; and the catalyst is prepared from a waste battery material, which realizes the recycling of the waste battery material, has the advantages of simple preparation and environmental friendliness, and is suitable for practical applications. Specifically: 20 (1) In the present disclosure, a waste battery material is recycled to prepare a catalyst product, which realizes the change from waste to treasure. (2) The Cu-Al-Ni-Co-based catalyst of the present disclosure has abundant reduction sites and basic sites and shows high activity when used for converting carbon dioxide into methanol, so that the waste battery material can be recycled, and the carbon dioxide can be comprehensively utilized 25 to synthesize a chemical value-added product (methanol fuel). (3) The Cu-Al-Ni-Co-based catalyst of the present disclosure can catalyze the hydrogenation of carbon dioxide at 200°C to 300°C to produce methanol (fuel), and shows high selectivity and prominent stability at a reaction temperature of 240°C to 280°C, that is, the methanol selectivity is about 75%, and the stability is high during the reaction at 260°C for 60 h. 30 (4) The method for synthesizing methanol from carbon dioxide provided by the present disclosure includes activation, which helps to improve the stability of the Cu-Al-Ni-Co-based catalyst in the catalytic reaction, thereby improving a service life of the catalyst. 27 02 25 After reading and understanding the drawings and the detailed description, other aspects can be understood. BRIEF DESCRIPTION OF DRAWINGS 5 Drawings are provided for further understanding of the technical schemes of the present disclosure and constitute a part of the specification, and together with the embodiments are used for explaining the technical schemes of the disclosure, which do not limit the technical schemes of the disclosure. FIG. 1 shows an X-ray diffractometry (XRD) pattern of the Cu-Al-Ni-Co-based catalyst in 10 Example 1. FIG. 2 shows a transmission electron microscopy (TEM) image of the Cu-Al-Ni-Co-based catalyst in Example 1. FIG. 3 shows a high-resolution transmission electron microscopy (HRTEM) image of the Cu-Al-Ni-Co-based catalyst in Example 1. FIG. 4 shows a reaction temperature-CCE conversion rate curve of the Cu-Al-Ni-Co-based catalyst in Example 1. FIG. 5 shows a reaction temperature-methanol yield curve of the Cu-Al-Ni-Co-based catalyst in Example 1. FIG. 6 shows a reaction temperature-methanol selectivity curve of the Cu-Al-Ni-Co-based 20 catalyst in Example 1. FIG. 7 shows the stability test results of the Cu-Al-Ni-Co-based catalyst in Example 1. DETAILED DESCRIPTION The content of the present disclosure will be further described in detail below through specific 25 examples. Example 1 A preparation method of a Cu-Al-Ni-Co-based catalyst was provided, including the following steps: 1) 20 g of a copper-aluminum slag was dissolved in 3 molL'1 nitric acid to obtain a Cu-Al-Ni-30 Co-containing mixed solution (denoted as solution A), and then a 3 molL'1 ammonium hydroxide solution (denoted as solution B) was prepared; 2) the solution A and the solution B were simultaneously added dropwise to a beaker in a water bath at 80°C to allow a co-precipitation reaction, during which dropwise addition rates of the solution A and the solution B were controlled to maintain a pH of a reaction solution at about 8; and the reaction solution was continuously stirred for 3 h in the water bath, and then stood at room temperature for 1 h to obtain a suspension; and 5 3) the suspension obtained in step 2) was subjected to suction filtration, and a resulting filter residue was washed with deionized water, dried at 90°C for 12 h, calcined at 600°C for 3 h, and then granulated and sieved (20 to 40 mesh) to obtain the Cu-Al-Ni-Co-based catalyst. A method for the catalytic synthesis of methanol from carbon dioxide was provided, including the following steps: 10 1) pre-activation of the catalyst: 1.5 g of the Cu-Al-Ni-Co-based catalyst and 4.5 g of inert silica sand (20 to 40 mesh) were thoroughly mixed and added to a reactor, then hydrogen was introduced, and a resulting mixture was treated at 300°C for 1 h (with a heating rate of 10°Cmin'1 and a gas flow rate of 50 mLmin'1); and 2) preparation of methanol: a mixed gas of 15% CO2, 45% H2, and Ar was introduced into the reactor, and with a space velocity of 12,000 h’1, a pressure of 5 Mpa, and a heating rate of 5°C min'1, a reaction was conducted at 200°C to 300°C to obtain the methanol. Characterization and performance testing: 1) Element contents of the Cu-Al-Ni-Co-based catalyst in Example 1 were determined by inductively coupled plasma mass spectrometry (ICP-MS), and results were shown in Table 1. 