Activation of peroxymonosulfate via mediated electron transfer mechanism on single-atom Fe catalyst for effective organic pollutants removal

Cheap and abundant Fe based catalysts in advanced oxidation progresses (AOPs) usually exhibit radicals or high-valent Fe species (HV-Fe) dominated activation mechanism. In this contribution, the atomically dispersed Fe on g-C3N4 (SAFe-CN) was fabricated for peroxymonosulfate (PMS) activation to degrade o-phenylphenol (OPP). OPP removal was not impeded by common radical scavengers, indicating the absence of SO4•− and •OH. The involvement of 1O2 and HV–Fe was excluded and the mediated electron transfer was finally identified as the dominated mechanism. Atomically dispersed Fe sites in SAFe-CN were verified as active sites for reacting with OO bond of PMS and ulteriorly electron shuttling in pollutants degradation. A water treatment filter was fabricated using SAFe-CN and it remained 100% of OPP removal after 100 h of operation. These results provide new insights into the mechanism of mediated electron transfer as well as potential application of non-radical dominated process at device level.