Mesoporous TiO 2-based photocatalysts for UV and visible light gas-phase toluene degradation

Abstract

UV and visible light photocatalytic removal of concentrated toluene (110 ppm) in the gas phase was performed in an annular flow-reactor on mesoporous anatase TiO 2 supported WO 3 photocatalysts. Depending on the template, hexagonal and cubic mesoporous TiO 2 thin layers were obtained by dip-coating of an anatase sol onto slides of soda lime–silica glass, which was then mechanically removed. The coupling of low contents of WO 3 (4 wt.%) with mesoporous anatase TiO 2 led to high photocatalytic efficiency both using UV and visible light activation. The highly positive effect of WO 3 on the toluene removal efficiency was attributed to a one-way and a two-way coupling phenomena depending on the photocatalyst nature and on the activation source. The hypothesis of a confinement effect of the reactants inside the mesoporous structure, based on an increase in their partial pressure on the active sites, was put forward to explain the high photocatalytic performances obtained under UV and visible light activation.