Self-Templated Fabrication of MoNi₄/MoO_{3- x} Nanorod Arrays with Dual Active Components for Highly Efficient Hydrogen Evolution

A binder-free efficient MoNi₄/MoO_{3- x} nanorod array electrode with 3D open structure is developed by using Ni foam as both scaffold and Ni source to form NiMoO₄ precursor, followed by subsequent annealing in a reduction atmosphere. It is discovered that the self-templated conversion of NiMoO₄ into MoNi₄ 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 MoNi₄/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 MoNi₄/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.