Enhanced photoelectrochemical properties of TiO2 by codoping with tungsten and silver

The Tungsten (W) and Silver (Ag) codoped TiO2 samples were successfully synthesized by hydrothermal method without any post calcination. To understand the correlation between electronic structure and photocatalytic properties, the synthesized samples were characterized using X-ray diffraction, Brunauer-Emmett-Teller specific surface area, transmission electron microscopy, ultra-violet-visible absorption spectra, and X-ray photoelectron spectroscopy (XPS), and the photocatalytic properties were evaluated under visible light irradiations. Codoping could not induce any changes in the phase and all the synthesized samples displayed pure anatase phase with spherical morphology. Visible light absorptions of the codoped samples were dramatically improved compared to the corresponding mono-doped samples. XPS analysis indicated that the dopant atoms successfully entered the TiO2 network. Results from the visible light photodegradation experiments showed that tungsten-silver codoped TiO2 possessed strong ability in photo-degrading methylene blue compared to tungsten doped TiO2 and silver doped TiO2, which was attributed to the smaller particle size, higher specific surface area, enhanced visible light absorption, and improved separation of photogenerated carriers. (C) 2014 AIP Publishing LLC.