Enhanced Solar Light Photocatalytic Activity of Ag Doped TiO2–Ag3PO4 Composites

Composites comprised of Ag3PO4 and bare TiO2 (TiO2@Ag3PO4) or silver doped TiO2 (Ag@TiO2–Ag3PO4) have been synthesized by coupling sol–gel and precipitation methods. For the sake of comparison, also the bare components have been similarly prepared. All the samples have been characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), photoelectrochemical measurements, and specific surface area (SSA) analysis. The optoelectronic and structural features of the samples have been related to their photocatalytic activity for the degradation of 4–nitrophenol under solar and UV light irradiation. Coupling Ag3PO4 with silver doped TiO2 mitigates photocorrosion of the Ag3PO4 counterpart, and remarkably improves the photocatalytic activity under solar light irradiation with respect to the components, to the TiO2–Ag3PO4 sample, and to the benchmark TiO2 Evonik P25. These features open the route to future applications of this material in the field of environmental remediation.