Reverse Spillover of Hydrogen Adsorbed Species in Dehydrogenation Photocatalysis on Pt/TiO2 Catalysts

Abstract Photocatalytic dehydrogenation of isopropanol at R.T. is performed on a contact associating Pt dehydrogenation catalyst with a photoactive TiO 2 carrier. Both components are required to photodehydrogenate isopropanol under u.v. irradiation. One of the steps of the reaction is the photoinduced lost of hydrogen by isopropanol (which is converted to acetone) adsorbed on TiO 2 . The hydrogen species then migrates towards Pt particles in order to be released (as dihydrogen) into the gas phase. For small density of Pt sites on TiO 2 surface (for a Pt loading smaller than 1.5%) this reverse spillover seems to be the rate determining step. This hypothesis is reinforced by the study of the influence of H 2 O in this migration.