A graphene-like nanoribbon for efficient bifunctional electrocatalysts

Abstract

Graphene nanoribbons (GNRs) are conducive to full exposure of catalyst sites, which can be used to synthesize highly efficient electrocatalysts. However, the design of stable and efficient GNR catalysts remains a great challenge. Herein, a novel iron and cobalt co-doped carbon-based catalyst (C-MP-FeCo) with a GNR structure has been developed by a facile and one-step heat-treatment method. C-MP-FeCo is an excellent bifunctional electrocatalyst for low potential difference ΔE between the oxygen-evolution reaction and oxygen-reduction reaction (ΔE_C-MP-FeCo = 0.70 V vs. ΔE_(Pt/C+RuO2) = 0.765 V). The maximum power reached 331 mW cm⁻² at 0.97 V for a Zn–air battery derived from the C-MP-FeCo catalyst, and with the Pt/C + RuO₂ catalyst it was only 249 mW cm⁻² at 0.89 V; also, better discharge performance, voltage efficiency and durability were delivered by the former catalyst. Our findings show that the main methods of increasing electrocatalytic activity are (1) forming GNRs and exposing active sites, and (2) exploiting the synergistic effects of Fe, Co, N, and F.