Enhanced photocatalytic activities of commercial P25 TiO2 by trapping holes and transferring electrons for CO2 conversion and 2,4-dichlorophenol degradation

In this work, commercial P25 TiO2 was co-modified with chloride and phosphate anions by a simple impregnation method, and then coupled with carbon quantum dots with a wet-chemical process. It is demonstrated that the photocatalytic activities of P25 TiO2 for CO2 conversion and 2,4-dichlorophenol degradation are improved obviously after co-modifying chloride and phosphate anions and then coupling with carbon dots. It is confirmed that the modified chloride and phosphate anions could effectively trap photogenerated holes, while the coupled carbon dots could facilitate photogenerated electrons transfer based on the steady-state surface photovoltage spectra, I-V curves, the electrochemical impedance spectra and the formed center dot OH amounts, implying that the photogenerated charge separation of P25 TiO2 is greatly enhanced, leading to the obviously-improved activities. This work would help us develop a much feasible route to improve the photocatalytic activities of P25 TiO2. (C) 2017 Elsevier Ltd. All rights reserved.