Characterization, Degradation, and Reaction Pathways of Indoor Toluene over Visible-light-driven S, Zn Co-doped TiO₂

Sulfur and Zinc co-doped TiO₂ prepared by a sol-gel method to degrade toluene under a fluorescent lamp was investigated. The results indicate that S,Zn co-doped TiO₂ photocatalysts are mainly nano-size with an anatase phase structure. The degradation reactions of toluene were performed under various operation conditions. The results show that the toluene conversion increases with increasing toluene concentration and decreasing relative humidity. Based on the results of activity test, S_0.05Zn0.001/TiO₂ was chosen for further studies. The main oxidation products of toluene photodegradation are CO₂, H₂O, benzyl alcohol, acetone, butadiene and acetic acid. Two possible mechanisms have been developed for photodegradation of toluene in a dry and a humid environment. (paper)