Few-Layer ZnInS/Laponite Heterostructures: Role of Mg Leaching in Zn Defect Formation.

Designing nanostructures with extended light absorption via defect engineering is a useful approach for the synthesis of efficient photocatalysts. Herein, ZnInS was grown hydrothermally in the modified interlayer space of Laponite, resulting in lamellae consisting of Zn-defective ZnInS several unit cells thick. In the process it was found that Mg leached from Laponite during synthesis led to the formation of Zn defects in ZnInS. This resulted in nanohybrids with light absorption extended across the visible spectrum and in improved charge transfer due to the layered structure formed via confined growth. Compared with pure ZnInS, Zn-defective ZnInS-Laponite hybrids have increased photocurrent generation and photocatalytic performance. The leaching of Mg and the resulting formation of Zn defects was attenuated by addition of 4 mM Mg to the reaction, due to a combination of shifting of the equilibrium of Mg leaching toward stability, and increased ionic strength. In summary, this work demonstrates the growth of ∼1 nm thick lamellae of ZnInS, presents a unique strategy to generate cation defects in nanomaterials and the mechanism behind it, and also provides an approach to mitigate Mg leaching in such syntheses.