Growth of IrCu nanoislands with rich IrCu/Ir interfaces enables highly efficient overall water splitting in non-acidic electrolytes

Abstract Developing a novel method to construct highly active interfaces is a direct way to promote water splitting. Herein, rich IrCu/Ir interfaces can be successfully built by epitaxial growth of abundant IrCu nanoislands on IrCu nanowires, which can display superior performance for overall water splitting in both basic and neutral conditions. In particular, it only requires 38 and 242 mV to reach the current density of 10 mA cm-2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline medium, respectively. Meanwhile, it can also exhibit much better intrinsic activity than that of Pt/C and IrO2 in neutral solution. Further mechanistic studies reveal that numerous IrCu/Ir interfaces account for the enhanced catalytic activity of water splitting because this unique heterostructures can largely improve the intrinsic activity of OER and HER by boosting the adsorption of intermediates and facilitating the dissociation of water molecules, respectively. In addition, the distinctive one dimensional structure could effectively prevent the aggregation of electrocatalysts and enhance electrons transfer during water splitting. This work paves an original interface-engineering approach to build highly efficient heterostructures for water splitting, which may be extended to the preparation of other metal catalysts.