20 It can be seen from Table 1 that the catalyst prepared by recycling a copper-aluminum slag includes a large amount of Cu (22.66%), Al (24.13%), and Co (15.17%) and a small amount of Ni (1.4%). Because H2 is mainly decomposed on Cu and Ni and CO2 is mainly activated on Al and Co, the Cu-Al-Ni-Co-based catalyst of the present disclosure is beneficial to the conversion of carbon dioxide into methanol. 25 Table 1 Element contents of the Cu-Al-Ni-Co-based catalyst in Example 1 Element Ni Co Cu Al Mn Li Fe Mass percentage 1.4% 15,17% 22,66% 24,13% 0,88% 3,19% 0,03% 2) An XRD pattern of the Cu-Al-Ni-Co-based catalyst in Example 1 was determined, as shown in FIG. 1. It can be seen from FIG. 1 that the components in the Cu-Al-Ni-Co-based catalyst mainly exist in the form of oxides; diffraction peaks at 35.5°, 38.75°, and 48.75° are attributed to CuO (PDF# 72- 30 0629); diffraction peaks at 35.16°, 58.24°, and 68.18° are attributed to AI2O3 (PDF# 75-0786); and characteristic diffraction peaks of NiO (PDF#87-0712) and CO3O4 (PDF#76-1802) can also be 27 02 2S 27 02 25 -8-observed clearly. This shows that a Cu-Al-Ni-Co-based catalyst containing CuO, CO3O4, AI2O3, and NiO can be prepared from a copper-aluminum slag of a waste battery in the present disclosure. CuO and NiO also show a disassociation effect for hydrogen on the catalyst after carbon dioxide reduction, and AI2O3 and CO3O4 show an adsorption effect for the reactant CO2. Further, from the perspective 5 of kinetics, the improvement on the adsorption for CO2 and the disassociation for hydrogen is beneficial to the generation of methanol. 3) A TEM image and an HRTEM image of the Cu-Al-Ni-Co-based catalyst in Example 1 were shown in FIG. 2 and FIG. 3, respectively. It can be seen from FIG. 2 and FIG. 3 that a dark part in FIG. 2 is mainly an area where CuO is 10 distributed, and CuO is distributed on the Cu-Al-Ni-Co-based catalyst with high dispersibility, which facilitates the disassociation of H2, thereby promoting the synthesis of methanol. According to further analysis of the dark area, an obvious (-1 1 1) crystal plane of CuO can be observed in FIG. 3, and an interplanar spacing is 2.522 nm, which further verifies that there is a CuO phase with high dispersibility and crystallinity on the Cu-Al-Ni-Co-based catalyst. 15 4) Under the reaction conditions of the method for the catalytic synthesis of methanol from carbon dioxide, the catalytic activity of the Cu-Al-Ni-Co-based catalyst in Example 1 was determined at a reaction temperature ranging from 200°C to 300°C (activity evaluation indexes were as follows: CO2 conversion rate, methanol yield, and methanol selectivity), and results were shown in FIG. 4, FIG. 5, and FIG. 6. The Cu-Al-Ni-Co-based catalyst was allowed to participate in a reaction at 260°C continuously for 60 h to obtain the stability test results of the Cu-Al-Ni-Co-based catalyst in Example 1, as shown in FIG. 7. It can be seen from FIG. 4, FIG. 5, and FIG. 6 that, in a reaction temperature range of 200°C to 260°C, with the increase of the reaction temperature, the CO2 conversion rate and the methanol yield increase rapidly; in a reaction temperature range of 260°C to 300°C, with the increase of the reaction 25 temperature, the CO2 conversion rate shows a slow increase trend (the CO2 conversion rate at 300°C is 9.8%), and the methanol yield shows a slow decline trend (the methanol yield at 260°C is 64.8%); and in a reaction temperature range of 200°C to 300°C, the methanol selectivity decreases continuously. In conclusion, it is economical to synthesize methanol with the Cu-Al-Ni-Co-based catalyst at about 260°C (the methanol selectivity is about 75%). At 260°C, the catalyst can only 30 achieve a CO2 conversion rate of 9.8%, but leads to a methanol yield of 64.8%, which can achieve the effect of capturing carbon dioxide and converting the carbon dioxide into methanol with a high economic value. It can be seen from FIG. 7 that, according to the stability test of the Cu-Al-Ni-Co-based catalyst at 260°C for 60 h, the stability of the catalyst is high, the CO2 conversion rate is maintained at about 8%, and the methanol yield is maintained at about 75%, which is suitable for the actual production and application of methanol. Example 2 A preparation method of a Cu-Al-Ni-Co-based catalyst was provided, including the following 5 steps: 1) 20 g of a copper-aluminum slag was dissolved in 2 molL'1 nitric acid to obtain a Cu-Al-Ni-Co-containing mixed solution (denoted as solution A), and then a 2 molL'1 ammonium hydroxide solution (denoted as solution B) was prepared; 2) the solution A and the solution B were simultaneously added dropwise to a beaker in a water 10 bath at 60°C to allow a co-precipitation reaction, during which dropwise addition rates of the solution A and the solution B were controlled to maintain a pH of a reaction solution at about 7; and the reaction solution was continuously stirred for 2 h in the water bath, and then stood at room temperature for 