Here we report on our investigation on photocatalytic oxidation (PCO) of gaseous methanol with WO 3-TiO 2 composite films. WO 3 and WO 3-TiO 2 composite thin films were prepared by drop casting method. PCO of gaseous methanol and hydrogen generation process on platinum loaded WO 3-TiO 2 composite thin films in high vacuum were investigated using a home-made reactor with a six-channel quadrupole mass spectrometer at real-time scale under UVA (300-400 nm) light illumination. In the case of Pt loaded WO 3 thin films, PCO of gaseous methanol proceeds through intermediates viz. formaldehyde, CO and finally to CO 2 and H 2. PCO of gaseous methanol occurs via direct hole transfer over Pt loaded WO 3 thin films. On the other hand, PCO of gaseous methanol over Pt loaded WO 3-TiO 2 composite thin films proceeds with competitive direct and indirect hole transfer reactions. Our real-time analysis of gas phase photocatalysis realized the identification of direct and indirect hole transfer processes and the reaction intermediates thereof.
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