Porous carbon-coated cobalt sulfide nanocomposites derived from metal organic frameworks (MOFs) as an advanced oxygen reduction electrocatalyst

Abstract

Porous carbon-coated CoS_1.097 nanocomposites (PC-CoS_1.097 NCs) were synthesized by a one-step controlled pyrolysis of the zeolitic imidazolate framework ZIF-9 with sulfur powder. The resulting porous composites contained a high level of nanoparticles of CoS_1.097 and exhibited considerable mesoporosity. With remarkable electrocatalytic activity, the nanocomposites provided a four-electron pathway for the oxygen reduction reaction (ORR) in alkaline medium. The advantages of the synthesized composites over commercial Pt/C include a high methanol crossover resistance and superior long-term stability lasting for 10 000 s cycles. The cost-effective, stable and highly active PC-CoS_1.097 NC electrodes have great potential for application in direct methanol fuel cells (DMFCs). This study lays a foundation for the future development of new cost-effective electrocatalysts.