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

•Metal-free amorphous N-doped carbon catalyst for oxygen reduction was synthesized.•Synthetic method was one-step magnetron sputtering at relatively low temperature.•Chemical bonding states of N atoms were tuned by adjusting deposition temperature.•The optimized catalyst exhibited high activity, stability and methanol tolerance.•Pyridinic N in film was confirmed as an active site.

Transition metal is usually required for obtaining N-doped carbon (dN-C) catalysts toward oxygen reduction reaction, leading to an intense debate on whether the active sites in dN-C correlate to transition metal. Here, we report that metal-free amorphous dN-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 dN-C with high pyridinic N content exhibits high electrocatalytic activity, and its stability and methanol tolerance are much better than commercial Pt/C catalyst.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide