Sol–Gel Processing of Bi2Ti2O7 and Bi2Ti4O11 Films with Photocatalytic Activity

Authors

  • Tongjit Kidchob,

    1. D.A.P., Laboratorio di Scienza dei Materiali e Nanotecnologie, Università di Sassari and CR-INSTM, Palazzo Pou Salit, Piazza Duomo 6, 07041 Alghero, Sassari, Italy
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  • Luca Malfatti,

    1. D.A.P., Laboratorio di Scienza dei Materiali e Nanotecnologie, Università di Sassari and CR-INSTM, Palazzo Pou Salit, Piazza Duomo 6, 07041 Alghero, Sassari, Italy
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  • Daniela Marongiu,

    1. D.A.P., Laboratorio di Scienza dei Materiali e Nanotecnologie, Università di Sassari and CR-INSTM, Palazzo Pou Salit, Piazza Duomo 6, 07041 Alghero, Sassari, Italy
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  • Stefano Enzo,

    1. Dipartimento di Chimica, Università di Sassari, 07100 Sassari, Italy
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  • Plinio Innocenzi

    Corresponding author
    1. D.A.P., Laboratorio di Scienza dei Materiali e Nanotecnologie, Università di Sassari and CR-INSTM, Palazzo Pou Salit, Piazza Duomo 6, 07041 Alghero, Sassari, Italy
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  • P. Gouma—contributing editor

†Author to whom correspondence should be addressed. e-mail: plinio@uniss.it

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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