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

Adv Mater. 2024 Nov 19:e2415138. doi: 10.1002/adma.202415138. Online ahead of print.

Abstract

Solar-driven photocatalytic green hydrogen (H2) 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 H2 production, withthe H2 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.

Keywords: charge carrier separation; photocatalysis; surface reaction dynamics; time‐resolved spectroscopy; twin‐interface junction.