Preparation method and application of CuZnZr catalyst for carbon dioxide hydrogenation to methanol

Abstract

The application discloses a preparation method and application of a CuZnZr catalyst for carbon dioxide hydrogenation to methanol. Copper nitrate, zirconium nitrate and zinc nitrate are used as raw materials, and sodium carbonate is added drop by drop at a slow rate, and then Cu1-ZrO2 single-atom catalyst, Cu-ZnZrOx catalyst, Cu-ZnO catalyst and Cu-ZnO catalyst and other catalysts with clearly defined active sites are prepared through precipitation, aging, filtration, drying and low-temperature calcination. 0 0 0 The preparation method is simple, safe and highly repeatable, and is suitable for industrial application. Active metal copper species in the obtained catalyst exists in multiple states, metal oxides on the catalyst and metal Cu species have different interaction degrees, and different catalytic reaction active sites are generated. The CuZnZr catalyst contains four clearly defined active sites, and carbon dioxide can be selectively reduced to methanol at low temperature.​​

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of metal-supported catalyst preparation and heterogeneous energy catalysis, and particularly relates to preparation of a CuZnZr catalyst containing well-defined active sites and application of the catalyst in carbon dioxide hydrogenation to methanol. BACKGROUND

[0002] With the progress and development of society, the global carbon dioxide emissions have reached an unprecedented level. A series of ecological and environmental problems caused by excessive carbon dioxide emissions seriously endanger human survival and development, and the carbon emission problem must be solved without delay. Although the CCS technology based on carbon dioxide capture and storage can capture and store a large amount of carbon dioxide, the CCUS technology for carbon dioxide reuse has more economic value and sustainability, and is currently the most effective carbon reduction and carbon negative technology recognized by the world. Converting excessive carbon dioxide emissions into high-value chemical products and energy fuels not only can effectively alleviate the greenhouse effect, but also fully embodies the reuse of carbon dioxide in the field of economic value. In particular, the catalytic hydrogenation of CO2 to CH3OH has great commercial value. Methanol is the main raw material for industrial synthesis, and has rich downstream products and high utilization value, such as dimethyl ether, formaldehyde, MTBE, etc. In addition, the methanol industry is an important industry in the national economy. The methanol industry is not only a basic industry, but has also developed into an important field of the national economy.

[0003] Cu / ZnO / Al2O3, a commercially available catalyst for methanol production invented by ICI in the 1970s, has attracted considerable attention since then. Research on its active sites has been ongoing, leading to a series of Cu-based catalysts using diverse supports, including oxygen-vacant supports such as ZnO, ZrO2, CeO2, and TiO2, and other oxide supports such as SiO2, Al2O3, Zn-Zr, Ce-Zr, and perovskite. Different supports affect the reaction pathway, activity, and selectivity on the catalyst surface, thus influencing the selectivity and yield of methanol. Copper-based catalysts are widely studied and applied, primarily due to their low activity temperature, which is favorable for methanol production equilibrium and allows operation at lower pressures. However, their low methanol selectivity and poor stability are fatal drawbacks, hindering large-scale industrial development. There are two main reasons for this: firstly, the existence of endothermic competing reactions (RWGS). The hydrogenation of carbon dioxide to methanol is an exothermic reaction. According to Le Chatelier's principle, the reaction proceeds in an exothermic direction at low temperatures, favoring methanol production. However, kinetically, carbon monoxide is more easily activated than carbon dioxide at low temperatures. Therefore, increasing the temperature inevitably increases the selectivity of the byproduct carbon monoxide. Secondly, higher metal loadings often lead to the formation of larger copper particles, which frequently sinter under the influence of the reaction atmosphere and water. This easily induces the agglomeration and growth of copper particles at the active sites, resulting in a sharp reduction in effective active sites and a drastic decrease in catalyst stability. Therefore, developing a highly selective and stable copper-based catalyst is of great significance for the long-term development of the carbon dioxide hydrogenation to methanol process.

