Balancing the Charge Separation and Surface Reaction Dynamics in Twin‐Interface Photocatalysts for Solar‐to‐Hydrogen Production

Abstract Solar‐driven photocatalytic green hydrogen (H 2 ) evolution reaction presents a promising route toward solar‐to‐chemical fuel conversion. However, its efficiency has been hindered by the desynchronization of fast photogenerated charge carriers and slow surface reaction kinetics. This work introduces a paradigm shift in photocatalyst design by focusing on the synchronization of charge transport and surface reactions through the use of twin structures as a unique platform. With CdS twin structure (CdS‐T) as a model, the role of twin boundaries in modulating surface reactions and facilitating charge migration is systematically investigated. Utilizing transient absorption (TA) and time‐resolved infrared (TRIR) spectroscopies, it is revealed that CdS‐T achieves charge separation on a picosecond timescale and, importantly, the surface reaction at the twin boundary with the involvement of holes also occurs within 100 ps to 3 ns. This synchronization of charge donation and surface regeneration significantly enhances the hydrogen evolution process. Accordingly, CdS‐T exhibits superior activity for visible light photocatalytic H 2 production, withthe H 2 production rate of 55.61 mmol h −1 g −1 and remarkable stability (>30 h), outperforming pristine CdS significantly. This study underscores the transformative potential of twin structures in photocatalysis, offering a new avenue to synchronize charge transport and surface reactions.