Photochemical synthesis and characterization of Ag/TiO2 nanotube composites

TiO2 nanotubes were fabricated by a hydrothermal method. Silver nanoparticles with diameters around 3-5 nm were loaded onto the surface of TiO2 nanotubes via a deposition approach followed by a photochemical reduction process under ultraviolet irradiation. Transmission electron microscopy (TEM), N-2 adsorption measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-vis), and fluorescence spectroscopy (FL) were applied to characterize the as-prepared Ag/TiO2 nanotube composites. The photocatalytic activity of the as-prepared materials was investigated by photodegrading of methyl orange. The results showed that silver particles were in zero oxidation state and highly dispersed on the surface of TiO2 nanotubes when the concentration of Ag+ was low. The presence of metallic silver can help the electron-hole separation by attracting photoelectrons. The Ag/TiO2 nanotube composites with a suitable amount of silver showed a further improvement on the photocatalytic activity for degradation of methyl orange in water.