In this research, Bi4O5I2 and AgI nanoparticles were anchored over g-C3N4 nanosheets (denoted as NGCN/Bi4O5I2/AgI) to preparation highly impressive visible-light-driven samples. The synthesized nanocomposites were investigated by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV-vis diffuse reflectance spectroscopy (DRS), energy dispersive analysis of X-rays (EDX), electrochemical impedance spectroscopy (EIS), photocurrent density, Brunauer-Emmett-Teller (BET), and photoluminescence (PL) analyses. Among the ternary photocatalysts, the NGCN/Bi4O5I2/AgI (20%) photocatalyst illustrated the highest photoactivity in degradation of rhodamine B (RhB), which was approximately 58.4, 15.2, and 12.8 times higher than the GCN, NGCN, and NGCN/Bi4O5I2 (20%) samples, respectively. Furthermore, the center dot O-2(-) was discovered as the main species in the respective system by the quenching tests. Also, by studying the electrochemical properties, a cascade photocatalytic mechanism was suggested based on the energy bands to describe the enhanced charge carriers migration and separation, which caused impressive photocatalytic performances in degradations of four hazardous contaminants. This study highlights the rational anchoring of Bi4O5I2 and AgI nanoparticles over NGCN to prepare highly efficient photocatalysts for wastewater remediation. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.