Bridging Scales in Solar-Driven Water Splitting: Pathways to System Integration

Artificial photosynthesis, which converts and stores solar energy as chemical energy, holds immense potential for promoting sustainable development and achieving carbon neutrality. Solar-driven water splitting offers an ideal method for storing solar energy, with one of the most promising approaches based on efficient particulate photocatalysts. In recent years, significant progress has been made in particulate photocatalyst-based water splitting systems, from fundamental scientific research to exploratory practical applications. However, to date, no photocatalytic water splitting system has achieved the efficiency required for practical applications. The development of high-performance photocatalysts and optimized photocatalytic systems is urgently needed. This review examines the crucial factors limiting the activity of photocatalysts for overall water splitting and summarizes design strategies to enhance photocatalyst performance and overcome these barriers. The design and modification strategies for high-efficiency photocatalysts are highlighted, including bandgap regulation, localized surface plasmon resonance, morphology control, crystal facet engineering, heterostructures, cocatalysts, and external-field association. Additionally, the scalability of using particulate photocatalysts for overall water splitting driven by natural sunlight is discussed. Finally, insights into advanced strategies for improving the performance of particulate photocatalysts are provided, and perspectives on the future development of solar water splitting systems for commercial applications are offered.