REDUCTION OF NO OVER PARTIALLY REDUCED METAL-LOADED CEO2-ZRO2 SOLID-SOLUTIONS

CeO2-ZrO2 solid solutions supported with Rh and Pt are investigated as catalysts for reduction of NO by CO. The incorporation of ZrO2 into t he CeO2 framework strongly promotes the reduction of Ce4+ in the bulk of the support. The effects of the reduction temperature are investiga ted and it is shown that when bulk oxygen vacancies are formed in the reduced CeO2-ZrO2 solid solution, NO is efficiently decomposed on the support to give N2O and N-2. The presence of bulk oxygen vacancies is indicated as the driving force for NO dissociation, suggesting their i ndirect participation in the catalytic cycle. (C) 1996 Academic Press, Inc.