Synthesis of Cobalt Sulfide/Sulfur Doped Carbon Nanocomposites with Efficient Catalytic Activity in the Oxygen Evolution Reaction

Cobalt sulfide/sulfur doped carbon composites (Co₉ S₈ /S-C) were synthesized by calcining a rationally designed sulfur-containing cobalt coordination complex in an inert atmosphere. From the detailed transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analyses, the electrocatalytically active Co₉ S₈ nanoparticles were clearly obtained and combined with the thin sulfur doped carbon layers. Electrochemical data showed that Co₉ S₈ /S-C had a good activity and long-term stability in catalyzing oxygen evolution reaction in alkaline electrolyte, even better than the traditional RuO₂ electrocatalyst. The excellent electrocatalytic activity of Co₉ S₈ /S-C was mainly attributed to the synergistic effect between the Co₉ S₈ catalyst which contributed to the oxygen evolution reaction and the sulfur doped carbon layer which facilitated the adsorption of reactants, prevented the Co₉ S₈ particles from aggregating and served as the electrically conductive binder between each component.