Controllable fabrication of a nickel–iridium alloy network by galvanic replacement engineering for high-efficiency electrocatalytic water splitting

Abstract

Developing promising and steady-going bifunctional catalysts for the water electrolytic process (including both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER)) is still a significantly important strategic target for green energy application. Herein, a Ni–Ir alloy network electrocatalyst is successfully constructed via a simple and economical galvanic replacement engineering strategy, which presents remarkable electrocatalytic properties for both the HER and the OER. Originating from the advantages of the porous architecture and synergy between Ni and Ir, a prototype device for overall water electrolysis coupled with the optimized Ni–Ir alloy catalyst affords a low voltage of 1.516 V at 10 mA cm⁻² under alkaline conditions, exceeding the commercial Pt/C∥IrO₂ device (1.611 V) and many other benchmark electrolyzers. Moreover, the water splitting device also features an extraordinary durability of 40 h even at 100 mA cm⁻². This research offers a feasible avenue for the controllable fabrication of high-efficiency and robust network-based electrocatalysts via a galvanic replacement engineering strategy.