Electron-deficient B-site engineering in CeNiO₃ for efficient PMS activation and tetracycline degradation

The efficiency of peroxymonosulfate (PMS) activation in advanced oxidation processes is often hindered by weak electronic interactions between the active sites and PMS molecules. To address this challenge, this study presents the synthesis of Fe-doped CeNiO₃ (Fe-CNO) using a combined approach of Fe doping and a metal-organic framework (MOF)-derived strategy. The core innovation involves the introduction of Fe to induce electron-deficient B-site engineering, which strategically reconstructs the electronic structure of the original Ni sites, converting them into highly active, electron-deficient centers. Both experimental and theoretical investigations confirm that these modified centers exhibit reduced electron cloud density, thereby significantly strengthening their interaction with PMS. This enhancement facilitates an optimized electron transfer pathway, lowers the activation energy barrier for O-O bond cleavage, and promotes the generation of diverse reactive oxygen species (ROS). Concurrently, the MOF-derived architecture imparts a high specific surface area to Fe-CNO, and the increased density of active sites synergistically accelerates PMS activation. Fe-CNO achieved a TC degradation efficiency exceeding 90% within 60 minutes via PMS activation, nearly three times higher than that of pristine CeNiO₃. Furthermore, it exhibited minimal metal leaching (<0.07 mg L^-1), excellent pH tolerance (pH = 4-12), and strong cycling stability. This work provides an effective approach for designing novel, stable, and environmentally friendly catalysts and offers valuable insights into the use of CeNiO₃-based perovskites in AOPs.