1 h to obtain a suspension; 3) the suspension obtained in step 2) was subjected to suction filtration, and a resulting filter residue was washed with deionized water, dried at 100°C for 12 h, calcined at 500°C for 3 h, and then granulated and sieved (20 to 40 mesh) to obtain the Cu-Al-Ni-Co-based catalyst. A method for the catalytic synthesis of methanol from carbon dioxide was provided, including the following steps: 1) pre-activation of the catalyst: 1 g of the Cu-Al-Ni-Co-based catalyst and 3 g of inert silica 20 sand (20 to 40 mesh) were thoroughly mixed and added to a reactor, then hydrogen was introduced, and a resulting mixture was treated at 300°C for 1 h (with a heating rate of 10°Cmin'1 and a gas flow rate of 50 mLmin'1); and 2) preparation of methanol: a mixed gas of 15% CO2, 45% H2, and Ar was introduced into the reactor, and with a space velocity of 10,000 h'1, a pressure of 3 Mpa, and a heating rate of 5°C min'1, 25 a reaction was conducted at 200°C to 300°C to obtain the methanol. According to test results, the phase composition and performance of the catalyst prepared in this example (the methanol yield at 260°C is 63.5%) are very similar to that of the catalyst prepared in Example 1. Example 3 30 A preparation method of a Cu-Al-Ni-Co-based catalyst was provided, including the following steps: 1) 20 g of a copper-aluminum slag was dissolved in ImolL'1 nitric acid to obtain a Cu-Al-Ni-Co-containing mixed solution (denoted as solution A), and then a ImolL'1 ammonium hydroxide 27 02 25 -10-solution (denoted as solution B) was prepared; 2) the solution A and the solution B were simultaneously added dropwise to a beaker in a water bath at 50°C to allow a co-precipitation reaction, during which dropwise addition rates of the solution A and the solution B were controlled to maintain a pH of a reaction solution at about 6; and the 5 reaction solution was continuously stirred for 3 h in the water bath, and then stood at room temperature for 2 h to obtain a suspension; 3) the suspension obtained in step 2) was subjected to suction filtration, and a resulting filter residue was washed with deionized water, dried at 80°C for 12 h, calcined at 400°C for 3 h, and then granulated and sieved (20 to 40 mesh) to obtain the Cu-Al-Ni-Co-based catalyst. 10 A method for the catalytic synthesis of methanol from carbon dioxide was provided, including the following steps: 1) pre-activation of the catalyst: 0.5 g of the catalyst and 1.5 g of inert silica sand (20 to 40 mesh) were thoroughly mixed and added to a reactor, then hydrogen was introduced, and a resulting mixture was treated at 300°C for 2 h (with a heating rate of 10°Cmin'1 and a gas flow rate of 50 mL min'1); and C\J 2) preparation of methanol: a mixed gas of 15% CO2, 45% H2, and Ar was introduced into the reactor, and with a space velocity of 6,000 h'1, a pressure of 2 Mpa, and a heating rate of 10°C min'1, a reaction was conducted at 200°C to 300°C to obtain the methanol. h- According to test results, the phase composition and performance of the Cu-Al-Ni-Co-based catalyst prepared in this example (the methanol yield at 260°C is 64.2%) are very similar to that of the catalyst prepared in Example 1. Comparative Example A preparation method of a Cu-Al-Ni-Co-based catalyst was provided in this comparative example, which was different from the examples in that a copper-aluminum slag was simply 25 activated, specifically including the following steps: 1.5 g of the copper-aluminum slag and 4.5 g of inert silica sand (20 to 40 mesh) were thoroughly mixed and added to a reactor, then hydrogen was introduced, and a resulting mixture was treated at 300°C for 1 h (with a heating rate of 10°Cmin'1 and a gas flow rate of 50 mL min'1) to obtain a catalyst. 30 The catalyst in this comparative example was subjected to a performance test, and specific test conditions were the same as the conditions for methanol preparation in the examples. From the performance test, it can be seen that there is no methanol in a collected reaction product, and the CO2 conversion rate is zero; indicating that the catalyst obtained through the simple -11-activation in this comparative example does not have the ability to capture, collect, store, and convert CO2 and cannot regenerate a waste battery material (copper-aluminum slag). That is, a catalyst capable of converting carbon dioxide into methanol cannot be obtained. Unless otherwise specified, an amount of each of reactants (hydrogen and carbon dioxide) and 5 products (methanol) in the method for the catalytic synthesis of methanol from carbon dioxide in Examples 1 to 3 and the performance tests in the comparative example was tested and analyzed using a gas chromatograph with a thermal conductivity detector (TCD) and a flame ionization detector (FID) (Agilent Technologies 6890 USA). 27 02 25 27 02 25

