Sensitivity of CO oxidation toward metal oxidation state in ceria-supported catalysts: an operando DRIFTS-MS study

SSCI-VIDE+ECI2D+LPIInternational audienceThe oxidation of carbon monoxide has been studied on pristine CeO2, Rh-CeO2, and Pt-CeO2 powders prepared in one step by solution combustionsynthesis (SCS). The reaction was cycled between an oxygenrich and aCO-rich feed with regard to the stoichiometric conditions. CO2production was monitored by mass spectrometry, while the surface specieswere probed by operando DRIFTS (Diffuse Reflectance Infrared FourierTransform Spectroscopy). Whereas the reaction starts above 150 degrees Con CeO2 and Rh-CeO2 and does not depend on the state of the surface(oxidized or reduced), the reaction on Pt-CeO2 shows strong dependencyon the initial state and substantial activity is achieved at much lowertemperatures with the CO-rich feed. We relate this result to the changein the oxidation state of Pt via strong interaction with ceria