Nonradical Pathway Regulation Through Electronic Structure Modulation for Multifarious Wastewater

Abstract The rapid development of single‐atom catalysts (SACs) advances water cleanup through the regulation of radical and nonradical pathways; however, the restricted electron utilization efficiency of pollutants still impedes the decontamination. Herein, o‐phenanthroline is added to stabilize Fe single atoms over carbon nitride (phen‐Fe‐CN) with electronic structure modulation, conferring Fe‐N ₄ acting as a stabilized active center. The selectivity of singlet oxygen ( ¹ O ₂ ) is enhanced in the Fenton system for tetracycline hydrochloride (TH) removal, while it is tuned to the electron transfer pathway (ETP) for electron‐rich TH and diclofenac (DCF) with PMS addition. As investigated, the introduction of o‐phenanthroline and the formed Fe‐N ₄ centers are beneficial for modulating the pathway into ETP, with kinetics strongly enhanced both for TH and DCF removal as compared to Fe─CN, as well as delighted removal efficiency with a wide pH range from 1 to 13, sustainable environmental adaptability, and maintained stability. Additionally, o‐phenanthroline has been confirmed to intensify charge transfer and raise the deprotonation barrier, thus leading to a preference for PMS to oxidize pollutants via the ETP pathway. A comparison of various systems with the regulation of radical and nonradical pathway is carried out, thus giving a clear understanding of the detailed functional reaction pathway for practical applications.