Bismuth sulfide bridged hierarchical Bi2S3/BiOCl@ZnIn2S4 for efficient photocatalytic Cr(VI) reduction

Delicate construction based on 2D epitaxial heterostructure can be an effective route to adequately excavate and utilize its superiorities. Here, a core-shell Bi2S3/BiOCl@ZnIn2S4 hierarchical heterostructure is rationally designed and built by Bi2S3 epitaxial growth on two-dimensional template-like BiOCl and ZnIn2S4 nanosheets in-situ growth. The epitaxial growth of Bi2S3 on BiOCl endows the tight contact between them. More importantly, Bi2S3 as the interlayer could offer an extra intimate junction to ZnIn2S4 due to the chemical interaction of S2- between Bi2S3 and ZnIn2S4. Such a Bi2S3/BiOCl@ZnIn2S4 composite was explored for visible-light-driven reduction of Cr(VI), and much satisfactory performance was achieved, which is about 3.3 and 24.1-fold increase compared to that of ZnIn2S4 and Bi2S3/BiOCl respectively. Efficient generation, separation and transfer of photo-generated charge carriers inherited from this ternary hierarchical composite made significant contributions to the highly elevated photocatalytic activity. This work may stimulate the construction of multiple hierarchical composites based on 2D epitaxial heterostructure material for efficient photocatalysis or other optoelectronics.