Graphitic Mesoporous Carbon Loaded with Iron-Nickel Hydroxide for Superior Oxygen Evolution Reactivity

Earth-abundant transition metal oxides and hydroxides have been intensively investigated as promising catalysts for the oxygen evolution reaction (OER). However, the overall OER performance of the transition metal oxides/hydroxides is largely jeopardized by their inherent low electrical conductivity. Mesoporous carbon has been a commonly used as a carrier material for these oxides/hydroxides to promote the electrical conductivity and provide a large specific surface area. However, most of the available mesoporous carbon carriers are amorphous. It has been very challenging to synthesize graphitic mesoporous carbon owing to the extremely high graphitization temperature. In this work, we report a new strategy used to prepare graphitic mesoporous carbon (GMC) by employing Fe metal as the graphitization catalyst. The graphitic carbon was obtained at 1000 °C, at which it retained its mesoporous structure. The conductivity of the obtained GMC was approximately 550 S m(-1) , which was almost ten times higher than that of amorphous carbon. The GMC was further loaded with Fe-Ni hydroxide to fabricate the OER catalyst. The obtained catalyst showed good OER activity with an overpotential of 320 mV at a current density of 10 mA cm(-2) and a low Tafel slope of 57 mV dec(-1) . The synthesized catalyst also possessed excellent stability, with almost no current drop even after 2000 cycles and at a constant voltage for 2 h.