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

Co-ZFO@Mn-CN with O-1(2) and O-2(center dot-) 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 center dot/O-2(center dot-). O-1(2) and H2O2 were produced by the recombination of HO2 center dot/O-2(center dot-). DFT calculation demonstrated that H2O2 was deprotonated to generate HOO-, which preferred to form HOO-Mn-N-X bonds with Co-ZFO@Mn-CN. Under the attack of O-3, HOO-Mn-N-X bonds were broken with the generation of HO2 center dot and HO3 center dot/O-3(center dot-), not only accelerating O-1(2) production for organics degradation but also avoiding Mn(II) sites oxidation. Combining advantages of OVs and HOO-Mn-N-X, 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 O-3 by the synergistic effect of OVs and HOO-Mn-N-X bonds, also improving ROS transformation.

Automated summary

In this study, a catalyst Co-ZFO@Mn-CN was synthesized for efficient degradation of organic pollutants through catalytic ozonation, and the synergistic effect of OVs and HOO-Mn-N-X bonds was demonstrated to enhance O-3 utilization and improve ROS transformation.