Nitrogen and sulfur dual-doped graphene as an efficient metal-free electrocatalysts for oxygen reduction reaction in microbial fuel cell
Developing highly efficient non-precious metal electrocatalysts for oxygen reduction reaction (ORR) is of great importance to achieve high-performance microbial fuel cells (MFCs). In the present work, nitrogen and sulfur dual- doped graphene (N/S-G) was prepared and used as a cathode catalyst for MFCs. The electrocatalytic activity of as-prepared catalysts towards ORR was evaluated by using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The ORR activity of N/S-G was compared to commercial Pt/C in a neutral medium, and this material showed an electron transfer number of 3.75±0.15, suggesting that ORR catalysis proceeded through the favorable four-electron pathway. More importantly, the MFC with N/S-G as a cathode catalyst achieved a maximum power density of 1368 mW m-2, relatively higher than that with Pt/C (1011 mW m-2). These results demonstrated that N/S-G could be a good candidate as electrocatalyst for MFCs.