Awakening the Substrate: Design of Foam Metal Electrodes for Water Electrolysis

Electrochemical water splitting is a promising environmentally friendly method for green hydrogen production. Efficient, low-cost, non-noble-metal electrocatalysts with high activity and long-term stability are essential for accelerating both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Therefore, metal foams, with their three-dimensional porous architectures, high specific surface areas, interconnected open channels, and excellent electrical and thermal conductivities, have attracted significant attention as ideal catalyst supports. Recent efforts have focused on growing composite catalysts on metal foams, typically by incorporating exogenous active species and constructing nanostructures. However, these methods often face challenges, such as complex synthesis, limited structural control, and poor long-term durability. Alternatively, direct modulation of the intrinsic structure and surface electronic configuration of the metal foam, without the need for adding foreign materials, is a simple and effective strategy that enhances the catalytic performance while also enabling a deeper mechanistic understanding. This review systematically summarizes recent progress in the design of self-supporting metal foam electrodes, emphasizing surface engineering and in situ structural modulation strategies. It also offers perspectives on future research directions and technological applications, providing theoretical insights and practical guidance for the development of advanced electrocatalysts for sustainable hydrogen production.