Abstract

A new sol–gel synthesis based on chloride compounds as precursors has been used to prepare bismuth titanate (BT) films. The films have been deposited by dip-coating and fired at different temperatures in air; they remain amorphous up to 500°C, and crystallize into the pyrochloric cubic phase Bi₂Ti₂O₇ between 600° and 700°C while at higher temperatures of firing the stable Bi₂Ti₄O₁₁ monoclinic phase is formed. The films have been characterized by X-ray diffraction analysis at gracing incidence, X-ray photoelectron spectroscopy, ellipsometric spectroscopy, UV–visible absorption, and atomic force microscopy. The photocatalytic properties of the films have been evaluated by exposing a methyl orange solution containing the BT films to UV light. The test has shown that the Bi₂Ti₂O₇ films have a higher activity in comparison with reference anatase titania films.

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