Nanosized CeO2-supported metal oxide catalysts for catalytic reduction of SO2 with CO as a reducing agent

Abstract

Nanosized CeO2 was synthesized by sol–gel method and used as the support to prepare six kinds of supported metal oxide catalysts by incipient wetness impregnation method. These catalysts were investigated for the catalytic reduction of SO2 to elemental sulfur with CO as a reducing agent. Experimental results indicate that Cr2O3/nano-CeO2 was the most active catalyst. Using this catalyst, a kinetic study was performed on the reduction of SO2 and the optimal feed ratio of CO/SO2 was found to be 2.5/1, and low concentrations of SO2 and CO provide a high SO2 conversion and sulfur yield. We also found that the catalyst presulfided by CO + SO2 exhibits a higher performance than those pretreated with CO, SO2 or He. The discrepancy in the stability and activity resulted in the pretreatment has been rationally explained. The temperature-programmed desorption patterns of SO2 and CO illustrate that Cr2O3/nano-CeO2 can adsorb and desorb SO2 and CO more easily than can other catalysts. These results may properly explain why Cr2O3/nano-CeO2 has a higher activity for the reduction of SO2.