High-sulfur coal-derived nitrogen, sulfur dual-doped carbon as an economical metal-free electrocatalyst for oxygen reduction reaction.

The search for an economical electrocatalyst for oxygen reduction reaction (ORR) is a worldwide issue for fuel cells and metal-air batteries. Herein, we used cheap and available high-sulfur inferior coal as the single precursor to synthesize an N, S dual-doped carbon (NSC) metal-free electrocatalyst for the ORR. The N, S dual-doped carbon (NSC), prepared at 800 °C (NSC800), possessed a large specific surface area of 942 m 2 g -1 , with an amorphous carbon structure and more defects than the others. Furthermore, it contains 1.06 at% N and 2.24 at% S, where N is resolved into pyridinic-N, pyrrolic-N, and graphitic-N. For the electrochemical behavior, NSC800 displayed a good ORR electrocatalytic activity, with the ORR peak potential at -0.245 V ( vs. SCE) and half-wave potential ( E 1/2 ) at -0.28 V ( vs. SCE) in an alkaline solution. This study not only gives an original and facile method to prepare an economical ORR electrocatalyst but also provides a novel clean-use of high-sulfur inferior coal.