Enhanced peroxymonosulfate activation through visible-light-responsive ultrathin phosphorus–iron-codoped g-C3N4 nanosheets for efficient naproxen degradation

An efficient photocatalyst was constructed via a simple single-stage thermal condensation reaction and applied to photoinduced peroxymonosulfate (PMS) activation for naproxen (NPX) degradation. Batch experiments demonstrated that phosphorus (P)–iron (Fe)-codoped g-C 3 N 4 (PFeCN) exhibited superior catalytic performance compared to previously reported catalysts, achieving 97 % NPX degradation within 20 min and a reaction rate constant approximately tenfold higher than that of pristine g-C 3 N 4 . P Fe codoping increased active site exposure, improved charge carrier separation efficiency, and enhanced light absorption capacity. Specifically, P N sites served as adsorption and activation centers for PMS, while Fe doping alleviated the reduction in specific surface area caused by P doping and further enhanced photoelectrochemical properties. Radical species analysis confirmed superoxide radicals as the dominant reactive species. The degradation pathways and toxicity evolution of NPX were also investigated, providing critical insights for environmental risk assessment. Furthermore, PFeCN maintained robust catalytic performance under various environmental conditions and after multiple cycles, indicating strong application prospects. This study offers key perspectives on the rational design of heteroatom-doped photocatalysts through atomic-level engineering for efficient photoinduced PMS activation.