Unveiling the Unified Indicator Role of Lattice Distortion in Reactive Species Generation Within Coupled Oxidation Systems

ABSTRACT Spinel oxide‐catalyzed coupling oxidation systems in peroxymonosulfate (PMS) activation show great potential for removing contaminants. However, establishing structure‐activity relationships remains challenging, which hinders the interpretation of intrinsic catalytic mechanisms. Here, a series of modified Fe ₃ O ₄ catalysts were synthesized with atomic‐level cobalt occupation, enabling co‐regulation of radical and nonradical reactive species (RSs) during PMS activation. Interestingly, lattice distortion, shaped by Co doping and heat treatment, dominated the catalytic performance and presented highly positive correlation with the formation concentration of primary RSs (SO ₄ ^•− , ¹ O _2, and Fe ^{IV = O} ) rather than single catalytic sites. Dynamic analysis revealed that d ‐band center exhibits a threshold with Co doping, whereas good correlation can be established with computational distortion. Adjustments to charge distribution and d ‐orbital structure by lattice distortion supported the PMS adsorption energy enhancement and interaction architecture optimization. The distorted Co‐O _V ‐Fe ₃ O ₄ with coupled oxidation systems demonstrated outstanding pollutants removal performance in complex waters while exhibiting little ecotoxicity to aquatic algae. This in‐depth exploration of the intrinsic origins of spinel oxide activity provides new insights for the construction of customized RSs systems.