[0004] Wang WW (Journal of Energy Chemistry, 2020, 40, 22-30) et al. prepared Cu / ZrO2 and Cu / CeO2 via oxalate co-precipitation-deposition precipitation method for the synthesis of methanol from CO2 hydrogenation. Their study found that the interaction between Cu and the support improved the catalytic effect. The reaction was conducted at a pressure of 3.0 MPa, a temperature of 553 K, an H2 / CO2 ratio of 3, and a space velocity of 10000 h⁻¹. -1 Under these conditions, the CO2 conversion rates for Cu / ZrO2 and Cu / CeO2 were 12.4% and 10.1%, respectively, and the selectivity for methanol reached 81.1% and 89.0%.

[0005] Erwin Lam (Chinese Journal of Catalysis, 2019, 40, 11, 1741-1748) et al. studied the performance of mixed oxide-based catalyst Cu / ZrO2 / SiO2 in the selective hydrogenation of CO2 to methanol, and found that the Zr(IV) Lewis acid surface site played an important role in driving the selective generation of methanol. Under the conditions of T = 503 K, P = 2.3 MPa, CO2:H2:N2= 1:3:1, and a gas flow rate of 50 mL / min, the CO2 conversion rate reached 20%, and the methanol selectivity was 78%.

[0006] Yan Xiaofeng (Chemical Industry Progress, 2020, 39(10):4032-4040) et al. prepared a series of Cu-ZnO-ZrO2 catalysts by the sol-gel method. By adjusting the amount of citric acid, the coordination mode of Cu 2+ , Zn 2+ , Zr 4+ and carboxylic acid was controlled, and the crystal grain sizes of the active components CuO, ZnO, and ZrO2 in the catalyst were matched. Under the conditions of a citric acid molar amount of 1.5, a reaction temperature of 523 K, a reaction pressure of 3.0 MPa, H2 / CO2=3, and a gas flow rate of 100 mL / min, the CO2 conversion rate was 27.64%, and the methanol selectivity was 31.76%.

[0007] Fujimoto (Catalysis Communications, 2014, 54, 50-54) et al. studied the effect of different rare earth elements (La, Ce, Nd, and Pr) on the Cu / Zn / Zr (CZZ) catalyst for the synthesis of CH3OH from CO2 hydrogenation. The experimental results showed that the CO2 conversion rate was related to different metal additives. When a small amount of Ce was introduced, the CO2 conversion rate was higher than 20% at T = 483 K, P = 3 MPa, H2 / CO2=3, and W / F = 10 g cat ·h / mol, and the methanol selectivity remained at 50%.

[0008] Peng Gao (Journal of Catalysis, 2013, 298, 51-60) et al. studied the effect of Zr on the performance of Cu / Zn / Al / Zr catalysts for the synthesis of methanol from CO2 hydrogenation. The results showed that the incorporation of an appropriate amount of Zr was beneficial to the generation of methanol, and the catalytic performance was best. When the atomic ratio of Zr 4+ :(Al 3+ +Zr 4+ ) was 0.3, T = 543 K, P = 5.0 Mpa, H2 / CO2=3, and the space velocity was 4000 h -1The CO2 conversion rate is 26.6%, and the methanol selectivity reaches 56.9%.

[0009] The above studies show that the Cu-based catalysts obtained by the conventional synthesis method generally have the disadvantages of high reaction temperature and low methanol product yield. SUMMARY

[0010] The application aims to provide a preparation method of a CuZnZr catalyst containing a defined active site and the application of the catalyst in the low-temperature carbon dioxide hydrogenation to prepare methanol and other derivatives, so as to reduce the reaction temperature, improve the methanol selectivity and the stability of the catalyst, and provide a feasible scheme for the determination of the active site of the catalyst.

