Abstract

• Among the shape-controlled nanostructures of nanocatalysts, nanodendrites (ND) have attracted great interest, because the rich edges and corners atoms resulting from dendrites structure which are conductive for high catalytic activity. In this study, Ir electrocatalysts doped with different amounts of Co were synthesized by an ethylene glycol (EG) reduction method. Ir and IrCo nanocrystals with Ir/Co ratio of 3:1 (IrCo-3:1) showed nanodendrites structure. Among the samples, IrCo-3:1 sample has excellent electrocatalytic activity toward oxygen evolution reaction (OER) in both acid and alkaline conditions with a minimal onset potential (Vs RHE) and a very low Tafelslope than that of IrCo-1:1 and Ir samples. IrCo-3:1 nanodendrites sample also exhibit good stability under both acid and alkaline solution with negligible degradation after 12 h of chronoamperometry test, revealing their excellent stability under OER conditions.