Efficient catalytic ozonation over Co-ZFO@Mn-CN for oxalic acid degradation: Synergistic effect of oxygen vacancies and HOO-Mn-NX bonds

Abstract

Co-ZFO@Mn-CN with 1O2 and O2•− as main reactive oxygen species was synthesized for catalytic ozonation, which could efficiently degrade organic pollutants. EPR and XPS analysis indicated that lattice doping of Co induced formation of abundant of OVs, which could provide localized electrons for O3 activation with the generation of HO2•/O2•−. 1O2 and H2O2 were produced by the recombination of HO2•/O2•−. DFT calculation demonstrated that H2O2 was deprotonated to generate HOO−, which preferred to form HOO-Mn-NX bonds with Co-ZFO@Mn-CN. Under the attack of O3, HOO-Mn-NX bonds were broken with the generation of HO2• and HO3•/O3•−, not only accelerating 1O2 production for organics degradation but also avoiding Mn(Ⅱ) sites oxidation. Combining advantages of OVs and HOO-Mn-NX, Co-ZFO@Mn-CN achieved 70–100% mineralization for different organic pollutants. Thus, this work provided a simple and efficient way for enhancing the utilization of O3 by the synergistic effect of OVs and HOO-Mn-NX bonds, also improving ROS transformation.