Study On Modification Of Silica By Carbon Dioxide Hydrogenation To Methanol - Based Catalyst

Along with the economic high-speed development, CO2concentration in the atmosphere is continuous increasing in the last decade, which results in the greenhouse effects. Meanwhile, as an important resources of carbon, CO2will play an very important role on our sustainable society. As is known to all,it is one of the effective ways to recycle carbon dioxide if we can transform it into useful compounds such as methanol. In addition,methanol is a common chemical feedstock for some important chamicals and a poyential alternative energy to fossil fuels.Consequently, the efficient conversion of CO2hydrogenation for methanol synthesis has received increasing attention from the viewpoint of environmental protection and effective utilization of carbon resources in recent years.In this paper, various CuO-ZnO-ZrO2(CZZ) catalysts and CuO-ZnO-Al2O3-ZrO2(CZAZ) catalysts for methanol synthesis from CO2hydrogenation were prepared by co-precipitation method. Small amount of silica was incorporated into CZZ catalyst to produce these modified CZZ catalysts. The effects of silica on physicochemical and catalytic properties were studied by TG-DTG, XRD, BET, H2-TPR, NH3-TPD and CO2-TPD techniques. The catalytic performance for methanol synthesis from CO2hydrogenation was evaluated. The results obtained are mainly as follows.(1) The test results show that the maximum CO2convrsion of’22.78%and methanol yield of46.64%respectively under the reaction conditions of T=250℃,P=3.0MPa and GHSV=3000h-1were obtained over the CZZ/SiO2catalyst. The CZZ catalyst modified with loading6wt.%SiO2exhibits an higher catalytic activity.The properties of catalysts were strongly influenced by the content of SiO2used as promoter. The silica improves the dispersion of CuO and ZnO component and its modified CZZ catalysts exhibits higher specific surface area, which were confirmed to be responsible for excellent performance of the catalysts for methanol synthesis from CO2hydrogenation(2) The effect of calcination temperature on the catalytic performance and properties of CZZ/SiO2catalysts for methanol synthesis from CO2hydrogenation were studied,and the catalyst was characterized by many method s.The results show that calcination temperature can influence the internation of CuO and ZnO. When the calcination temperature increases from500℃to600℃, the crystallinity and grain of CZZ/Si02catalysts obviously increase and its reduction temperature also increases, but its catalytic activity become more lower. Consequently,it make the show different catalytic performance in CO2hydrogenation to produce methanol. In a word,the calcination temperature of500℃is suitable.(3) The test results show that the maximum CO2convrsion of23.11%and methanol yield of39.81%respectively under the reaction conditions of T=250℃,P=3.0MPa and GHSV=3000h-1were obtained over the CZAZ/SiO2catalyst. The CZAZ catalyst modified with loading4wt.%SiO2exhibits an higher catalytic activity. The characterization of CZAZ/SiO2catalysts show that promoter Al2O3promotes the dispersion of CuO.In addition,the test results show that the catalytic properties of CZAZ/SiO2catalysts are related to the dispersion of CuO.