Control of MnO2 nanocrystal shape from tremella to nanobelt for ehancement of the oxygen reduction reaction activity

Tremella-like δ-MnO2 (T-MnO2), mixed tremella and belt-like α-MnO2 (M-MnO2), and belt-like α-MnO2 (B-MnO2) were prepared hydrothermally, and B-MnO2 produced the highest oxygen reduction reaction (ORR) activity due to the high molar ratio of surface-located Mn(III) to Mn (IV).208