Mesoporous Ce-doped ZnO hollow microspheres for oxidation of 1,2-dichlorobenzene
Mesoporous Ce-doped ZnO hollow microspheres were synthesized for the oxidative decomposition of 1,2-dichlorobenzene (o-DCB) as a model compound of polychlorinated aromatic hydrocarbons (PCAHs). The results showed that the molar ratios of Ce/(Ce + Zn) in the hollow microspheres significantly affected their catalytic performances. ZnCe5 hollow microspheres exhibited the best catalytic activity for o-DCB conversion under both dry and humid conditions, which could be attributed to their well-defined hollow structure with a high amount of mesopores, isolated microspheres, enhanced reducibility and high concentration of surface active oxygen through N2 physical adsorption, H2-TPR and XPS analyses. In situ FT-IR showed that o-DCB could be finally converted into CO2 and H2O via the intermediates phenolate and catecholate followed by acetate, formate and maleate, which provided a clear understanding on the catalytic mechanism over ZnCe5. This work proved that Ce-doped ZnO hollow materials could be used as promising catalysts for the deep oxidation of PCAHs.