[0011] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0012] The reduction of the active copper species to the monatomic dispersion level first forms a Cu1-ZrO2 monatomic catalyst methanol active site on the surface of the catalyst. Since the monodisperse Cu1-ZrO2 monatomic catalyst has a low conversion rate and has 100% specific activity for methanol, through the different metal support interaction degrees of the metal Cu and the amorphous ZrO2, ZnO and ZnZrOx solid solution and other metal oxides, the Cu 0 -ZnZrOx catalyst, Cu 0 -ZnO catalyst and Cu 0 @ZnO catalyst and other catalysts with a defined active site. Secondly, the highly dispersed copper species and the copper species with different particle sizes are in close contact with the metal oxide support. Due to the different metal support interaction degrees, a large number of surface active sites are formed on the catalyst, which improves the stability of the catalyst and significantly improves the CO2 conversion rate. At the same time, the low-temperature condition (180℃) further promotes the generation of methanol in thermodynamics, and avoids the further evolution of the active copper species on the surface of the catalyst.

[0013] The application relates to a preparation method of a CuZnZr catalyst containing a defined active site, and the method is a modified coprecipitation synthesis method. The specific innovation is that the slow precipitation of the metal precursors makes the elements uniformly dispersed, and the different interaction degrees between different metals / oxides make the Cu and other metal oxides form a catalyst with a defined active site.

[0014] Further, the Cu in the catalyst forms a Cu1-ZrO2 monatomic catalyst in a monodisperse state with the amorphous ZrO2, the Cu is anchored by the ZnZrOx solid solution to form a Cu 0 -ZnZrOx catalyst, and the Cu is anchored by the ZnO to form a Cu 0- ZnO catalyst, and Cu is wrapped by ZnOx chemical coating layer to form Cu 0 @ZnO catalyst, the main reason for the formation of different active sites is that the interaction degree of Cu species and metal oxides (amorphous ZrO2, ZnO and ZnZrOx solid solution) is different.

[0015] Further, the CuZnZr catalyst has excellent catalytic performance for low-temperature carbon dioxide hydrogenation to methanol, and the specific performance is that the CuZnZr catalyst (the corresponding percentage content is 15-10-75) has a methanol selectivity of 94.13% at low temperature (180℃), the carbon dioxide conversion rate is 9.89%, and no obvious catalyst deactivation is found in the catalytic life test for 100h.

[0016] Further, the present application provides a CuZnZr catalyst containing a clearly defined active site, and the mass percentage content of Cu, Zr and Zn is as follows:

[0017] Cu: 0.5~31%,

[0018] Zr: 0.1~95%,

[0019] Zn: 0.1~95%.

[0020] The present application provides a preparation method of a CuZnZr catalyst containing a clearly defined active site, comprising the following steps:

[0021] (1) According to the conditions of Cu / Zr molar ratio of 0.01~0.4, Zn / Zr molar ratio of 0.01~0.6, and total metal ion concentration of 0.4~0.8M in the metal precursor solution, the corresponding amount of soluble nitrate salt is weighed and dissolved in 160~300mL deionized water to form a clear transparent solution, which is recorded as solution A. An appropriate amount of anhydrous sodium carbonate is weighed in 160~300mL deionized water, stirred to form a clear solution, and prepared into a 0.6~1.4M solution, which is recorded as solution B. 160~300mL deionized water is weighed in a beaker, stirred and heated to 50~90℃, and recorded as solution C.

[0022] (2) Under the condition of precipitation temperature of 50~90℃, solution A and solution B are simultaneously added to solution C at a rate of 0.2~0.8mL / min by peristaltic pump. After the addition is completed, continue to stir at the precipitation temperature for 0.5~1h, then stop stirring and age at the precipitation temperature for 2~6h.

[0023] (3) The obtained precipitate is washed with deionized water at the same temperature as the precipitation temperature until neutral, and filtered. Then, it is dried at the precipitation temperature for 12-40h, and calcined at 300-500℃ for 4-10h, and then granulated into a 40-60 mesh catalyst for standby use.

[0024] The catalyst of the present application is applied as follows:

[0025] The CuZnZr catalyst sample is pretreated with H2 (100%) as the pretreatment gas, the gas flow rate is 30-50mL / min, the treatment pressure is 1-2bar, the treatment time is 10-20h, and the treatment temperature is 230-300℃. The pretreated CuZnZr catalyst sample is reacted with a mixed gas with a H2 / CO2 molar ratio of 3 / 1, the reaction pressure is 3-5MPa, the reaction temperature is 160-200℃, and the reaction gas flow rate is 10-50mL / min.

