Efficient photocatalytic in-situ Fenton degradation of 2,4-dichlorophenol via anthraquinone-modified carbon nitride for 2e oxygen reduction.

Constructing a photocatalytic in-situ Fenton system (PISFs) is a promising strategy to address the need for continuous hydrogen peroxide (HO) addition and the low efficiency of HO activation for hydroxyl radical generation in the traditional Fenton reaction. In this study, we constructed a photocatalytic in-situ Fenton system using anthraquinone-modified carbon nitride (AQ-CN) for efficient pollutant degradation. The resultant AQ-CN not only enhanced the production of HO but also increased the generation of hydroxyl radical (·OH). Experimental results demonstrated that, the apparent rate constant for the degradation of 2,4-Dichlorophenol (2,4-DCP) by AQ-CN-PISFs was 0.145 min, which is 2.74 times higher than that of CN under visible light. Density functional theory (DFT) calculations indicate that AQ modification promotes electron-hole separation while increasing the adsorption energy of O. Independent gradient model (IGM) analysis based on Hirshfeld Partition revealed that van der Waals interactions between AQ-CN and 2,4-DCP promoted the degradation process. This work provides new ideas to overcome the problems of continuous addition of HO and low utilization of ·OH that exist in conventional Fenton system.