Preparation of Mesoporous MnO2 Catalysts with Different Morphologies for Catalytic Ozonation of Organic Compounds

In this work, we have successfully synthesized three kinds of morphological MnO2 (alpha, delta, gamma-MnO2) with mesoporous structures. The performance of catalysts were evaluated by catalytic oxidation of phenol in saline wastewater using ozone as oxidant at room temperature. The catalysts were characterized by XRD, SEM, BET, O-2-TPD/TPO, TGA and XPS, respectively. The results demonstrate that gamma-MnO2 catalyst is the most active catalyst for phenol removal. It is found that the changes of valence of Mn promote the degradation of phenol, and the existence of lattice oxygen (O-latt) facilitates the circulation of Mn in different valence states. Therefore, Mn4+/Mn3+ and O-latt as active components significantly improved the catalytic activity of gamma-MnO2 and have the best stability.