The Laccase‐Like Mechanism in Peroxymonosulfate‐Based Oxidation System for Water Decontamination: Dual‐Substrate Activation

Abstract

Abstract This study demonstrates that direct electron transfer (DET)‐dominated peroxymonosulfate (PMS)‐based advanced oxidation processes (PMS‐AOPs) share a similar oxidation mechanism with laccase, including dual‐substrate activation, DET mechanism, polymerization of organic pollutants, and relatively high redox potential at active site. To verify this point, a detachable catalyst (MnPc/CNT) was used. Neither manganese phthalocyanine (MnPc) nor carbon nanotubes (CNT) could efficiently catalyze PMS to remove phenol (PE), whereas MnPc/CNT achieved complete PE elimination primarily through a DET mechanism. In this process, PE was mainly removed via polymerization. Importantly, galvanic cell experiments and density functional theory calculations showed that MnPc/CNT can simultaneously activate both PE and PMS, whereas MnPc or CNT alone cannot. This dual‐substrate activation phenomenon was seldom reported in PMS‐AOPs. Comparative studies showed that MnPc/CNT, FePc/CNT, and CoPc/CNT exhibited significantly higher PE removal efficiency than NiPc/CNT, CuPc/CNT, and ZnPc/CNT, which correlated with their higher open circuit potentials. Since current catalyst design strategies for PMS‐AOPs remain largely empirical and enzyme is highly efficient catalyst, this laccase‐like mechanism means that the laccase‐mimetic approach will be a promising direction for developing high‐performance catalysts.