Impact of Rh-CeOx interaction on CO oxidation mechanisms

We have investigated the impact of electronic metal-support interaction on catalytic properties of Rh/CeOx system, i.e. its capacity for the reverse and direct oxygen spillover, in the context of CO oxidation. The studies were carried out on two types of samples consisting of Rh particles supported on polycrystalline nearly stoichiometric and partially reduced cerium oxide films using temperature programmed reaction, temperature programmed desorption, and conventional X-ray and resonant photoelectron spectroscopies. We have found that the electronic Rh-CeOx interaction leads to a buildup of a net positive charge on Rh particles supported on stoichiometric cerium oxide, and a net negative charge on Rh particles on reduced cerium oxide. The effect of the Rh-CeOx interaction is manifested in suppression of the reverse and direct oxygen spillover on Rh particles supported on partially reduced ceria.