Enhanced non-radical activation of peroxymonosulfate by g-C3N4 modulated N-doped biochar: The role of extrinsic defects and oxygen-containing functional groups

Abstract

In this study, nitrogen-doped carbon-based materials (LC-CN-x) were prepared by one-pot calcination using g-C₃N₄ as nitrogen source, and PMS were activated for degradation of bisphenol AF. It was found that the addition of g-C₃N₄ regulated the defect degree and the configuration of nitrogen and oxygen species, and the total nitrogen content had a positive linear relationship with k up to R² = 0.92. LC-CN-4 (4 is the amount of g-C₃N₄) has the highest degree of heteroatom doping defects and the best catalytic performance (reaction rate constant 0.1729 min⁻¹). Characterization tests (XRD, Raman, XPS, etc.) and density functional theory calculations (DFT) revealed that atomic rearrangement induced extrinsic defects (pyrrole N and pyridine N) and oxygenated functional group (C=O/O−C=O) during the preparation process were more likely to adsorb PMS, which led to the degradation of BPAF through non-radical mechanisms. This study provides fundamental insights into the regulation of extrinsic defects through heteroatom doping, with the aim of improving the catalytic activity of metal-free materials.