Rh–CeO2 interaction 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.