Anodically grown Si-W codoped TiO2 nanotubes and its enhanced visible light photoelectrochemical response

Si-W codoped TiO2 nanotubes were synthesized using a one-step anodization process with the presence of silicotungstic acid in the electrolyte. X-ray photoelectron spectroscopy results indicated that the content of Si and Win the TiO2 nanotubes was proportional to the concentration of the silicotungstic acid in the solution. More absorption in the visible light region was observed for the resulted samples from the UV-vis diffuse reflectance spectra. An enhanced photoelectrochemical visible response was demonstrated for the codoped samples and the photocurrent was 2.5 times larger than that of pristine TiO2 nanotubes under visible light irradiation. More negative flat band potential and a higher carrier density were associated with the introduction of dopants Si and W. This work demonstrated a feasible and simple method to fabricate doped TiO2 with controlled doping content based on the corresponding additives in the anodization electrolyte. (C) 2012 Elsevier B.V. All rights reserved.