Nanocomposites and nanomaterials

Electrocatalytic and photoelectrochemical properties of Y-TiO2 nanostructured films
Medyk I.A.1, Vorobets V.S.2, Kolbasov G.Ya. 2, Oblovatna S.Ya2., Karpenko S.V. 2
1 Department of Chemistry, National University of „Kyiv-Mohyla Academy”. Skovoroda str., 2, Kyiv-04070, Ukraine. 
E-mail: vorobetsvs@i.ua
2 Department of electrochemistry and photo-electrochemistry of non-metallic systems, Vernadsky Institute of General and Inorganic Chemistry of the NAS of Ukraine. Acad. Palladin Str., 32/34, Kyiv-03142, Ukraine. 

Titanium dioxide, due to its catalytic activity in many chemical processes, is widely used in solving many environmental and energy problems. The catalytic activity of titania increases greatly when rare earth doped nanoparticles are used [1]. We present study results of electrocatalytic and photoelectrochemical properties of electrodes based on nanostructured  Y-doped titanium oxide films.
The parent TiO2 and yttrium  doped TiO2 films with Y content 0.5–5 mol.% were synthesized by sol-gel method. The precursors employed were titanium tetraisopropoxide and yttrium acetate hydrate as a source of Ti and Y ions, respectively. The synthesized materials were characterized by X-ray diffraction (XRD) and ultraviolet-visible photocurrent spectra. The average size of nanoparticles calculated from the Scherrer equation was no more thаn 12 nm. The XRD results indicated that TiO2 and Y-TiO2 electrodes calcined at 500°C consisted of anatase as the unique phase. The photocurrent spectra of the Y-TiO2 electrodes (Y concentration up to 5 mol%)  showed a stronger current in the UV range and doping with yttrium shifts the photocurrent spectra to the long-wave region of the spectrum.
Modifying of TiO2 films by Y improves catalytic activity of Y-TiO2 electrodes in the reaction of oxygen electroreduction. Improvement of electrocatalytic activity in comparison with unmodified TiO2 has been observed for  films with Y content up to 2 %. The correlation between electrocatalytic activity of electrodes and energy position of conduction band  Еfb, is determined. 

1.	ˇStengl V., Bakardjieva S., Murafa N. Preparation and photocatalytic activity of rare earth doped TiO2 nanoparticles // Mater.Chem. Phys.-2009.-114.-P. 217–226.