Electronic structure modulation of g-C3N4 by Hydroxyl-grafting for enhanced photocatalytic peroxymonosulfate Activation: Combined experimental and theoretical analysis

Graphitic carbon nitride(g-C3N4) materials own the characteristics of metal-free, low cost, and flexible surface modification. However, the defect of high photo-generated electron-hole recombination rate greatly limits its photocatalytic performance. In this paper, hydroxyl-grafting g-C3N4 (CN-OH) was prepared by a simple hydrothermal method. Photocatalytic experiments showed that CN-OH exhibited excellent performance and stability in activating peroxymonosulfate (PMS). 1O2 was the main reactive oxygen species in CN-OH/PMS/Vis system. Hydroxyl-grafting realized the modulation of electronic structure, which caused the reduction of photo-generated electron-hole recombination and the promotion of interfacial electron transfer. Combining experiments and theoretical calculations, the mechanism of its photocatalytic PMS activation was put forward from two aspects: the oxidation process at the positive electrostatic potential region and the reduction process at the negative. The findings provided a valuable reference for the development of efficient photocatalysts through a simple surface modification strategy.