The compound nano-ZnO modified with Ce was prepared by homogeneous precipitation.IR,XRD and dynamic experiments show that the crystal size of nano-ZnO desulfurizer is decreased after being modified with Ce and its desulfurization activities are improved greatly.When calcined at 270 ℃,Ce distributes evenly on the ZnO particle surface as amorphous state oxides,and the amorphous ZnO·H2O also exists;when the calcining temperature is 570 ℃,the crystal CeO2 separates out and the amorphous structure of zinc oxide disappears,at the same time,the crystal is perfect and its size increases,but the desulfurization activities decrease.The desulfurization product of nano-ZnO modified with Ce was analyzed with XPS.The results show that the adsorption compound of HS,S and ZnS exists on the surface of the desulfurizer.
Nano-ZnO desulfurizer doped with cerium was prepared by homogeneous precipitation. The bulk and surface structures were characterized by TG-DTA, XRD, XPS and TEM. The desulfurizing performance at ambient temperature was studied. The results show that at ambient temperature the desulfurizing activities of nano-Ce-ZnO desulfurizer are closely related to the particle size, the electron density on desulfurizer surface and the quantity of active sites. Compared with nano-ZnO, nano-Ce-ZnO desulfurizer calcined at 270 ℃ showed smaller particle size and higher surface electron density, which favored the adsorption and reaction of H2S, resulting in improved desulfurizing activity at ambient temperature since the quantity of Zn(2-δ)+ became greater by electron gain of zinc ion from cerium ion. The tendency for zinc and cerium to be separated out as individual oxide from Ce-ZnO desulfurizer would increase as the calcination temperature was raised. The enrichment of cerium on the surface of ZnO made decrease the active sites for H2S adsorption, which led to the decrease in desulfurization activity at ambient temperature.
