STUDY OF THE RH SO4/ZRO2 SYSTEM BY DIFFUSE-REFLECTANCE IR SPECTROSCOPY AND X-RAY PHOTOELECTRON-SPECTROSCOPY/

Systems on the basis of Rh/ZrO2 and Rh/SO4/ZrO2 are studied by diffuse -reflectance IR spectroscopy using CO as a molecular probe and X-ray p hotoelectron spectroscopy. Strong interaction of rhodium with basic su rface centers is observed for Rh/ZrO2. Modification of the system with SO42- anions leads to stabilization of positively charged metal forms . The mechanism of stabilization may include the direct interaction of rhodium compounds with SO42- groups, and, as a result, a partial posi tive charge is induced on rhodium atoms. The effect of the support mod ification on the state of rhodium decreases with increasing reduction temperature and metal content.