Nitrogen-Doped Hierarchical Mesoporous/Macroporous Carbon (H-C) Prepared from the Combined Silica Templates with Different Size for Oxygen Reduction

Abstract

In this work, by combining a simple two-step graphitization of the impregnated carbon, we have synthesized novel nitrogen-doped hierarchical mesoporous/macroporous carbon (H-C) with high efficient catalytic activity for ORR by mixing two or more kinds of particle size controlled silica template agent. Results of electrochemical characterization, which was performed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) employing a rotating disk electrode (RDE), with emphasis on the activity of the catalyst are presented. The catalytic activity was found to depend strongly on the porous structure. The resulting H-C obtained from the binary nanosilica template (15nm/500nm = 9:1 in mass) exhibits the highest catalytic performance in terms of ORR among the catalysts studied, where the onset potential at 0.2V, half-wave potential at 0.03V and average transferred electron number at 3.50, were achieved in alkaline media.