Facile synthesis of sulfate-doped Ag3PO4 with enhanced visible light photocatalystic activity

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.