Ultra-facile fabrication of oxygen vacancy-laden catalyst for peroxymonosulfate activation to degrade organic pollutant in water: Performance and mechanism

Abstract

Oxygen vacancy (OV) defect engineering is high-profile for catalyst intensification, but remains in bench scale due to high cost and complicacy. Herein, for the scale- and performance-oriented defect engineering, a highly predigested mechanochemical paradigm was firstly conceived to convert spent Fe-based foodstuff deoxidizers (SFD) into mechanochemistry-derived catalysts (MSFD) via temporary grinding process. The physicochemical properties of MSFD were systematically characterized along with justifying dual-channel formation of OVs, which involved the actions of mechanical energy and reductive carbon components. With swift cycle of ≡Fe(II)/≡Fe(III) redox couple assisted by electron-rich OVs, MSFD could efficiently activate peroxymonosulfate (PMS) for contaminant elimination and bacteria inactivation in water. Hybrid mechanisms were further unveiled in which the radicals were predominant for decontamination, while the aqueous high-valent iron-oxo species played the peripheral role. The electron transfer between ≡Fe and PMS was mediated by the bridging OVs via donor-bridge-acceptor pathway, accounting for the absence of surface high-valent iron-oxo species generated through heterolytic O–O bond cleavage and atom transfer. This work furnishes a generalizable pattern for fabricating cost-effective oxygen-defective materials and profound outlooks into radical and nonradical regimes of persulfate activation.