Rh–CeO₂interaction induced by high-temperature reduction. Characterization and catalytic behaviour in transient and continuous conditions

Abstract

The effects of the high-temperature reduction of Rh/CeO2 catalyst on the hydrogenation of CO, CO2, acetone and ethene, and on the hydrogenolysis of ethane, in transient and continuous conditions, have been investigated. The high-temperature reduction (HTR) at 773 K induced a transient Rh–CeO2 interaction in the catalyst which enhances the rate of CO, CO2 and acetone hydrogenation. Temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) show the reduction of Ce4+ to Ce3+ after HTR in the near surface layers. We suggest that the oxygen vacancies on the support (i.e. presence of Ce3+) can interact with the CO moiety promoting its activation.