Significant stability enhancement in photocatalytic CO₂ reduction via flow-driven strategies

Achieving long-term stability remains a major challenge in photocatalytic CO₂ reduction. Unlike natural photosynthesis, most artificial systems exhibit severe activity losses within hours due to catalyst deactivation and surface degradation. This study investigates the effect of continuous CO₂ and H₂O flow during the photocatalytic process. Under optimized flow conditions, widely used photocatalysts such as TiO₂, ZnO, CdS, and C₃N₄ show up to 50-fold improvement in operational stability, with TiO₂ retaining 80% of its initial activity over 15 days. CO₂ flow plays a more dominant role than H₂O flow, mitigating product accumulation and preventing catalyst deactivation. Surface and structural analyses reveal that systems without flows suffer from product and intermediate accumulation, while flow-enabled systems maintain clean catalytic surfaces. X-ray absorption spectroscopy confirms the suppression of structural degradation under flow. Here, we establish flow control as a design principle for durable photocatalytic CO₂ reduction, providing a pathway for scalable solar-to-chemical energy conversion.