Selective ozone catalyzation modulated by surface and bulk oxygen vacancies over MnO2 for superior water purification

Abstract

The regulation behavior of oxygen vacancies (Vo) at different spatial positions (surface or bulk) in catalysts for selective O3 catalyzation, along with the reaction pathways evolution was well-investigated in α-MnO2−x/O3 systems. Combined characterization methods, systematic organic removal experiments, structure-activity relationship analysis, and theoretical calculations were employed to unveil O3 decomposition and electron transfer behaviors regulated by surface or bulk Vo. The contribution of electron transfer process (ETP) to atrazine (ATZ) removal was reinforced from 5.2 % to 34.8 % with the formation of bulk Vo, and Vo-rich α-MnO2−x-2/O3 system achieved ∼96.5 % ATZ removal along with improved TOC mineralization (∼38 % vs. ∼20 %). Surface Vo facilitated O3 adsorption, promoting its decomposition into •OH, while bulk Vo not only accelerated •OH production but also withdrew electrons from organics to build ETP. This study shed light on precise modification of metal-based catalysts with Vo to modulate •OH/ETP synergistic processes in catalytic ozonation for efficient water purification.