Dopamine-coated layered Co0.85Se as an efficient bifunctional oxygen electrocatalyst

Abstract

Development of efficient non-precious and abundant electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is one of the key tasks in renewable energy technologies. Transition-metal selenides have been widely studied as promising candidates. Herein, a layer-structured CoSe₂ was used as a precursor, followed by simple one-step dopamine coating. The as-prepared Co_0.85Se@NC showed outstanding performance in both ORR and OER catalysis. The onset potential and half-wave potential of the ORR in 0.1 M KOH solution can reach 0.96 V and 0.85 V, respectively. The OER overpotential corresponding to 10 mA cm⁻² in 1.0 M KOH solution is only 350 mV, which is much smaller than that of RuO₂ (390 mV). Importantly, the catalyst showed good stability, demonstrating that the layered Co_0.85Se@NC has great potential for advanced bifunctional electrocatalysis.