Lattice oxygen defect mediated Fe-Olatt-Mn active sites enable efficient non-radical PMS activation

Lattice oxygen defects promote efficient oxidant activation • Iron and manganese sites drive singlet oxygen dominated oxidation • Rapid antibiotic degradation achieved in real water matrices • Catalyst shows low metal leaching and good cycling stability • Treated effluents show low ecological risk in seed germination tests Enhancing the activation efficiency of peroxymonosulfate (PMS) to generate reactive oxygen species (ROS) is crucial for boosting Fenton-like reactions. However, simultaneously promoting PMS adsorption, accelerating interfacial electron transfer, and shifting the activation pathway to optimize its activation kinetics still poses a substantial challenge. Herein, we developed a bimetallic catalyst enriched with lattice oxygen defects, denoted as Fe 14 Mn 1 -LOx, for PMS activation toward the remediation of emerging organic contaminants in aquatic environments. Combined experimental and theoretical mechanistic studies reveal that the intrinsic catalytic activity of Fe 14 Mn 1 -LOx originates from the intermetallic lattice oxygen defects (Fe-O latt -Mn). These defects significantly elongate the O O bond of adsorbed PMS and drastically lower its dissociation energy to 5.79 kJ mol −1 . Furthermore, the Fe-O latt -Mn sites increase the electron density near the Fermi level and adopt a bidentate coordination configuration, enabling faster and more efficient electron transfer to the O O bond, thereby promoting the generation of radical and non-radical species, predominantly singlet oxygen ( 1 O 2 ) with a contribution as high as 97.4%. Benefiting from these merits, the Fe 14 Mn 1 -LOx catalyst exhibits an exceptional degradation rate constant of 0.513 min −1 for tetracycline (TC), a representative emerging contaminant. This rate is 3.72 and 24.4 times higher than those of pristine FeOx (0.138 min −1 ) and MnOx (0.021 min −1 ), respectively. Remarkably, complete TC removal (100%) is achieved within just 10 min, outperforming most reported analogous catalysts. This work underscores the critical role of precisely engineering intermetallic lattice oxygen defects to modulate heterogeneous PMS activation, offering an innovative catalyst design strategy for efficient deep purification of emerging contaminants in real water matrices. Download: Download high-res image (263KB) Download: Download full-size image