Photocatalytic oxidation of small molecule hydrocarbons over Pt/TiO2 nanocatalysts

Abstract

Highly active Pt/TiO₂ catalysts were prepared by a simple photo-reduction method and used for catalytic oxidation of alkanes (C₂H₆ and C₃H₈) and alkenes (C₂H₄ and C₃H₆). It was found that significantly improved photo-activity can be reached even by loading a very small amount of Pt (0.2–0.5 wt%). Moreover, the Pt loading resulted in unexpected visible light activity for the oxidation of small molecule hydrocarbons. Further investigation using photoluminescence spectra indicate that the Pt loading helps reduce the charge carrier recombination within the TiO₂ nanoparticles. Electron Paramagnetic Resonance (EPR) spectra reveal both oxygen molecules and lattice oxygen participate in the hydrocarbons' photooxidation. The transfer and reaction mechanisms of charge carriers during the photo-oxidation process are discussed in detail.