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 highe...