Novel synthesis of bismuth oxyiodide/graphitic carbon nitride nanocomposites with enhanced visible-light photocatalytic activity

Abstract

The first systematic synthetic study of bismuth oxyiodide/graphitic carbon nitride (BiO_xI_y/g-C₃N₄) nanocomposite preparation using a controlled hydrothermal method is reported. The structure and morphology of BiO_xI_y/g-C₃N₄ photocatalysts are characterized by XRD, TEM, FT-IR, HR-XPS, FE-SEM-EDS, UV-vis-DRS and BET. The photodegradation activities are evaluated against the decolorization of crystal violet (CV) in aqueous solution under visible light illumination. In particular, the catalytic performance illustrates the best reaction rate constant, being 0.170 h⁻¹ using Bi₇O₉I₃/Bi₅O₇I/g-C₃N₄ composite as the photocatalyst; which is 5, 4, and 1.5 times higher than the reaction rate constant of BiOI, g-C₃N₄, and Bi₇O₉I₃/Bi₅O₇I, as photocatalysts, respectively. From the quenching effects of different scavengers, the EPR results demonstrate that the reactive O₂˙⁻ plays the major role and h⁺ and ˙OH play minor roles in the CV degradation. The probable photodegradation mechanisms are proposed and discussed in this research. This work is useful for the synthesis of BiO_xI_y/g-C₃N₄ and the photocatalytic degradation of the CV for future applications in environmental pollution and control.