Type-I CdSe/ZnS Heteronanoplatelets Exhibit Enhanced Photocatalytic Hydrogen Evolution by Interfacial Trap-Mediated Hole Transfer
Jiangzhi Zi, Yueqi Zhong, Zhao Li, Fan Wu, Weiwei Yang, Zichao Lian
Abstract
Photoinduced carrier transfer pathways affect the optical and electronic properties of nanomaterials for photocatalytic H2 evolution. The role of defects in semiconductor nanocrystals can improve our understanding of photocatalytic mechanisms. Here, we constructed various types of heterojunctions in CdSe/ZnX (X: S, Se) heteronanoplatelets (HNPLs). These were synthesized via heteronucleation and growth on CdSe nanoplatelets (NPLs). The HNPLs were used to identify novel photocatalytic mechanisms in H2 evolution under visible-light irradiation. Time-resolved transient absorption and photoluminescence spectroscopic results suggest that CdSe/ZnS HNPLs with interfacial anomalous type-I hole transfer have advantages in terms of efficient charge separation and photocatalytic H2 evolution over type-II CdSe/ZnSe HNPLs and pristine CdSe NPLs. These results clarify defect-mediated carrier transfer in visible-light-driven photocatalytic H2 evolution.