In situ construction of the BiOCl/Bi2Ti2O7 heterojunction with enhanced visible-light photocatalytic activity

Abstract

Herein, a BiOCl/Bi₂Ti₂O₇ heterojunction was prepared as an efficient visible light-driven photocatalyst through an in situ hydrothermal method, and its photocatalytic properties were investigated via a comparable method. Its structure, morphology and composition were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). The formation of a heterojunction between BiOCl and Bi₂Ti₂O₇ was also confirmed via transmission electron microscopy (TEM). Moreover, the optical and photocatalytic properties of BiOCl, Bi₂Ti₂O₇ and BiOCl/Bi₂Ti₂O₇ heterojunction composites with different BiOCl : Bi₂Ti₂O₇ mass ratios were investigated. Compared to the case of pure BiOCl, the absorption spectra of the BiOCl/Bi₂Ti₂O₇ heterojunction were extended to the visible light region, and the photocatalytic activities were also enhanced. Moreover, the enhancement mechanism of the photocatalytic activity was studied via photocurrent density tests, electrochemical impedance spectroscopy (EIS) and trapping experiments.