Hazem R.,University of Science and Technology Houari Boumediene |
Doulache M.,University of Science and Technology Houari Boumediene |
Izerrouken M.,Nuclear Research Center Algiers |
Trari M.,University of Science and Technology Houari Boumediene
High Energy Chemistry | Year: 2013
TiO2 thin films are elaborated by sol gel on glass substrates and irradiated with 60Co γ-rays. The X-ray diffraction, UV-Visible spectroscopy and transport properties are investigated. The films are nominally non stochiometric and the conductivity occurs by thermally activated hopping of lattice polaron. The oxygen vacancies induced by γ-ray irradiation at lower dose (<10 kGy) generate mixed valences Ti 4+/3+, thus altering the transport properties. The photo-electrochemical characterisation is undertaken to evaluate the photo catalytic performance. The Mott-Schottky plots are characteristic of n type conduction from which a flat band potential of -0.62 V SCE and a donor density of 5 × 1017 cm-3 are determined for the most active film. The Nyquist plot exhibits a semi-circular arc whose center lies below the real axis, due to the constant phase element (CPE). The energy band diagram shows the potentiality of the films for the eosin photodegradation. 68% of initial concentration (10 mg L-1) disappears after 2 h of exposure to the solar light. TiO2 irradiated with gamma dose of 10 kGy shows the best efficiency, due to the resistance decrees and high electron mobility (25 cm2 V-1 s-1). The eosin oxidation follows a first order kinetic with a rate constant of 6 × 10-2 min-1. © 2013 Pleiades Publishing, Ltd.