Nanocomposites and nanomaterials

Designing of new photocatalytic systems based on the nanodispersed TiO2 and a polymethine dye-sensitizer 
Kobasa I.M.1, Sema O.V.1, Kropelnytska Yu.V.2
1 Yu. Fedkovych National University of Chernivtsi, 2 Kotsyubynsky St., Chernivtsi 58012, Ukraine 
E-mail: I.Kobasa@chnu.edu.ua
2 Bucovina State Medical University, 2 Teatralna Sq., Chernivtsi 58002, Ukraine

A series of new light-sensitive semiconducting materials based on TiO2 and a polymethine dye-sensitizer has been sensitized and investigated. Both symmetrical and non-symmetrical dyes were used as sensitizers while their spectral, electrochemical and energy transformation parameters were determined to compare the sensitizing efficiency. Additional information about the efficiency was recovered from analysis of the dyes’ voltammetry curves, location of the light-sensitivity zones and values of their excited redox potentials. 
Then the materials were used to develop the light-sensitive heterostructures and to determine their photocatalytic activity in the test reactions of potassium iodide oxidation and methylene blue reduction. It has been shown that application of the dye on the semiconductor’s surface results in changes in the dye’s molecules conformation followed by shifting of the light absorption bands and changes in the absorption intensity. 
The materials exhibiting comparatively higher photocatalytic activity were identified for next usage as highly effective redox catalysts.