Boosting the photocatalytic activation of molecular oxygen and photodegradation of tetracycline: The role of interfacial synergistic effect of cocatalyst and dopants

Abstract

Utilizing reactive oxygen species (ROS), which are generated by the activation of molecular oxygen (O2) in oxidation reaction, is a promising method for pollutant degradation. However, it is limited by the commonly low efficiency of O2 activation and carrier separation. Herein, as a model system, Ag cocatalyst and Cl doping modified g-C3N4 (Ag/Cl-CN) was constructed to improve the ability of O2 activation. Results showed that Ag/Cl-CN could effectively convert more O2 into ROS than pristine g-C3N4 (CN), and individually decorated CN (Ag-CN and Cl-CN). A series of experiments and DFT calculations revealed that the deposition of Ag could promote charge separation resulting in more charges accumulated around O2 and the introduction of Cl led to a stronger adsorption capacity for O2. Therefore, due to the synergistic effect of Ag cocatalyst and Cl dopant, Ag/Cl-CN generated higher concentrations of O2− and displayed much better activity for photocatalytic degradation of tetracycline (TC) than CN, Ag-CN and Cl-CN.