LAUSR

A class of non-precious metal Co, N, S tri-doped carbon (Co/NSC) electrocatalyst for oxygen reduction reaction (ORR) is synthesized from earth-abundant high-sulfur inferior raw coal as the single N, S and C precursor by a two-step co-pyrolysis method. High-sulfur raw coal derived N, S co-doped carbon (NSC) and direct co-pyrolysis coal with CoCl2 (coal-Co) are also prepared for comparison. The as-prepared Co/NSC has an amorphous carbon structure and is doped with heteroatoms N, S and Co nanoparticles in the carbon matrix. Furthermore, compared with NSC, S content decreases obviously and N content mainly in the form of pyrrolic-N changes little in Co/NSC. The as-prepared Co/NSC exhibits a more excellent ORR electrocatalytic activity than that of NSC and coal-Co in terms of the onset potential, ORR peak potential, the half-wave potential, the limiting-diffusion current density and the predominantly 4-electron transfer pathway in 0.1 M KOH. Based on these results, some possibilities attributing to the enhanced performance of Co/NSC are also explained. This two-step co-pyrolysis process is also demonstrated a green utilization of high-sulfur raw coal.