Ultrathin ZnIn2S4/ZnSe heteronanosheets with modulated S-scheme enable high efficiency of visible-light-responsive photocatalytic hydrogen evolution

The photoinduced carrier transfer mechanism in heterojunction photocatalysts plays a significant role in pho-tocatalytic water splitting. However, the relationships between photocatalytic activity and different band alignments in semiconducting heteronanosheets (HNSs) are rarely reported. Here, we used the ultrathin ZnIn2S4 (ZIS) as a model, and constructed the HNSs such as ZIS/ZnSe, ZIS/ZnS with different band alignments. The time-resolved transient absorption results show that ZIS/ZnSe HNSs exhibited the S-scheme mechanism forming the internal electronic field which has more advantages in HER than the defects state trapping-mediated transfer mechanism in ZIS/ZnS HNSs. The long-lived carrier separation (>3.58 mu s) and efficient charge transfer pathways of ZIS/ZnSe HNSs contribute to a highest photocatalytic performance so far, compared with the ZIS-based photocatalysts. These results could pave the route for the design the functional HNCs with different photoin-duced carrier dynamics to establish the relationships between composite structures and properties.

Automated summary

The effects of different band alignments in semiconducting heteronanosheets (HNSs) on photocatalytic water splitting were investigated. The results showed that ZnSe-based HNSs exhibited higher photocatalytic activity compared to ZnS-based HNSs, due to the S-scheme mechanism formed by internal electric field rather than the defect trapping-mediated transfer mechanism. Moreover, the long-lived carrier separation and efficient charge transfer pathways of ZnSe-based HNSs contributed to their superior photocatalytic performance.