Abstract

Abstract A binder‐free efficient MoNi 4 /MoO 3‐ x nanorod array electrode with 3D open structure is developed by using Ni foam as both scaffold and Ni source to form NiMoO 4 precursor, followed by subsequent annealing in a reduction atmosphere. It is discovered that the self‐templated conversion of NiMoO 4 into MoNi 4 nanocrystals and MoO 3‐ x as dual active components dramatically boosts the hydrogen evolution reaction (HER) performance. Benefiting from high intrinsic activity, high electrochemical surface area, 3D open network, and improved electron transport, the resulting MoNi 4 /MoO 3‐ x electrode exhibits a remarkable HER activity with extremely low overpotentials of 17 mV at 10 mA cm −2 and 114 mV at 500 mA cm −2 , as well as a superior durability in alkaline medium. The water–alkali electrolyzer using MoNi 4 /MoO 3‐ x as cathode achieves stable overall water splitting with a small cell voltage of 1.6 V at 30 mA cm − 2 . These findings may inspire the exploration of cost‐effective and efficient electrodes by in situ integrating multiple highly active components on 3D platform with open conductive network for practical hydrogen production.