Surface structure and redox chemistry of ceria-containing automotive catalytic systems

A summary is given of recent work done at the authors' laboratory, using several spectroscopies, molecular modeling and catalytic activity tests, to study the surface reactivity of ceria-containing high surface area solids useful for automotive exhaust depollution catalysis. Issues addressed include the influence of the basicity of the cerium ion ligand environment on its ability for activation of O-2 at the material surface, and its modification by supporting on alumina or doping with Cl- or other anions; the tendency to grouping of oxygen vacancies at the CeO2 (1 1 1) surface, the higher ease for formation of surface reduced centers in mixed (Zr,Ce) oxides; and the effect of electronic transfer and other chemical interactions induced by ceria on the redox reactivity of transition metal-containing catalysts.