Facile fabrication of green SnS2 quantum dots/reduced graphene oxide composites with enhanced photocatalytic performance

Photocatalytic reduction of Cr(VI) has attracted enormous research interest because it provides a clean and low-cost way for the removal of toxic Cr(VI). Despite tremendous efforts, the present great challenge in materials science is to develop highly efficient photocatalysts for Cr(VI) reduction at low cost. Here we reported new composite materials consisting of SnS2 quantum dots (QDs) grown on reduced graphene oxide (RGO) as highly-efficient photocatalysts for photocatalytic reduction of Cr(VI) under visible-light irradiation. These nanostructured materials were prepared by a simple and cost-effective one-step hydrothermal process using stannic chloride pentahydrate, L-cysteine and graphene oxide as precursors. The photocatalytic performance of SnS2 QDs/RGO composite photocatalysts in the reduction of Cr(VI) was investigated. The results showed that all SnS2 QDs/RGO photocatalysts exhibited significantly enhanced photocatalytic activities for Cr(VI) reduction and the 1.5% SnS2 QDs/RGO photocatalyst achieved the highest photoreduction efficiency of 95.3% under visible light irradiation. The enhanced photocatalytic activities of SnS2 QDs/RGO photocatalysts mainly due to excellent electron transportation ability of graphene that impedes the recombination of electron-hole pairs, and the effective charge transfer from SnS2 to grapheme was demonstrated by the significant reduction of photoluminsence intensity in SnS2 QDs/RGO photocatalysts. The present study suggests that SnS2 QDs/RGO photocatalysts are potential photoactived materials in efficient use of solar energy for the removal of Cr(VI). (C) 2016 Elsevier B.V. All rights reserved.