Embedding laser-generated CdTe nanocrystals into ultrathin ZnIn₂S₄ nanosheets with sulfur vacancies for boosted photocatalytic H₂ evolution

To suppress the inner charge recombination and inject vast electrons, CdTe nanocrystals are embedded into ultrathin ZnIn₂S₄ nanosheets to construct ZnIn₂S₄/CdTe heterostructures, where the nanocrystals are generated by a laser irradiation method. The optimal ZnIn₂S₄/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g, which is relatively high among the ZnIn₂S₄-based photocatalysts without noble metals. This enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur vacancies. The strong electron coupling effect, which is verified by density functional theory (DFT) calculations, impels the photo-generated electrons transfer from CdTe to ZnIn₂S₄, boosting the charge separation. Meanwhile, the sulfur vacancies existing in ZnIn₂S₄ can capture photoelectrons and act as active sites, facilitating the H₂ generation reaction. In addition, the ZnIn₂S₄ base and the ZnIn₂S₄/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena, enhancing the photocatalytic performance. This research provides new insights into the regulation of charge transfer through embedding nanocrystals.