Coupling with a narrow-band-gap semiconductor for enhancement of visible-light photocatalytic activity: preparation of Bi2S3/g-C3N4 and application for degradation of RhB

Abstract

A coupled system for the photodegradation of Rhodamine B dye was realized using a Bi₂S₃/g-C₃N₄ composite as a photocatalyst under visible light irradiation. The Bi₂S₃/g-C₃N₄ composite was prepared by a hydrothermal method and characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared with pure g-C₃N₄, the Bi₂S₃/g-C₃N₄ sample exhibits an enhanced photocatalytic activity and the best photocatalytic efficiency is 3.68 times more than that of pure g-C₃N₄. The obtained results indicate that a coupled system of Bi₂S₃ and g-C₃N₄ could overcome the drawback of low photocatalytic efficiency brought by electron–hole recombination and a narrow photoresponse range. On the basis of the corresponding energy band positions, the mechanism of photocatalytic activity enhancement was proposed.