Catalysts with three-dimensional porous structure for electrocatalytic water splitting

The utilization of water as a feedstock for hydrogen production via electrolysis, which yields a non-polluting product, has garnered significant interest. For the electrochemical water decomposition, the primary challenge remains the sluggish kinetics of the electrolysis process. Three-dimensional porous materials with greatly increased specific surface area can provide additional active sites and facilitate the adsorption and desorption of intermediates, benefitting their catalytic efficiency. Therefore, catalysts with three-dimensional porous structures have become one of the focused topics to address the kinetics of water electrolysis. In this review, typical materials, i.e., self-supporting porous materials and supported porous arrays, are introduced due to their great potential to replace noble metal-based catalysts. Their structural/compositional features and synthesis routines, as well as advancements in their application to the hydrogen evolution reaction, oxygen evolution reaction and overall water splitting, are summarized to analyze their merits and challenges as electrocatalysts in water splitting. Various modification strategies, including structural, defect, and hybrid engineering, are explored to elucidate their impact on catalyst performance. This review aims to explore the correlation between structure and function and is expected to offer valuable insights into the design of porous catalysts by discussing prospective research avenues.