Particulate Photocatalytic Water Splitting for Solar Energy Conversion: From Material Design to Scalable...

Photocatalytic water splitting using particulate semiconductors represents a promising strategy for sustainable hydrogen production driven by solar energy. However, realizing practical solar photocatalytic hydrogen generation requires not only the development of highly efficient photocatalyst materials but also the design of integrated systems that are scalable, stable, and economically viable. This review presents a comprehensive overview of recent advances in photocatalytic material design, photogenerated charges regulation, surface catalysis, and scalable system-level integration for overall water splitting. Emphases are placed on emerging light-absorbing materials with tunable band structures, strategies to enhance photogenerated charge separation, innovations in dual-cocatalyst engineering, and reverse reaction suppression techniques. Recent progresses in Z-scheme photocatalytic systems are also highlighted, which offer alternative paradigms for achieving solar water splitting. Furthermore, advancements toward scalable applications are further presented, including the development of photocatalytic panel reactors and the hydrogen farm project (HFP) strategy, which offers a practical solution for solar energy storage and conversion without the need for H₂/O₂ separation. Looking ahead, despite significant progress, key challenges such as limited solar-to-hydrogen (STH) efficiencies, suboptimal visible-light harvesting, and scale-up constraints persist. Addressing these issues through interdisciplinary research will be pivotal in realizing practical solar hydrogen production and advancing a sustainable energy future.