Peroxymonosulfate activation by localized electrons of ZnO oxygen vacancies for contaminant degradation

The activation of peroxymonosulfate (PMS) by multivalent transition metal oxides has been widely studied in organic pollutants degradation. Compared with that of valence electrons, the role of localized electrons of transition metal oxides in the activation of PMS has remained elusive. Herein, ZnO, as a typical irreducible oxide, was used as an ideal model to determine the role of the localized electrons of O-vacancies (Vo) in the PMS heterolysis process. Combined experimental and theoretical analysis demonstrated that O-vacancies, serving as the catalytically active sites, provide enough localized electron retransmission to the adsorbed HSO5−, via a single electron transfer reaction resulting in formation of OH− and SO4−. In addition, O-vacancies promote PMS dehydration to form metastable −SO4-O-O-O4S− that rapidly decompose into O2−, which is responsible for the 1O2 production. This work introduces a unique strategy for obtaining electronic-level insights into the role of catalyst defects in promoting efficient PMS activation.