Facile ion-exchange synthesis of BiOI/Bi₂O₂CO₃ heterostructure for efficient photocatalytic activity under visible light irradiation

The BiOI/Bi₂O₂CO₃ heterostructural photocatalysts were synthesized by a facile ion-exchange route between Bi₂O₂CO₃ precursor and KI with ultrasonic reaction. The as-prepared BiOI/Bi₂O₂CO₃ heterostructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance absorption spectra (DRS), fourier transform infrared spectroscopy (FTIR) and photoluminescence spectra (PL). The BiOI/Bi₂O₂CO₃ heterostructures exhibited much higher photocatalytic activities than those of single Bi₂O₂CO₃ and BiOI for the degradation of Rhodamine B (RhB) under visible light irradiation. The significantly enhanced photocatalytic activity of BiOI/Bi₂O₂CO₃ heterostructures could be attributed to the formation of p–n heterojunction between p-type BiOI and n-type Bi₂O₂CO₃, which effectively separated the photogenerated electron–hole pairs. The possible mechanism of BiOI/Bi₂O₂CO₃ heterostructures as photocatalysts was proposed.