Rationally designed Z-scheme CuInS2/rGO/protonated g-C3N4 heterostructure for enhanced visible-light Cr (VI) reduction

A Z-scheme CIS/rGO/p-CN heterostructure was designed. • CIS/rGO/p-CN exhibits the highest visible-light activity for Cr(VI) photoreduction. • rGO serves as the solid-state electron mediator to switch the charge transfer mode. Hexavalent chromium (Cr (VI)), a highly toxic metal ion readily soluble in aqueous environments, poses significant threats to human health. Herein, a novel Z-scheme CuInS 2 /rGO/protonated g-C 3 N 4 heterostructure was designed with rGO serving as the solid-state electron mediator between CuInS 2 and protonated C 3 N 4 . The samples were systematically characterized using XRD, FTIR, SEM, TEM, XPS, PL, and UV–vis spectroscopy techniques. This flower-like hierarchical structure CuInS 2 /rGO/protonated g-C 3 N 4 exhibits enhanced visible-light photocatalytic activity for Cr (VI) photoreduction. Specifically, it demonstrates a 98% reductive efficiency for Cr (VI) within 20 min at pH= 4 and stable photocatalytic performance. The results indicate that the integration of rGO nanosheets significantly enhances the photocatalytic performance of the CuInS 2 /rGO/protonated g-C 3 N 4 heterostructure by weakening the built-in electric field between CuInS 2 and protonated C 3 N 4 and switching the charge transfer mode from a conventional p-n junction to a Z-scheme mechanism. Download: Download high-res image (103KB) Download: Download full-size image