One-step synthesis of N-doped amorphous carbon at relatively low temperature as excellent metal-free electrocatalyst for oxygen reduction

Transition metal is usually required for obtaining N-doped carbon (d(N)-C) catalysts toward oxygen reduction reaction, leading to an intense debate on whether the active sites in d(N)-C correlate to transition metal. Here, we report that metal-free amorphous d(N)-C was synthesized using simple one-step magnetron sputtering at relatively low temperature. The chemical bonding states of N atoms, which play a key role in optimizing the electrocatalytic activity, can be tuned by adjusting deposition temperature. The metal-free d(N)-C with high pyridinic N content exhibits high electrocatalytic activity, and its stability and methanol tolerance are much better than commercial Pt/C catalyst. (C) 2013 Elsevier B.V. All rights reserved.