Cobalt Hydroxide/Heteroatom Doped Graphene Composite as Electrocalyst for Oxygen Reduction Reaction

The composite Cobalt hydroxide/ternary nitrogen, phosphorus and sulfur doped graphene (Co(OH)2/NSPGr) as catalyst for oxygen reduction reaction (ORR), was synthesized by hydrothermal method. The catalytic activity for ORR of catalyst samples were studied by rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) in alkaline medium. Compared to Co(OH)2 which shows a poor catalytic activity, Co(OH)2/NSPGr composite exhibits better catalytic performances, including more positive onset potential and higher limiting current density. Moreover, RRDE results indicate that the composite undergoes a 4-electron electrochemical process as well as a low production of hydrogen peroxide % H2O2. The enhanced performances of Co(OH)2/NSPGr composite could be attributed to the effect of heteroatom doping of graphene and also the strong chemical coupling between Co(OH)2 and NSPGr.