In Situ Growth of Ru Nanoparticles on (Fe,Ni)(OH)2 to Boost Hydrogen Evolution Activity at High Current Density in Alkaline Media

Abstract Electrocatalytic water splitting for industrial hydrogen production at large current densities requests highly active and cost‐effective catalysts with long‐term stability. Here, conductive nickel foam is proposed to be used as a substrate to support (Fe,Ni)(OH) 2 nanosheet arrays and a reducing agent to reduce Ru 3+ ions to metallic Ru. The formed 3D self‐supported Ru/(Fe,Ni)(OH) 2 /NF (denoted as RFNOH) with a superhydrophilic surface and high conductivity ensures rapid release of gases and efficient electron transportation and mass transfer at a high current density. The resultant RFNOH requires an overpotential of only 152 mV to achieve a current density of 1 A cm −2 for hydrogen evolution reaction in 1 m KOH solution, along with excellent stability at high current density. Meanwhile, density functional theory calculations suggest that (Fe,Ni)(OH) 2 promotes the dissociation of water molecules considerably, which plays a critical role in enhancing the generation of molecular hydrogen on Ru nanoparticles. Furthermore, the proposed dual‐active site mechanism solves the problem of low water‐dissociation efficiency faced by noble metal‐based catalysts under alkaline media. This study provides a new route for the practical production of large quantities of hydrogen via electrochemical water splitting.