Claims

1. A Cu-Al-Ni-Co-based catalyst, comprising: CuO, AI2O3, CO3O4, NiO, MnO2, Li2O, and Fe2O3;an atomic mass fraction of Cu, Al, Ni, and Co in the Cu-Al-Ni-Co-based catalyst are as follows:5 Cu: 21% to 23%;Al: 24% to 25%;Ni: 1.2% to 1.6%; andCo: 15% to 16%.

2. A preparation method of a Cu-Al-Ni-Co-based catalyst, comprising the following steps:10 dissolving a copper-aluminum slag produced in a lithium-ion battery recycling process in an acid, adding an alkali to allow a co-precipitation reaction, separating a resulting precipitate, and subjecting the resulting precipitate to calcination to obtain the Cu-Al-Ni-Co-based catalyst;wherein copper, aluminum, cobalt, and nickel in the copper-aluminum slag have a mass ratio of (8 to 30):(10 to 30):(5 to 20): 1;the co-precipitation reaction is conducted for 2 h to 3 h at a temperature of 50°C to 80°C and a pH of 6 to 8.

3. The preparation method of the Cu-Al-Ni-Co-based catalyst according to claim 2, wherein the acid is one or more selected from the group consisting of nitric acid, hydrochloric acid, and sulfuric acid; and the alkali is one or more selected from the group consisting of ammonium hydroxide, 20 sodium hydroxide, and potassium hydroxide.

4. The preparation method of the Cu-Al-Ni-Co-based catalyst according to claim 3, wherein the acid has a concentration of 1 mol / L to 3 mol / L, and the alkali has a concentration of 1 mol / L to 3 mol / L.

5. The preparation method of the Cu-Al-Ni-Co-based catalyst according to any one of claims 2 25 to 3, wherein the calcination is conducted at 400°C to 600°C for 1 h to 3 h.

6. A method for synthesizing methanol with carbon dioxide, comprising the following steps:1) filling the Cu-Al-Ni-Co-based catalyst according to any one of claim 1 into a reactor, and introducing a reducing gas for activation; and2) introducing the carbon dioxide and hydrogen into the reactor, and conducting a catalytic 30 reaction to obtain the methanol;wherein the catalytic reaction in step 2) is conducted at 200°C to 300°C, the catalytic reactionin step 2) is conducted at 1 MPa to 5 MPa, and the catalytic reaction in step 2) is conducted at a space velocity of 6,000 h'1 to 15,000 h’1.

7. The method for synthesizing methanol with carbon dioxide according to claim 6, wherein the activation in step 1) is conducted at 300°C.27 02 25

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