Unraveling the Interfacial Charge Migration Pathway at the Atomic Level in a Highly Efficient Z‐Scheme Photocatalyst

Abstract A highly efficient Z‐scheme photocatalytic system constructed with 1D CdS and 2D CoS 2 exhibited high photocatalytic hydrogen‐evolution activity of 5.54 mmol h −1 g −1 with an apparent quantum efficiency of 10.2 % at 420 nm. More importantly, its interfacial charge migration pathway was unraveled: The electrons are efficiently transferred from CdS to CoS 2 through a transition atomic layer connected by Co–S 5.8 coordination, thus resulting in more photogenerated carriers participating in surface reactions. Furthermore, the charge‐trapping and charge‐transfer processes were investigated by transient absorption spectroscopy, which gave an estimated charge‐separation yield of approximately 91.5 % and a charge‐separated‐state lifetime of approximately (5.2±0.5) ns in CdS/CoS 2 . This study elucidates the key role of interfacial atomic layers in heterojunctions and will facilitate the development of more efficient Z‐scheme photocatalytic systems.