Self‐Limited Formation of Nanoporous Nickel Heterostructure Catalyst for Electrochemical Hydrogen Production

Abstract Nickel has risen as a viable and cost‐effective substitute to noble metal catalysts in electrochemical hydrogen production, yet developing air‐stable and highly efficient nanostructured nickel‐based catalysts remains a significant challenge. Here a facile method for creating nanoporous Ni/NiO heterostructure catalysts for electrocatalytic hydrogen production is reported. The protocol employs chemical dealloying to establish a 3D bicontinuous nanoporous structure, followed by a controlled oxidation process to in situ generate uniform NiO surface layers atop the metallic nickel matrix in a self‐limiting manner. This approach not only yields highly active nickel‐based catalysts through a simple and controlled procedure but also effectively mitigates the auto‐ignition issue inherent in nanosized Ni, thereby enhancing air stability. By leveraging the synergistic interaction between Ni‐NiO co‐catalysis and improved access to intensified active sites, the electrocatalysts exhibit superior performance in the hydrogen evolution reaction, markedly outperforming noble Pt/C catalysts, and high stability in alkaline environments. The exploration of self‐limiting oxidation in nanostructured transition metals opens new avenues for developing advanced metal/oxide heterostructure catalysts for diverse energy applications.