Abstract

Oxygen vacancies (OVs) play crucial role in peroxymonosulfate (PMS) activation, however, the corresponding catalytic mechanism is ambiguous. Herein, we constructed abundant interfacial asymmetric oxygen vacancies (As-OVs) in OVs-ZnO/Co3O4 that displayed remarkable different catalytic behavior from the symmetric oxygen vacancies (S-OVs) in OVs-CoOx. Specifically, the As-OVs achieved ultra-fast contaminants degradation (∼ 1 min) through both radical attack and electron-transfer process (ETP), while S-OVs exhibited sluggish kinetics for both pathways. Experimental and theoretical analyses revealed that PMS was easily adsorbed on the As-OVs to form PMS* , then ETP immediately occurred once OVs-ZnO/Co3O4 encountered with electron-rich bisphenol A. When electron-poor benzoic acid replaced bisphenol A, the peroxide bond was quickly broken to produce radicals due to the largely polarized PMS* on the asymmetric sites. Conversely, the S-OVs cannot realize rapid removal of both targets because the symmetric sites weakened ETP. This work provides atomic-level insights to understand the catalytic behaviors of OVs.

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