Nitrogen doped coal with high electrocatalytic activity for oxygen reduction reaction

Abstract

It is of a great challenge to develop high efficient nonprecious electrocatalysts to replace Pt-based catalysts for oxygen reduction reaction (ORR). This study introduces a cost-effective and environmentally friendly ORR electrocatalyst based on nitrogen doped coal (NOC) via a preoxidization of raw coal followed by a urea assisted annealing process. The obtained materials show great electrocatalytic activity with the onset potential, half-wave potential, and diffusion-limited current density comparable to those of a commercial Pt/C catalyst. In addition, it follows a four-electron pathway and has relatively low peroxide yield. Finally, it exhibits a good stability and strong tolerance to methanol poisoning. A systematic characterizations illustrate that these great performance could arise from high graphitic N and pyridinic N contents, existence of trace metal elements, and porous structures in the synthesized NOC. The demonstrated high performance makes NOC a promising catalyst for applications in metal air batteries and alkaline fuel cells.