Highly efficient degradation of 2,4-dichlorophenol over CeO2/g-C3N4 composites under visible-light irradiation: Detailed reaction pathway and mechanism

Herein, we report for the first time the highly efficient degradation of 2,4-dichlorophenol (2,4-DCP) over CeO2/g-C3N4 composites (xCeO/CN) prepared via wet-chemical solution method. It is shown that the resultant nanocomposites with a proper mass ratio percentage (15%) of CeO coupled exhibit greatly enhanced visible-light activity for 2,4-dichlorophenol (2,4-DCP) degradation compared to the bare g-C3N4. From photoluminescence (PL) and Fluorescence (FL) results, it is suggested that enhanced photo-degradation is attributed to the significantly improved charge separation and transfer as a result of the proper band alignments between g-C3N4 and CeO components. Further, from radical trapping experiments, it is confirmed that hydroxyl radicals (OH) are the predominant oxidants involved in the degradation of 2,4-DCP over CeO/CN composites. Furthermore, a possible reaction pathway and detailed photocatalytic mechanism for 2,4-DCP degradation is proposed mainly based on the detected liquid chromatography tandem mass spectrometry (LC–MS) intermediate products, that readily transform into CO2 and H2O. This work would help researchers to deeply understand the reaction mechanism of 2,4-DCP and would provide feasible routes to fabricate g-C3N4-based highly efficient photocatalysts for environmental remediation.