Ultralow H 2 O 2 ‐Triggered Electron Transfer over Single‐Atom Iron Catalysts for Long‐Term Recyclable Fenton‐Like Reactions

Abstract Excessive consumption of hydrogen peroxide (H 2 O 2 ) in Fenton and Fenton‐like processes highlights the urgent need for catalytic systems that enable efficient pollutant removal with low H 2 O 2 usage. In this study, we design a single‐atom iron/graphene oxide (Fe 1 ‐GO) catalyst with an Fe─O─C configuration that facilitates pollutant removal under visible‐light (VL) irradiation with minimal H 2 O 2 input, while ensuring long‐term catalytic stability. Using only 2 mM H 2 O 2 , the system sustained over 95% removal of carbamazepine (CBZ) across four cycles, exhibiting a high H 2 O 2 utilization efficiency of nearly 100% for CBZ mineralization. In situ experimental analyses and density functional theory (DFT) calculations reveal that H 2 O 2 triggers the formation of Fe(IV)═O on Fe 1 ‐GO, promoting electron transfer from CBZ to Fe(IV)═O. This process drives H 2 O 2 generation via oxygen reduction on Fe atoms, thereby continuously replenishing H 2 O 2 in the system. A large‐scale continuous‐flow reactor incorporating a Fe 1 ‐GO/polyacrylonitrile membrane efficiently removed CBZ over 420 min using only 2 mM H 2 O 2 . Compared to conventional Fenton processes, this system significantly reduces H 2 O 2 and catalyst usage, resulting in a 10‐fold decrease in operating costs. This study provides a sustainable strategy for pollutant removal through low‐H 2 O 2 ‐input, long‐term recyclable Fenton‐like reactions.