[0026] The beneficial effects of the present application are:

[0027] (1) The catalyst surface contains rich Cu1-ZrO2 monatomic catalyst, Cu 0 -ZnZrOx catalyst, Cu 0 -ZnO catalyst and Cu 0 @ZnO catalyst and other well-defined active sites, which have high selectivity (100%) to methanol;

[0028] (2) The low-temperature methanol synthesis can effectively inhibit the generation of carbon monoxide;

[0029] (3) The reaction stability of the catalyst is significantly improved, and no obvious deactivation phenomenon is observed after 100h. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The transmission electron picture, high-magnification transmission electron micrograph and corresponding element mapping graph of the fresh catalyst.

[0031] Figure 2 The transmission electron picture, high-magnification transmission electron micrograph and corresponding element mapping graph of the used catalyst.

[0032] By Figure 1 and Figure 2 We found that the catalyst surface in the catalytic reaction formed rich Cu1-ZrO2 monatomic catalyst, Cu 0 -ZnZrOx catalyst, Cu 0 -ZnO catalyst and Cu 0 @ZnO catalyst and other well-defined active sites. DETAILED DESCRIPTION

[0033] In order to make the content of the present application more convenient to understand, the technical solutions of the present application are further described below in combination with specific embodiments, but the present application is not limited thereto.

[0034] Example 1

[0035] 0.200 g of Cu(NO3)2·3H2O, 0.193 g of Zn(NO3)2·6H2O and 18.089 g of Zr(NO3)4·5H2O were weighed and dissolved in 100 mL of deionized water to prepare a 0.3M clear solution of metal precursor ions (labeled as solution ①). 7.012 g of anhydrous Na2CO3 was dissolved in 100 mL of deionized water to prepare a 0.6M clear solution (labeled as solution ②). 100 mL of deionized water was weighed and heated to 60℃ (labeled as solution ③). Under the reaction condition of 60℃, solutions ① and ② were simultaneously added to solution ③ at a rate of 0.2 mL / min by using a peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60℃ for 3h, and washed with 3000 mL of deionized water until neutral. After suction filtration, the precipitate was dried at 80℃ for 12h. Then, CZZ(1-1-98) containing Cu: 1wt%, ZnO: 1wt% and ZrO2: 98wt% was obtained by calcining at 350℃ for 6h. Finally, it was granulated into 40-60 mesh for use.

[0036] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalyst evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the pretreatment temperature was 250℃ under normal pressure. The CZZ(1-1-98) was purged for 10h. After the pretreatment was completed, the catalyst reaction stage was entered, and the gas was switched to the reaction gas with a CO2 / H2 molar ratio of 1 / 3. The reaction pressure was 3.5 MPa, the reaction temperature was 180℃, and the reaction gas flow rate was 15 mL / min. Under the above conditions, the CO2 conversion rate was 2.48%, the CH3OH selectivity was 100%, no CO by-product was generated, and the CH3OH yield was 2.48%.

[0037] Example 2

[0038] 0.200 g Cu(NO3)2·3H2O, 0.968 g Zn(NO3)2·6H2O, 17.351 g Zr(NO3)4·5H2O were dissolved in 100 mL deionized water to prepare a 0.3 M clear solution of metal precursor ions (labeled as solution ①). 7.012 g anhydrous Na2CO3 was dissolved in 100 mL deionized water to prepare a 0.6 M clear solution (labeled as solution ②). 100 mL deionized water was heated to 60°C (labeled as solution ③). Under the reaction condition of 60°C, solutions ① and ② were simultaneously added to solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60°C for 3 h, and washed with 3000 mL deionized water until neutral. After suction filtration, the precipitate was dried at 80°C for 12 h. Then it was calcined at 350°C for 6 h to obtain CZZ(1-5-94) containing Cu: 1 wt%; ZnO: 5 wt%; ZrO2: 94 wt%. Finally, it was granulated into 40-60 mesh for use.

