Single-atom Fe on N-doped carbon drives 100% electron transfer process for organic pollutant degradation: Role of...

Single-atom Fe anchored on N-doped carbon supports have shown promising performance in Fenton-like catalytic reactions. However, the structural characteristics of the NC support, particularly its thickness, have rarely been systematically investigated for their role on peroxymonosulfate (PMS) activation. In this study, Single-atom Fe was immobilized on NC nanosheets with precisely controlled thickness (denoted as SAFe@NC_x). It was clearly demonstrated that the thickness of the NC support played a decisive role in modulating the efficiency of PMS activation. In the SAFe@NC_x/PMS systems, carbamazepine (CBZ) could be completely degraded via a 100% electron transfer pathway, exhibiting remarkable resistance to environmental interference and wide adaptability. Through a combination of spectroscopic characterization and electrochemical analysis, it was revealed that tuning the thickness of the NC carrier effectively optimized the degree of graphitization, adjusted the distribution of N species composition, and thereby enhanced the electronic state of Fe sites and surface charge properties. These structural and electronic modifications induced by support thickness significantly enhanced the adsorption affinity of SAFe@NC toward PMS molecules, further substantially improving the overall catalytic performance in PMS activation.