Enhanced electrocatalytic activity of a hierarchical CeO2 @MnO2 core-shell composite for oxygen reduction reaction

A novel MnO2 nanosheet-coated CeO2 nanosphere (CeO2@MnO2) core-shell composite was successfully prepared by a simple two-step hydrothermal process as efficient catalyst for oxygen reduction reaction (ORR). XRD, XPS, SEM and TEM analysis techniques were sequentially employed to evidence this CeO2 core-MnO2 shell structure. When utilized for ORR catalyst, such hierarchical core-shell structured CeO2@MnO2 composite delivers a superior electrocatalytic activity than that of MnO2 nanoflowers and CeO2 nanospheres, which is in close proximity to that of commercial 20 wt% Pt/C in alkaline solution, and also exhibits an excellent durability. These properties make the composite potential as cathode catalyst for metal-air battery application. In addition, the enhanced mechanism arising from the synergetic effect of the MnO2 and CeO2 was preliminarily discussed.