[0039] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the pretreatment temperature was 250°C under normal pressure. The CZZ(1-5-94) was blown for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the gas was switched to a reaction gas with a CO2 / H2 molar ratio of 1 / 3. The reaction pressure was 3.5 MPa, the reaction temperature was 180°C, and the reaction gas flow rate was 15 mL / min. Under these conditions, the CO2 conversion was 2.01%, the CH3OH selectivity was 100%, and the CH3OH yield was 2.01%.

[0040] Example 3

[0041] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 0.200 g Cu(NO3)2·3H2O, 1.936 g Zn(NO3)2·6H2O, 16.428 g Zr(NO3)4·5H2O in 100 mL deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g anhydrous Na2CO3 in 100 mL deionized water. 100 mL deionized water was heated to 60 °C (labeled as solution ③). Under the reaction condition of 60 °C, solutions ① and ② were simultaneously added into solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. The precipitate was then aged at 60 °C for 3 h and washed with 3000 mL deionized water until neutral. The precipitate was suction filtered and dried at 80 °C for 12 h. Then the CZZ(1-10-89) with Cu: 1 wt%, ZnO: 10 wt%, ZrO2: 89 wt% was obtained by calcining at 350 °C for 6 h. Finally, it was granulated into 40-60 mesh for use.

[0042] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(1-10-89) was pretreated at 250 °C under normal pressure for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the gas was switched to a reaction gas with a CO2 / H2 molar ratio of 1 / 3. The catalyst performance evaluation was carried out under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180 °C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion was 1.60%, the CH3OH selectivity was 100%, and the CH3OH yield was 1.60%.

[0043] Example 4

[0044] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 0.200 g Cu(NO3)2·3H2O, 3.873 g Zn(NO3)2·6H2O, 14.582 g Zr(NO3)4·5H2O in 100 mL deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g anhydrous Na2CO3 in 100 mL deionized water. 100 mL deionized water was heated to 60 °C (labeled as solution ③). Under the reaction condition of 60 °C, solutions ① and ② were simultaneously added into solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. The precipitate was then aged at 60 °C for 3 h and washed with 3000 mL deionized water until neutral. The precipitate was suction filtered and dried at 80 °C for 12 h. Then the CZZ(1-20-79) with Cu: 1 wt%, ZnO: 20 wt%, ZrO2: 79 wt% was obtained by calcining at 350 °C for 6 h. Finally, it was granulated into 40-60 mesh for use.

[0045] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the pretreatment temperature was 250 °C at atmospheric pressure. The CZZ(1-20-79) was purged for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the reaction gas was switched to CO2 / H2 with a molar ratio of 1 / 3. The reaction pressure was 3.5 MPa, the reaction temperature was 180 °C, and the reaction gas flow rate was 15 mL / min. Under these conditions, the CO2 conversion was 1.46%, the CH3OH selectivity was 100%, and the CH3OH yield was 1.46%.

[0046] Example 5

[0047] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 1.000 g Cu(NO3)2·3H2O, 0.968 g Zn(NO3)2·6H2O, and 16.613 g Zr(NO3)4·5H2O in 100 mL of deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g of anhydrous Na2CO3 in 100 mL of deionized water. 100 mL of deionized water was heated to 60 °C (labeled as solution ③). Under the reaction condition of 60 °C, solutions ① and ② were simultaneously added to solution ③ at a rate of 0.2 mL / min by using a peristaltic pump, and the stirring was stopped after the precipitation was completed. The precipitate was then aged at 60 °C for 3 h and washed with 3000 mL of deionized water until it was neutral. The precipitate was suction filtered and dried at 80 °C for 12 h. Then, the CZZ(5-5-90) with Cu: 5 wt%, ZnO: 5 wt%, and ZrO2: 90 wt% was obtained by calcining at 350 °C for 6 h. Finally, it was granulated to 40-60 mesh for use.

[0048] The catalyst evaluation was performed on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(5-5-90) was pretreated at 250 °C under normal pressure for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the reaction gas was switched to CO2 / H2 with a molar ratio of 1 / 3. The catalyst performance evaluation was performed under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180 °C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion rate was 4.08%, the CH3OH selectivity was 99.1%, and the CH3OH yield was 4.04%.

