Fabrication and characterization of high efficiency and stable Ag3PO4/TiO2 nanowire array heterostructure photoelectrodes for the degradation of methyl orange under visible light irradiation

Ag3PO4/TiO2 nanowire array (ATNWs) heterostructure photoelectrodes were prepared by a sequential chemical bath deposition. The structure and optical properties of the ATNWs were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy and electrochemical techniques. The photocatalytic activity of the ATNWs was evaluated by photocatalytic degradation of methyl orange (MO) under visible light irradiation (λ > 400 nm). The results showed that Ag3PO4 nanoparticles were successfully formed on the surface of the TiO2 nanowires (NWs) causing no damage to the ordered structure of the nanowires. The p-type Ag3PO4 nanoparticles deposited on the n-type TiO2 NWs could promote the transfer of photo-generated holes, which inhibited the recombination of electrons and holes effectively, leading to a significant increase in the lifetime of the charge carriers. Moreover, the ATNWs show much higher photocatalytic activity and stability than that of the pure TiO2 NWs for the photocatalytic degradation of MO. The enhanced photocatalytic activity could be attributed to the visible-light photocatalytic activity of Ag3PO4 and the heterostructure between Ag3PO4 and TiO2.