Morphology-controlled fabrication of CNT@MoS2/SnS2 nanotubes for promoting photocatalytic reduction of aqueous Cr(VI) under visible light

Abstract Heavy metal pollution has become a global environmental problem. Industrial wastewater containing hexavalent chromium Cr(VI) is particularly harmful to the environment. Effective treatment of industrial wastewater containing Cr(VI) is still difficult. In this study, functionalized hybrid nanotubes, denoted as CNT@MoS 2 /SnS 2 , were developed for the photocatalytic reduction of low concentrations of Cr(VI). First, CNT@MoS 2 hybrid nanotubes were synthesized by a one-step method. The hybrid nanotubes were coated with a sheet-like structure, which was conducive to the further assembly and growth of SnS 2 nanosheets to give CNT@MoS 2 /SnS 2 hybrid nanotubes. The hybrid nanotubes were able to absorb visible light and possessed a high photoelectron transport rate; as a result, they exhibited high photocatalytic activity under visible-light irradiation. The prepared CNT@MoS 2 /SnS 2 hybrid nanotubes displayed higher photocatalytic activity than that of other photocatalytic materials because of their narrow band gap. Degradation of 50-mg/L Cr(VI) solution by CNT@MoS 2 /SnS 2 under visible light showed that nearly 100% of Cr(VI) was removed within 90 min. The removal rate of Cr(VI) by SnS 2 was 96.3% under the same conditions, and only 80% was removed by CNT@MoS 2 . Moreover, CNT@MoS 2 /SnS 2 also completely removed Cr(VI) from 120-mg/L Cr(VI) solution in 90 min. These results indicate that CNT@MoS 2 /SnS 2 shows potential for application in environmental remediation.