[0049] Example 6

[0050] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 1.000 g Cu(NO3)2·3H2O, 1.936 g Zn(NO3)2·6H2O, 15.690 g Zr(NO3)4·5H2O in 100 mL deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g anhydrous Na2CO3 in 100 mL deionized water. 100 mL deionized water was heated to 60°C (labeled as solution ③). Under the reaction condition of 60°C, solutions ① and ② were simultaneously added into solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60°C for 3 h, and washed with 3000 mL deionized water until neutral. The precipitate was suction filtered and dried at 80°C for 12 h. Then the CZZ(5-10-85) with Cu: 5 wt%, ZnO: 10 wt%, ZrO2: 85 wt% was obtained by calcining at 350°C for 6 h. Finally, it was granulated into 40-60 mesh for use.

[0051] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(5-10-85) was pretreated at 250°C under normal pressure for 5 h. After the pretreatment, the catalyst reaction stage was entered, and the reaction gas was switched to CO2 / H2 with a molar ratio of 1 / 3. The catalyst performance evaluation was carried out under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180°C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion rate was 5.31%, the CH3OH selectivity was 98.7%, and the CH3OH yield was 5.24%.

[0052] Example 7

[0053] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 1.000 g Cu(NO3)2·3H2O, 9.682 g Zn(NO3)2·6H2O, 8.306 g Zr(NO3)4·5H2O in 100 mL deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g anhydrous Na2CO3 in 100 mL deionized water. 100 mL deionized water was heated to 60 °C (labeled as solution ③). Under the reaction condition of 60 °C, solutions ① and ② were simultaneously added into solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60 °C for 3 h, and washed with 3000 mL deionized water until neutral. The precipitate was suction filtered and dried at 80 °C for 12 h. Then the CZZ(5-85-10) with Cu: 5 wt%, ZnO: 85 wt%, ZrO2: 10 wt% was obtained by calcining at 350 °C for 6 h. Finally, it was granulated into 40-60 mesh for use.

[0054] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the pretreatment temperature was 250 °C at atmospheric pressure. The CZZ(5-85-10) was purged for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the reaction gas was switched to CO2 / H2 with a molar ratio of 1 / 3. The catalyst performance evaluation was carried out under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180 °C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion was 4.21%, the CH3OH selectivity was 98.2%, and the CH3OH yield was 4.13%.

[0055] Example 8

[0056] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 3.000 g Cu(NO3)2·3H2O, 0.968 g Zn(NO3)2·6H2O, and 14.767 g Zr(NO3)4·5H2O in 100 mL of deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g of anhydrous Na2CO3 in 100 mL of deionized water. 100 mL of deionized water was heated to 60 °C (labeled as solution ③). Under the reaction condition of 60 °C, solutions ① and ② were simultaneously added to solution ③ at a rate of 0.2 mL / min by using a peristaltic pump, and the stirring was stopped after the precipitation was completed. The precipitate was then aged at 60 °C for 3 h and washed with 3000 mL of deionized water until it was neutral. The precipitate was suction filtered and dried at 80 °C for 12 h. Then, the CZZ(15-5-80) with Cu: 15 wt%, ZnO: 5 wt%, and ZrO2: 80 wt% was obtained by calcining at 350 °C for 6 h. Finally, it was granulated to 40-60 mesh for use.

[0057] The catalyst evaluation was performed on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(15-5-80) was pretreated at 250 °C under normal pressure for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the gas was switched to a reaction gas with a CO2 / H2 molar ratio of 1 / 3. The catalyst performance evaluation was performed under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180 °C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion rate was 9.13%, the CH3OH selectivity was 96.33%, and the CH3OH yield was 8.79%.

[0058] Example 9

[0059] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 3.000 g Cu(NO3)2·3H2O, 1.936 g Zn(NO3)2·6H2O, 13.844 g Zr(NO3)4·5H2O in 100 mL deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g anhydrous Na2CO3 in 100 mL deionized water. 100 mL deionized water was heated to 60°C (labeled as solution ③). Under the reaction condition of 60°C, solutions ① and ② were simultaneously added into solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60°C for 3 h, and washed with 3000 mL deionized water until neutral. The precipitate was suction filtered and dried at 80°C for 12 h. Then the CZZ(15-10-75) with Cu: 15 wt%, ZnO: 10 wt%, ZrO2: 75 wt% was obtained by calcining at 350°C for 6 h. Finally, it was granulated into 40-60 mesh for use.

