Search

A novel and highly efficient photocatalyst of Cd 0.5 Zn 0.5 S@ZIF-8 nanocomposite has been developed by a facile self-assembly strategy. This is the first report on the application of Cd x Zn 1−x S and metal-organic framework (MOF) nanocomposite as photocatalysts for the reduction of Cr(VI). The resulting Cd 0.5 Zn 0.5 S@ZIF-8 exhibited higher photocatalytic activity than that of pristine Cd 0.5 Zn 0.5 S and ZIF-8. Particularly, the CZS@Z60 composite with 60 wt% of ZIF-8 exhibited a photocatalytic activity that is about 1.6 times as high as that of Cd 0.5 Zn 0.5 S. The dominant reason for the improved photocatalytic reduction potential is proved to be the newly-formed interfacial S Zn bonds that firmly connect Cd 0.5 Zn 0.5 S and ZIF-8 and substantially improve the separation efficiency of photo-excited electrons and holes. The newly-formed chemical bonds are confirmed by XPS analyses, and the prolonged lifetime of photo-excited electrons is evidenced by the electrochemical measurement of photocurrent, which shows that the photocurrent on Cd 0.5 Zn 0.5 S@ZIF-8 is much higher than that of Cd 0.5 Zn 0.5 S and ZIF-8. This study clearly demonstrates that the MOF-based composite nanomaterials hold great promises for applications in the field of environmental remediation and for design of novel photocatalytic materials. [ABSTRACT FROM AUTHOR]

• Bi 2 S 3 /BiOCl@ZnIn 2 S 4 composite with Bi 2 S 3 as transition layer was constructed. • Bi 2 S 3 /BiOCl@ZnIn 2 S 4 shows high activities on Cr(VI) photocatalytic reduction. • The efficiency is 3.3 and 24.1 times as high as that of ZnIn 2 S 4 and Bi 2 S 3 /BiOCl. • The intimate heterostructure causes the boosted photocatalytic activity. Delicate construction based on 2D epitaxial heterostructure can be an effective route to adequately excavate and utilize its superiorities. Here, a core-shell Bi 2 S 3 /BiOCl@ZnIn 2 S 4 hierarchical heterostructure is rationally designed and built by Bi 2 S 3 epitaxial growth on two-dimensional template-like BiOCl and ZnIn 2 S 4 nanosheets in-situ growth. The epitaxial growth of Bi 2 S 3 on BiOCl endows the tight contact between them. More importantly, Bi 2 S 3 as the interlayer could offer an extra intimate junction to ZnIn 2 S 4 due to the chemical interaction of S2− between Bi 2 S 3 and ZnIn 2 S 4. Such a Bi 2 S 3 /BiOCl@ZnIn 2 S 4 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 ZnIn 2 S 4 and Bi 2 S 3 /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. [ABSTRACT FROM AUTHOR]