Sulfate-doped Ag3PO4 photocatalysts were successfully synthesized via a simple precipitation method. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirmed that SO42- ions were incorporated into the lattice of Ag3PO4 by replacing PO43-. The crystalline structure and optical absorption behavior of Ag3PO4 remain unchanged after SO42- doping. However, SO42--doped Ag3PO4 catalyst with 0.50 at% SO42- concentration ratio exhibited remarkably enhanced photocatalytic activity, and completely decomposed rhodamine B (RhB) and methylene blue (MB) in 4 and 5 min under visible light irradiation, respectively. Its degradation rate constant was more than 5 times higher than that of pristine Ag3PO4. The high photocatalytic performance is attributed to the fact that doping SO42- into Ag3PO4 lattice can improve the separation efficiency of photogenerated electron-hole pairs and hinder their recombination. In addition, the results of density functional theory (DFT) calculations indicate that SO42- substitution can effectively tune the electronic structures of Ag3PO4, thus resulting in high photocatalytic activity under visible light irradiation. (C) 2016 Elsevier B.V. All rights reserved.