Cyclohexane photocatalytic oxidation on Pt/TiO2 catalysts

Gas-solid heterogeneous photocatalytic oxidation (PCO) of cyclohexane in humidified air over TiO2 and Pt/TiO2 catalyst was studied. Pt/TiO2 photocatalysts were synthesized by photodeposition method at different Pt loadings (0.5-2 wt.%). The addition of 0.5 wt.% Pt does not significantly modify the TiO2 properties. The increase in Pt loading induces to an aggregation of metallic particles on TiO2 surface. The cyclohexane PCO was performed in a fluidized bed photoreactor at 60 and 100 degrees C. Pure TiO2 was more active than 1 and 2 wt.% Pt/TiO2 samples at 60 degrees C. Nevertheless, the conversion level increases with temperature on Pt/TiO2 photocatalysts. The cyclohexane was mineralized into CO2, water and low amount of CO. A beneficial effect of Pt addition was found, since total CO2 selectivity was obtained. The Pt/TiO2 photocatalysts prepared by photodeposition provide the total cyclohexane PCO without CO production. Photocatalysts deactivation was not observed in any performed test. Evidence of an opportune tuning of temperature is highlighted. (C) 2012 Elsevier B.V. All rights reserved.