Nanodiamond/nitrogen-doped graphene (core/shell) as an effective and stable metal-free electrocatalyst for oxygen reduction reaction

Nitrogen-doped graphene (N-G) covering a nanodiamond (ND) was prepared via the thermal conversion of ND followed by a new post-doping treatment. Compared with conventional N-G, the core-shell structure of ND/N-G weakened the stacking of graphene nanosheets. Meanwhile the prepared ND/N-G showed a high level of electrocatalytic activity for oxygen reduction reaction (ORR) and a high electrochemical stability. No metal impurities are expected to be introduced into the N-G through this treatment. There is strong support for N-doped as an important factor to enhance the ORR electrocatalytic activity of carbon materials. (C) 2015 Elsevier Ltd. All rights reserved.