Heterogeneous photocatalytic oxidation of benzene, toluene, cyclohexene and cyclohexane in humidified air: comparison of decomposition behavior on photoirradiated TiO2 catalyst

Gas–solid heterogeneous photocatalytic decomposition of benzene, toluene, cyclohexane and cyclohexene over TiO2 was studied at room temperature, and their reactivities were compared. Catalyst deactivation was ascribed to the formation of the carbon deposits on TiO2 surface, and the formation and decomposition behavior of the carbon deposits affected the decomposition rate. Deactivated TiO2 catalysts were photochemically regenerated in the presence of water vapor, and the carbon deposits were decomposed to COx.