[0060] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(15-10-75) was pretreated at 250°C under normal pressure for 10 h. After the pretreatment, the catalyst reaction stage was entered, and the reaction gas was switched to CO2 / H2 with a molar ratio of 1 / 3. The catalyst performance evaluation was carried out under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180°C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion rate was 9.89%, the CH3OH selectivity was 94.13%, and the CH3OH yield was 9.30%.

[0061] Example 10

[0062] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 3.000 g Cu(NO3)2·3H2O, 9.682 g Zn(NO3)2·6H2O, 6.461 g Zr(NO3)4·5H2O in 100 mL deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g anhydrous Na2CO3 in 100 mL deionized water. 100 mL deionized water was heated to 60°C (labeled as solution ③). Under the reaction condition of 60°C, solutions ① and ② were simultaneously added into solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60°C for 3 h, and washed with 3000 mL deionized water until neutral. The precipitate was suction filtered and dried at 80°C for 12 h. Then the CZZ(15-50-35) with Cu: 15 wt%, ZnO: 50 wt%, ZrO2: 35 wt% was obtained by calcining at 350°C for 6 h. Finally, it was granulated into 40-60 mesh for use.

[0063] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(15-50-35) was pretreated at 250°C under normal pressure for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the gas was switched to a reaction gas with a CO2 / H2 molar ratio of 1 / 3. The catalyst performance evaluation was carried out under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180°C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion was 8.90%, the CH3OH selectivity was 96.13%, and the CH3OH yield was 8.56%.

[0064] Example 11

[0065] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 6.000 g Cu(NO3)2·3H2O, 0.968 g Zn(NO3)2·6H2O, and 11.998 g Zr(NO3)4·5H2O in 100 mL of deionized water. A 0.6 M clear solution (labeled as solution ②) was prepared by dissolving 7.012 g of anhydrous Na2CO3 in 100 mL of deionized water. 100 mL of deionized water was heated to 60°C (labeled as solution ③). Under the reaction condition of 60°C, solutions ① and ② were simultaneously added to solution ③ at a rate of 0.2 mL / min by using a peristaltic pump, and the stirring was stopped after the precipitation was completed. The precipitate was then aged at 60°C for 3 h and washed with 3000 mL of deionized water until neutral. The precipitate was suction filtered and dried at 80°C for 12 h. Then, the CZZ(30-5-65) with Cu: 30 wt%, ZnO: 5 wt%, and ZrO2: 65 wt% was obtained by calcining at 350°C for 6 h. Finally, it was granulated to 40-60 mesh for use.

[0066] The catalyst evaluation was performed on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(30-5-65) was pretreated at 250°C under normal pressure for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the reaction gas was switched to CO2 / H2 with a molar ratio of 1 / 3. The catalyst performance evaluation was performed under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180°C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion rate was 9.32%, the CH3OH selectivity was 91.70%, and the CH3OH yield was 8.55%.

[0067] Example 12

[0068] A 0.3 M clear solution of metal precursor ions (labeled as solution ①) was prepared by dissolving 6.000 g Cu(NO3)2·3H2O, 1.936 g Zn(NO3)2·6H2O, 7.384 g Zr(NO3)4·5H2O in 100 mL deionized water. A 0.6 M clear solution of Na2CO3 (labeled as solution ②) was prepared by dissolving 7.012 g anhydrous Na2CO3 in 100 mL deionized water. 100 mL deionized water was heated to 60 °C (labeled as solution ③). Under the reaction condition of 60 °C, solutions ① and ② were simultaneously added into solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60 °C for 3 h, and washed with 3000 mL deionized water until neutral. The precipitate was suction filtered and dried at 80 °C for 12 h. Then the CZZ(30-10-60) with Cu: 30 wt%, ZnO: 10 wt%, ZrO2: 60 wt% was obtained by calcining at 350 °C for 6 h. Finally, it was granulated into 40-60 mesh for use.

