Catalytic soot oxidation by Ag/BaCeO3 having tolerance to so2 poisoning

Abstract

The effect of SO2 and NO on the catalytic oxidation of diesel particulate (soot) was studied over two Ce oxides, CeO2 and BaCeO3. Silver catalysts loaded on both Ce oxides exhibited the high activity, which was accelerated by the pretreatment in a flow of NO/O 2 mixtures. The adsorption species in the form of NO 2/NO3 should play a role of oxidizing agents for soot. However, the pretreatment of Ag/CeO2 in a flow of SO 2/O2 mixtures caused significant deactivation. Strong adsorption of SO2 onto active site at the three-phase boundary between soot, Ag/CeO2 and the gas phase would be a reason for the deactivation. Ag/ BaCeO3 was found to be a catalyst having much improved tolerance to SO2. The tolerance may be explained by the SO2 adsorption site residing apart from the catalytically active oxygen site. ©2009 The Ceramic Society of Japan. All rights reserved.