Diethylenetriamine (DETA)-assisted anchoring of Co₃O₄ nanorods on carbon nanotubes as efficient electrocatalysts for the oxygen evolution reaction

A Co₃O₄ nanorod-multiwalled carbon nanotube hybrid (Co₃O₄@MWCNT) has been fabricated as a highly efficient electrocatalyst for water oxidation in alkaline electrolytes. The well-defined Co₃O₄ nanorods were successfully anchored onto mildly oxidized MWCNTs with the assistance of diethylenetriamine (DETA) following a simple route. The as-prepared hybrid possesses a promising BET specific surface area of about 252 m² g^-1 and shows excellent electrocatalytic activity towards oxygen evolution reactions (OERs) with an onset potential of about 0.47 V vs. Ag/AgCl and an overpotential of 309 mV to achieve a current density of 10 mA cm^-2 in 1.0 mol L^-1 KOH. In addition, the Co₃O₄@MWCNT catalyst exhibits prominent stability during long-term electrolysis of water. We attribute the enhanced performance to a synergic effect between MWCNTs and Co₃O₄ nanorods by gaining insight into the electrochemical properties of the Co₃O₄@MWCNT hybrid. This work offers a useful way to synthesize one-dimensional (1D) metal oxides combined with 1D carbon materials for wide applications in energy storage and conversion.