Sulfur poisoning of palladium-based catalysts using cerium oxide

The SO2 poisoning phenomenon of supported palladium catalyst using ceria as oxygen storage materials was studied. Their surface states were measured before and after poisoning and examined sulfur desorption behavior. The desorption temperature of the sulfur adsorbed on Pd/CeO2 was higher than that of Pd/Al2O3 in reduced condition, and gave an influence on regeneration. We suggest this was caused by the interaction between reduced palladium and ceria based on reducibility of ceria from an analysis of the sulfur quantity and chemical states change of catalyst. Also we studied the effect of atmosphere on the SO2 poisoning of Pd/CeO2 at the fixed temperature. As a result, at 573 K adsorbed SO2 would interfere the oxygen storage ability of Pd/CeO2 in oxidizing condition and deactivate the surface of palladium in reducing condition.