HREM, TEM AND XRD OBSERVATION OF NANOCRYSTALLINE PHASES IN TIO2 OBTAINED BY THE SOL-GEL METHOD

The microstructural and chemical properties of nanosized TiO2, obtaine d by the sol-gel procedure, were investigated. The specific surface ar ea of TiO2 was dependent on modifications of the general sol-gel proce dure. A gradual decrease of the specific surface area (BET) from 169.9 to 2.7 m(2)g(-1) with an increase of the calcination temperature up t o 983 K was observed. At 913 K rutile was observed, together with a sm all amount of anatase. The grain size of the anatase phase changed fro m 4.5 +/- 2 nm to 6.5 +/- 2 nm when the temperature increased up to 91 3 K. The high specific surface area, small grain size, adequate porosi ty, and favorable phase composition of nanosized TiO2, synthesized in the present work, rendered this material suitable as photoelectrode in dye-sensitized solar cells.