Photothermal and photochemical processes in solar-light-assisted catalytic ozonation of volatile organic compounds

Abstract

Solar-light-assisted catalytic ozonation has the advantages in energy consumption and removal rate for large-scale application in industrial VOC control. However, the complexity of multiple processes, such as photocatalysis, photothermal conversion, thermal catalysis, and ozonation, causes challenge in evaluating the contribution and interaction mechanism of these processes. Herein, PtOx-loaded CeO2 was chosen as a model catalyst to analyze the synergetic mechanism of the photochemical and photothermal processes. The results showed that toluene degradation by photochemical and photothermal processes on PtOx-CeO2 was initiated by O3 decomposition. PtOx loading enhanced the photothermal conversion efficiency of the catalyst without changing its thermocatalytic activity. Electron-O3 transfer rather than electron-O2 transfer at PtOx-CeO2 interface dominated photochemical process. PtOx enhanced hole transfer to H2O, thereby enhancing charge separation. The results provided us detailed information about the interface behavior of charge carriers in catalytic ozonation.