Nanocomposites and nanomaterials

Synthesis of nanostructured TiO2 films modified by La and their electrocatalytic properties
Garashchenko A.Yu.1, Vorobets V.S.2, Kolbasov G.Ya.2, 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 represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. No less interesting are the electrocatalytic properties of TiO2 in the oxygen reduction reaction and possibility of its use in sensor systems, the development of which is relevant today [1]. We present study results of electrocatalytic properties of  nanostructured TiO2 films modified by La.
Electrocatalytic films based on nanodispersed titanium oxide modified by La were synthesized by sol-gel method and were characterized by x-ray diffraction and ultraviolet-visible photocurrent spectra. The average size of nanoparticles was no more thаn 12 nm. 
Electrocatalytic properties of TiO2 and La-TiO2 electrodes were investigated in the processes of oxygen electroreduction. The potential of O2 electroreduction changes with the film composition. Doping by La improves catalytic activity of La-TiO2 electrodes in oxygen electroreduction reaction, that appears in decreasing of oxygen reduction potential EO2 and increasing of dynamic range of O2 electroreduction potentials. The correlation between electrocatalytic activity of electrodes investigated and energy position of conduction band  which is determined by flat band potential Еfb, is determined.
The investigated electrodes have high sensitivity to dissolved oxygen ((4-5)∙10-6 g/l) and reproducibility of characteristics in long-time cycling. These electrodes promise much as reusable electrode materials in electrochemical sensors for oxygen determination in liquids.

1.	Kolbasov G.Ya., Vorobets V.S., Blinkova L.V., Karpenko S.V. Electrodes based on TiO2 nanotubes for an electrochemical sensor of dissolved oxygen // Sensor Electronics and Microsystem Technology.-2012.-3(9).- P.39-428.