Synthesis of a TiO2–Cu2O composite catalyst with enhanced visible light photocatalytic activity for gas-phase toluene
Abstract
In this study, a TiO2–Cu2O composite catalyst with enhanced efficiency for the gas-phase degradation of toluene was synthesized using the glucose solvothermal method. The TiO2–Cu2O composite catalyst exhibited enhanced stability compared to individual materials (TiO2 or Cu2O). Characterization results revealed the formation of a p–n heterojunction between TiO2 and Cu2O; therefore, the toluene degradation rate is promoted. For the degradation experiments with toluene, the TiO2–Cu2O composite exhibited enhanced efficiency (63%) for toluene degradation compared to TiO2 (40%) under simulated visible-light irradiation. Furthermore, the degradation rate of gas-phase toluene (171.6 mg m−3) by TiO2–Cu2O reached 79% compared to Cu2O (55%) under simulated sunlight irradiation. A mechanistic study indicated that the heterojunction improves the catalytic capability. The conduction band of TiO2 is situated below that of Cu2O; thus, the electron–hole transfer between the heterojunction is thermodynamically permitted. The photogenerated electrons can move from Cu2O to TiO2, while holes migrate from the valence band of TiO2 to Cu2O, thereby preventing the recombination of electrons and holes. hence, the photocatalytic activity is improved.