Construction of CeO2/TiO2 heterojunctions immobilized on activated carbon fiber and its synergetic effect between adsorption and photodegradation for toluene removal

摘要

Toluene, as one of the most representative volatile organic compounds (VOCs), poses a serious threat to the atmospheric environment and human health. Herein, cerium dioxide (CeO2)/TiO2 immobilized on activated carbon fiber (ACF) is fabricated by ultrasonic-assisted sol-gel impregnation method for toluene removal. Characterizations of CeO2/TiO2/ACF composites reveal that CeO2 disperses or covers the surface of TiO2/ACF, and Ce4+ does not enter the lattice of TiO2 to replace Ti4+. The TEM and UV-vis analysis indicate the formation of heterojunction between TiO2 and CeO2. The Ce4+/Ce3+ redox centers significantly boost the separation efficiency of electron-hole pairs. The maximum removal efficiency of 1.5% CeO2/TiO2/ACF can reach up to 90%, much higher than 54% over TiO2/ACF. The CeO2/TiO2/ACF composites exhibit high removal efficiency of toluene due to the synergetic effects between adsorption and photodegradation. The gas-phase photodegradations are benzene, benzaldehyde, hexane, phenol, O-xylene, and phenylethyl acetate.