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

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. Air-stable nanostructured Ni-based catalysts are fabricated by a protocol that 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 nickel matrix in a self-limiting manner. Reinforced by Ni-NiO co-catalysis and improved access to intensified active sites, the nanoporous Ni/NiO heterostructure catalysts exhibit exceptional activity toward electrochemical hydrogen production. image