Kinetics and Mechanism of the Oxidation of Sulfur Dioxide on α-Fe2O3

Article abstract of DOI:10.1021/j150617a007

The catalytic oxidation of SO2 has been investigated on α-Fe2O3 at temperatures from 250 to 400 deg C under various p_SO2 and p_O2 conditions.The oxidation rates have been correlated with 1.5-order kinetics: first order with respect to SO2 and 0.5 order with respect to O2.SO2 appears to be adsorbed essentially on the O lattice of α-Fe2O3 as a molecular species, while O2 adsorbs on an O vacancy as an ionic species.The conductivity data show that SO2 adsorption contributes electrons to the conduction band and the adsorption of O2 withdraws the conduction electrons from an O vacancy.The conductivies indicate that the adsorption process of SO2 is the rate-controlling step.The oxidation mechanism and the dominant defect of α-Fe2O3 are inferred at given temperatures and p_O2's from the agreement between the kinetic data and conductivies.