CO ₂ Hydrogenation Cu / Zn / Zr Modification Of Rare Earth Oxide Catalysts

CO2is a mostly abundant potential raw material in nature, also is a major gases causing greenhouse effect, which leading to global warming. The environmental problem is more and more to attach importance today, how to use CO2hydrogenation to low carbon alcohol is an interesting subject for people. Methanol is an important chemical raw material, is also promising clean fuel, methanol synthesis from CO2hydrogenation is one of the most effective ways of using CO2,is significance in solving the problem of environmental protection and energy.In this paper, a series of Cu/Zn/Zr catalysts were prepared by co-precipitation method, and studied the structure and adsorption-desorption properties of catalysts by means of XRD, BET, H2-TPR, CO2-TPD.Catalytic performance of Cu/Zn/Zr catalysts modified with La, Ce, Pr, Nd, Sm promoters for methanol synthesis from CO2hydrogenation, CO hydrogenation and CO/CO2hydrogenation were carried out in a fixed-bed plug flow reactor. The results showed that the active of the catalysts were increased in CO2hydrogenation and CO hydrogenation reaction when La-Pr-promoters were added and the interaction of the each component were enhanced. The presence of La-, Pr-promoters effectively increased the dispersion of the active component, strength the interaction between Cu and ZrO2, and therefore stabilized the active center of the catalyst, and In favor of adsorbed species occurs overflow between Cu and ZrO2.In the CO/CO2hydrogenation reaction, the conversions of CO and CO2on Cu/Zn/Zr catalyst modified with the rare earth promoters were lower than that on the unmodified Cu/Zn/Zr catalysts, and the CO2conversion is very low.In further experiments, Cu/Zn/Zr catalysts were modified via the addition of different amounts of La and Pr as rare-earth promoter. A series of Cu/Zn/Zr catalysts were prepared by the co-precipitation method and the influences of La and Pr amount on the structure of Cu/Zn/Zr catalyst was investigated by using XRD,H2-TPR and CO2-TPD.The catalytic performances of CO2hydrogenation to methanol over Cu/Zn /Zr catalysts were tested in a fixed-bed plug flow reactor. The results showed that the addition of rare-earth promoter could obviously enhance the surface alkalinity of catalyst, promote dispersion of the active component efficiently and stabilize the active center of the catalyst. Optimum catalytic activity was obtained over Cu/Zn/Zr catalyst with a La content of2%,the conversion of CO2can reach28.64%, selectivity of methanol reach44.95%..Optimum catalytic activity was obtained over Cu/Zn/Zr catalyst with a Pr content of3%,the conversion of CO2can reach29.95%, selectivity of methanol reach45.10%.