Ternary 3D architectures of CdS QDs/graphene/ZnIn2S4 heterostructures for efficient photocatalytic H2 production

Abstract

Highly efficient hydrogen production can be achieved by three-dimensional (3D) architectures of CdS quantum dots (QDs) incorporated in the porous assembly of marigold-like ZnIn₂S₄ heterostructures coupled with graphene, leading to an efficient electron transfer between them and the enhancement of the ZnIn₂S₄ photostability. The as-prepared samples were characterized by X-ray diffraction, electron microscopy, Brunauer–Emmett–Teller analysis, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance absorption spectra, and photoluminescence spectra. Especially, 3 wt% CdS QDs decorated ZnIn₂S₄ heteroarchitectures showed a high rate of H₂-production at 1.9 mmol h⁻¹, more 2.7 times than that of ZnIn₂S₄. The rate was further increased to 2.7 mmol h⁻¹ with a high quantum efficiency of 56% using the 3 wt% CdS QDs decorated ZnIn₂S₄ composites coupled with 1 wt% graphene (about 4 times higher than that of the pure ZnIn₂S₄). Moreover, the CdS QDs/graphene/ZnIn₂S₄ exhibited strong durability due to the high hydrothermal stability of the flower-like structure and the inhibition of CdS leaching owing to its strong interaction with ZnIn₂S₄. The excellent photocatalytic performance is ascribed to the enhanced light absorption and the improved separation of photogenerated carriers. This finding highlights the validity of 3D semiconductor heterostructures as effective building blocks for exploring efficient visible-light-active photocatalysts.