New insights into the effect of morphology on catalytic properties of MnO x -CeO 2 mixed oxides for chlorobenzene degradation.

We synthesized four CeO 2 -MnO x mixed oxides with different morphologies using simple hydrothermal methods. The catalytic activity for chlorobenzene (CB) degradation decreases in the following order: rod-CeO 2 -MnO x > plate-CeO 2 -MnO x > polyhedra-CeO 2 -MnO x > cube-CeO 2 -MnO x . CeO 2 and MnO x in the mixed oxides are highly dispersed and two new phases of both todorokite (S.G.: P 2/ m : b ) and vernadite (S.G.: I 4/ m ) with a special tunnel-like structure are found. Both rod-CeO 2 -MnO x and plate-CeO 2 -MnO x exhibit increased lattice microstrains generated from lattice distortion and defects; further, there are more oxygen vacancies and more MnO x (Mn 4+ and Mn 2+ ) species on the surface, particularly when compared to cube-CeO 2 -MnO x . Therefore, this promotes deeper oxidation activity for CB. Moreover, the strong interaction between CeO 2 and MnO x also promotes the redox ability of CeO 2 -MnO x mixed oxides, while their oxygen storage capacity (OSC) properties are not only intrinsic to their structures but also limited to their surfaces and by their particle sizes.