Regulating 4f‐2p‐3d Orbital Coupling in CeO ₂ via Dual‐Transition Metal Doping for Efficient Peroxymonosulfate Activation

ABSTRACT Peroxymonosulfate‐based advanced oxidation processes (PMS‐AOPs) face persistent kinetic limitations in CeO ₂ catalysts, notably sluggish interfacial electron transfer and inefficient desorption of oxygen‐containing intermediates. Herein, we engineered a dual‐ transition‐metal (Fe/Co)‐doped CeO ₂ catalyst via self‐templating synthesis, establishing a gradient 4f‐2p‐3d orbital coupling unit to optimize electronic structures. Comprehensive characterization revealed that Fe/Co co‐doping induced lattice distortions, elevated Ce (IV) content, narrowed the 3d (Fe/Co)‐2p (O) energy gap, and enhanced interfacial electron transfer at 4f (Ce) sites. The optimized FeCo3‐CeO ₂ exhibited superior PMS activation efficiency, achieving a norfloxacin degradation rate constant ( k _obs ) of 0.2539 min ⁻¹ , outperforming Fe‐CeO ₂ and Co‐CeO ₂ by 25‐fold and 7‐fold, respectively. Mechanistic studies confirmed dual radical/non‐radical pathways, where Ce sites drove ¹ O ₂ generation while Fe/Co sites initiated SO ₄ ^•− formation. DFT calculations demonstrated a significant reduction in PMS‐intermediates desorption energy (14.70→12.49 eV), effectively resolving kinetic bottlenecks. The catalyst demonstrated broad pollutant applicability, robustness across diverse water matrices, and sustained > 99% pollutant removal during 12‐h continuous‐flow operation. This work provides foundational insights for designing of high‐efficiency 4f‐material catalysts via precise regulation 4f‐2p‐3d orbital coupling for water purification.