SURFACE AND REDUCTION ENERGETICS OF THE CEO2-ZRO2 CATALYSTS

The (110), (111), and (310) surfaces of cubic CeO2-ZrO2 solid solution s have been studied by computer simulation techniques using atomistic models. Surface energies, Ce4+/Ce3+ reduction energies, and penetratio n profiles of oxygen vacancy formation have been calculated. The resul ts of the calculations suggest some possible factors that could explai n the increase in the oxygen storage capacity experimentally observed in these systems relative to pure ceria: surface Ce4+/Ce3+ reduction e nergies are comparable with previously found bulk values; introduction of zirconia into the ceria lattice decreases the Ce4+/Ce3+ reduction energy on the stable (110) and (111) surfaces; oxygen vacancies tend t o segregate to these surfaces.