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

Abstract

Constructing a photocatalytic in-situ Fenton system (PISFs) is a promising strategy to address the need for continuous hydrogen peroxide (H2O2) addition and the low efficiency of H2O2 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-C3N4) for efficient pollutant degradation. The resultant AQ-C3N4 not only enhanced the production of H2O2 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-C3N4-PISFs was 0.145 min−1, which is 2.74 times higher than that of C3N4 under visible light. Density functional theory (DFT) calculations indicate that AQ modification promotes electron-hole separation while increasing the adsorption energy of O2. Independent gradient model (IGM) analysis based on Hirshfeld Partition revealed that van der Waals interactions between AQ-C3N4 and 2,4-DCP promoted the degradation process. This work provides new ideas to overcome the problems of continuous addition of H2O2 and low utilization of ·OH that exist in conventional Fenton system.