[0069] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(30-10-60) was pretreated at 250 °C under normal pressure for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the reaction gas was switched to CO2 / H2 with a molar ratio of 1 / 3. The catalyst performance evaluation was carried out under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180 °C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion rate was 9.01%, the CH3OH selectivity was 90.37%, and the CH3OH yield was 7.70%.

[0070] Example 13

[0071] 6.000 g Cu(NO3)2·3H2O, 9.682 g Zn(NO3)2·6H2O, 3.691 g Zr(NO3)4·5H2O were dissolved in 100 mL deionized water to prepare a 0.3 M clear solution of metal precursor ions (labeled as solution ①). 7.012 g of anhydrous Na2CO3 was dissolved in 100 mL deionized water to prepare a 0.6 M clear solution (labeled as solution ②). 100 mL of deionized water was heated to 60°C (labeled as solution ③). Under the reaction condition of 60°C, solutions ① and ② were simultaneously added to solution ③ at a rate of 0.2 mL / min by peristaltic pump, and the stirring was stopped after the precipitation was completed. Then the precipitate was aged at 60°C for 3 h, and washed with 3000 mL of deionized water until neutral. After suction filtration, the precipitate was dried at 80°C for 12 h. Then it was calcined at 350°C for 6 h to obtain CZZ(30-50-20) containing Cu: 30 wt%; ZnO: 50 wt%; ZrO2: 20 wt%. Finally, it was granulated into 40-60 mesh for use.

[0072] The catalyst evaluation was carried out on a single-channel high-pressure fixed-bed catalytic evaluation device. After the catalyst was loaded, hydrogen (100%, 40 mL / min) was used as the pretreatment gas, and the CZZ(30-50-20) was pretreated at 250°C under normal pressure for 10 h. After the pretreatment was completed, the catalyst reaction stage was entered, and the gas was switched to a reaction gas with a CO2 / H2 molar ratio of 1 / 3, and the catalyst performance evaluation was carried out under the conditions of a reaction pressure of 3.5 MPa, a reaction temperature of 180°C, and a reaction gas flow rate of 15 mL / min. Under these conditions, the CO2 conversion rate was 8.56%, the CH3OH selectivity was 89.75%, and the CH3OH yield was 7.68%.

[0073] The above description is only the preferred embodiment of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be included in the scope of the present application.

Claims

1. Application of CuZnZr catalyst in methanol production by carbon dioxide hydrogenation, characterized in that, The CuZnZr catalyst is pretreated by blowing 100% H2 at a flow rate of 40 mL / min at normal pressure for 10 h at 250 ℃, and then the pretreated CuZnZr catalyst is reacted with a mixed gas of H2 / CO2 (molar ratio 3 / 1) at a reaction pressure of 3.5 MPa, a reaction temperature of 180 ℃, and a reaction gas flow rate of 15 mL / min; The preparation method of the CuZnZr catalyst comprises the following steps: 3.000 g of Cu(NO3)2·3H2O, 1.936 g of Zn(NO3)2·6H2O and 13.844 g of Zr(NO3)4·5H2O are dissolved in 100 mL of deionized water to prepare a clear metal precursor ion solution, which is denoted as solution ①; 7.012 g of anhydrous Na2CO3 is dissolved in 100 mL of deionized water to prepare a clear solution, which is denoted as solution ②; 100 mL of deionized water is weighed and heated to 60 ℃, which is denoted as solution ③; under the reaction condition of 60 ℃, solution ① and solution ② are simultaneously added to solution ③ at a rate of 0.2 mL / min through a peristaltic pump, stirring is stopped after the precipitation is completed, then the precipitate is aged at 60 ℃ for 3 h, washed with 3000 mL of deionized water until neutral, filtered, dried at 80 ℃ for 12 h, and then calcined at 350 ℃ for 6 h to obtain the CuZnZr catalyst, which is finally granulated into 40-60 meshes and prepared for use.

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