Photocatalytic toluene degradation: braiding physico-chemical and intrinsic kinetic analyses

Abstract

In this study, we analyzed the photocatalytic degradation of toluene using composite systems consisting of a tungsten oxide component supported on a pure anatase phase. To scrutinize the photocatalytic process, herein we presented a new method with combined spectroscopic and kinetic tools to provide novel and quantitative information mostly obtained in situ under reaction conditions. First, it allows us to extract information quantitatively, regarding charge recombination and the fraction of kinetically relevant charge species reaching the surface of the material and used in chemical steps. In addition, the method allows us to detail how efficiently such kinetically relevant charge carrier species interact with key reactant and intermediate molecules. The application of such procedure to the elimination of toluene shows how the composite system improves the activity with respect to the relevant pure-anatase reference catalyst. This appears to be a complex phenomenon, with implication in several elemental steps of the reaction. The new method can be easily generalized to any photocatalytic reaction and would pave the way to progress in the quantitative understanding of the photocatalytic process.