Graphene supported atomic Co/nanocrystalline Co3O4 for oxygen evolution reaction

Abstract Electrochemical water splitting by a robust electrocatalyst plays a key role in hydrogen production for clean and sustainable energy. In this work, a kind of nanohybrid of graphene supported atomic Co and nanocrystalline Co 3 O 4 was synthesized through electrochemical synthesis of atomic cobalt onto graphene using 1-Butyl-3-methylimidzolium tetrachlorocobalt [(BMIm) 2 CoCl 4 ] as an electrolyte. By virtue of the synergistic effect of single-cobalt atoms and Co 3 O 4 nanoparticles, the nanohybrid presents enhanced electrocatalytic performance toward the oxygen evolution reaction. The low onset potential is 0.49 V (vs. Ag/AgCl) and the overpotential of the current density of 10 mA cm −2 is 0.30 V in aqueous solution, which is comparable to commercial RuO 2 . Moreover, the nanohybrid exhibits remarkably long stability for over 45 h at a fixed potential of 0.6 V.