Facile fabrication of ZnIn2S4/SnS2 3D heterostructure for efficient visible-light photocatalytic reduction of Cr(VI)

Photocatalytic method has been intensively explored for Cr(VI) reduction owing to its efficient and environmentally friendly natures. In order to obtain a high efficiency in practical application, efficient photocatalysts need to be developed. Here, ZnIn 2 S 4 /SnS 2 with a three-dimensional (3D) heterostructure was prepared by a hydrothermal method and its photocatalytic performance in Cr(VI) reduction was investigated. When the mass ratio of SnS 2 to ZnIn 2 S 4 is 1:10, the ZnIn 2 S 4 /SnS 2 composite exhibits the highest photocatalytic activity with 100% efficiency for Cr(VI) (50 mg/L) reduction within 70 min under visible-light irradiation, which is much higher than those of pure ZnIn 2 S 4 and SnS 2 . The enhanced charge separation and the light absorption have been confirmed from the photoluminescence and UV-vis absorption spectra to be the two reasons for the increased activity towards photocatalytic Cr(VI) reduction. In addition, after three cycles of testing, no obvious degradation is observed with the 3D heterostructured ZnIn 2 S 4 /SnS 2 , which maintains a good photocatalytic stability. The charge separation and visible-light absorption efficiencies of ZnIn 2 S 4 are promoted by constructing the ZnIn 2 S 4 /SnS 2 3D heterostructure. A superior photocatalytic ability for Cr(VI) reduction is obtained over the ZnIn 2 S 4 /SnS 2 3D heterostructure.