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

Abstract

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 electro-reduction. 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.