Advancing the Development of Hollow Micro/nanostructured Materials for Electrocatalytic Water Splitting: Current State, Challenges, and Perspectives

Electrocatalytic water splitting is commonly regarded as a sustainable and clean method to generate hydrogen and oxygen, which is deemed to be efficient for the utilization of renewable energy. Electrocatalysts are essential components to enhance electrochemical efficiency and optimize product yield. Hollow micro/nanostructures possess large specific surface areas, multiple voids, and tunable chemical compositions, making them suitable for use as direct catalysts or as supports for electrochemical reactions. This review summarizes recent advancements in structural and functional designs of micro/nanostructured hollow materials as electrocatalysts for an enhanced water-splitting process. We emphasize ideas and strategies to create various hollow electrocatalysts for oxygen/hydrogen evolution processes. Subsequently, a comprehensive summary of recent studies on hollow borides, carbides, oxides, phosphides, selenides, sulfides, alloys, MXenes, and various heterostructured electrocatalysts containing hollow hosts is provided. Furthermore, we highlight the current challenges and perspectives of hollow micro/nanostructures for electrocatalytic water splitting.