Advanced oxygen reduction reaction catalyst based on nitrogen and sulfur co-doped graphene in alkaline medium

Abstract

A novel nitrogen and sulfur co-doped graphene (N–S-G) catalyst for oxygen reduction reaction (ORR) has been prepared by pyrolysing graphite oxide and poly[3-amino-5-mercapto-1,2,4-triazole] composite (PAMTa). The atomic percentage of nitrogen and sulfur for the prepared N–S-G can be adjusted by controlling the pyrolysis temperature. Furthermore, the catalyst pyrolysed at 1000 °C, denoted N–S-G 1000, exhibits the highest catalytic activity for ORR, which displays the highest content of graphitic-N and thiophene-S among all the pyrolysed samples. The electrocatalytic performance of N–S-G 1000 is significantly better than that of PAMTa and reduced graphite oxide composite. Remarkably, the N–S-G 1000 catalyst is comparable with Pt/C in terms of the onset and half-wave potentials, and displays larger kinetic limiting current density and better methanol tolerance and stability than Pt/C for ORR in an alkaline medium.