One-step synthesis of S, N dual-element doped rGO as an efficient electrocatalyst for ORR

Abstract

The commercial application of oxygen reduction reaction (ORR) technology challenges the development of new electrocatalysts with excellent performance, high stability and low cost. Non-metallic materials, especially graphene-based catalysts, have become potential electrocatalysts for ORR due to their source richness and good stability. Here, we report a simple one-step hydrothermal method to synthesize S, N dual-element doped reduced graphene oxide (S, N-rGO) for ORR using graphene oxide as carbon source, thiourea as both sulfur-nitrogen source and reducing agent. The ORR performance is effectively enhanced by heteroatoms doping that increases the active sites of edge defects, introduces new S and N active sites, and adjusts the electronic structure of rGO. The 0.05-S, N-rGO catalyst shows the optimal ORR activity under alkaline conditions with the onset potential of 0.793 V vs RHE, good stability and anti-tolerance toward methanol. The calculated electron transfer number of about 3.1 ± 0.1 suggests that both the two-electron and four-electron processes occur on the catalyst.