An IrRu alloy nanocactus on Cu2−xS@IrSy as a highly efficient bifunctional electrocatalyst toward overall water splitting in acidic electrolytes

Development of highly active and durable bifunctional electrocatalysts for overall water splitting is vital for the economical production of H2 as an alternative energy source. Herein, we report the synthesis of Cu2−xS@IrSy@IrRu nanoparticles (CIS@IrRu NPs), which show excellent catalytic performances for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an acidic electrolyte. Benefiting from the optimal composition of IrRu and the stable IrSy shell, the cactus-like IrRu NPs show high electrocatalytic activity and stability. The cactus-like IrRu NPs exhibit optimal HER and OER performances and high stability at a ratio of Ir/Ru 1.00 : 1.07. In overall water splitting, the CIS@Ir48Ru52 NPs achieve a current density of 10 mA cm−2 at a cell voltage of only 1.47 V in 0.1 M HClO4 electrolyte and show negligible degradation after 100 h of continuous operation in the stability test.