Efficient catalytic ozonation for ibuprofen through electron-deficient/rich centers over cerium-manganese doped carbon

Abstract

The sluggish Me(n+m)+/Men+ redox cycle greatly restrained the catalytic ozonation performance of metal-based catalysts. To break this bottleneck, we adopted an interfacial oxidation reaction to create electron-deficient/rich centers within carbon skeleton derived from MOF (C-MOF) by utilizing the electronegativity difference between cerium (Ce) and manganese (Mn), and evaluated its catalytic ozonation activity with ibuprofen (IBP) as model pollutant. XPS, H2-TPR, LSV and EPR characterizations as well as DFT calculation demonstrated that there existed electron-deficient Ce sites and electron-rich Mn sites on CeOx/MnOx/C-MOF. Under the co-function of Ce and Mn sites, CeOx/MnOx/C-MOF/O3 process achieved 100% IBP removal in 90 min, which was 3.1 times of sole ozonation process. IBP could be absorbed at the electron-deficient Ce center and directionally donate its electron to the O3 around electron-rich Mn center. Singlet oxygen (1O2) played the major role in IBP degradation. Cl−, HCO3−, NO3− and SO42− demonstrated limited inhibitions on IBP degradation. This work provided a sustainable strategy for breaking the rate-limiting step in the traditional catalytic ozonation.