Mediating peroxymonosulfate activation path in Fenton-like reaction via doping different metal atoms into g-C₃N₅

Peroxymonosulfate (PMS) could be activated by either radical path or non-radical path, how to rationally mediate these two routines was an important unresolved issue. This work has introduced a simple way to address this problem via metal atom doping. It was found that Fe-doped nitrogen-rich graphitic carbon nitride (Fe-C₃N₅) exhibited high activity towards PMS activation for tetracycline degradation, and the degradation rate was 3.14 times higher than that of Co-doped nitrogen-rich graphitic carbon nitride (Co-C₃N₅). Radical trapping experiment revealed the contributions of reactive species over two catalysts were different. Electron paramagnetic resonance analysis further uncovered the non-radical activation path played a dominated role on Fe-C₃N₅ surface, while the radical activation path was the main routine on Co-C₃N₅ surface. Density functional theory calculations, X-ray photoelectron spectroscopy analysis, and electrochemical experiments provided convincing evidence to support these views. This study supplied a novel method to mediate PMS activation path via changing the doped metal atom in g-C₃N₅ skeleton, and it allowed us to better optimize the PMS activation efficiency.