Synthesis, Photo- and Electrocatalytic Properties of Nanostructured Y–TiO2 Films

The electrocatalytically active films based on nanodispersed titanium dioxide modified by Y3+ ions and synthesized by the sol-gel method were characterized by the X-ray diffraction (XRD) and ultraviolet-visible photocurrent spectra. Electrocatalytic properties of the TiO2 and Y–TiO2 electrodes were investigated during the process of oxygen electroreduction.The XRD results indicated that the TiO2 and Y–TiO2 powders with the yttrium content of 0.5–5 mol % calcined at 500°C had an anatase crystal structure, with the crystallite size of 10–12 nm. The electrodes based on the Y–TiO2 films were photosensitive in a wavelength range of 250–400 nm. For all investigated samples with the Y(III) content of ≤ 5 mol %, both an increase in the photocurrent quantum yield and a shift of spectra towards longer wavelengths vs. those of the undoped TiO2 were observed. The photocurrent quantum yield for the Y–TiO2 samples first increased and then decreased with increasing the Y(III) content, and reached its maximum with 2% Y–TiO2 films. It was found that doping of the TiO2 films by Y(III) improves the catalytic activity of the Y–TiO2 electrodes in the reaction of oxygen electroreduction. A correlation between photo- and electrocatalytic properties and structural changes occurring in the TiO2 films upon yttrium doping has been revealed.