Facile synthesis of CNTs/CaIn 2 S 4 composites with enhanced visible-light photocatalytic performance

In response to the continuous concerns to environmental contamination and energy crisis, visible-light-driven photocatalysis has attracted broad attention for its potential applications in environment remediation and energy conversion. In this study, visible-light-responsive CNTs/CaIn2S4 (CIS) composite photocatalyst was designed and synthesized by a facile one-step microwave hydrothermal method. The effects of CNTs content on the crystallinity, structure, light absorption, specific surface area and photocatalytic performance of CIS semiconductor were systematically studied. The results demonstrated that the prepared composite with a suitable amount of CNTs exhibited an apparently enhanced photocatalytic activity than bare CIS for both X-3B dye degradation and H2 production under visible-light irradiation. The optimal content of CNTs was found to be 1 wt%. The corresponding apparent rate constants of photocatalytic degradation and H2-production rate are about two times as that of bare CaIn2S4 semiconductor. Comprehensive analysis demonstrated that such enhancement was mainly attributed to the strong coupling interface between CNTs and CIS, which largely improved the separation efficiency of photogenerated charge carriers in space. However, excessive CNTs resulted in a decreased photocatalytic activity due to the shield of active sites and absorbed photons on the surface of CIS photocatalyst. This work could shed new light on the design and synthesis of carbon material/chalcogenide composite with enhanced photocatalytic performance.