Structural and Morphological Study of Zirconia and Titania Sol-Gel Monolayered Films Supported on Soda-Lime Glass Substr
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Structural and Morphological Study of Zirconia and Titania Sol-Gel Monolayered Films Supported on Soda-Lime Glass Substrates Luisa F. Cueto1, Enrique Sánchez1 Leticia M. Torres-Martínez1, Gustavo A. Hirata 2, 1 Facultad de Ciencias Químicas, División de Estudios Superiores Universidad Autónoma de Nuevo León, A.P. 1864, Monterrey, N.L., México 2 Centro de Ciencias de la Materia Condensada Universidad Nacional Autónoma de México Km. 107 Carr. Tij.-Ens., Ensenada, B.C., 22860, México ABSTRACT Sol-Gel, dip-coated titaniumIV and zirconiumIV dioxide monolayered films were deposited on soda-lime glass using titanium and zirconium acetylacetonates as precursors, respectively, and their structural and morphological characterization carried out. The films were heat-treated at different temperatures, 25°C, 150°C, 300°C, and 500°C and, according to Lowangle X-Ray Diffraction analyses (XRD), it was found that TiO2 (anatase) and tetragonal zirconia were present on the substrate, when heated at 500°C. Yoshida and Yajima’s method, based on optical information given by the films transmittance UV-Vis spectra, was used to estimate film thickness, refractive index, and, using the Lorentz-Lorentz relationship, their volume fraction. Film thinning and phase formation with increasing temperature was observed, and both titania and zirconia films showed similar behavior during firing. Smooth films with a roughness value of around 2 nm are obtained for the two cases as indicated by Atomic Force Microscopy (AFM) of the surface. Also, formation temperature at around 500ºC resulted in the optimum condition to obtain clean stoichiometric TiO2 and ZrO2 thin films on glass substrates as confirmed by X-Ray Photoelectron Spectroscopy (XPS) measurements. INTRODUCTION Sol-gel ceramic and metallic thin-film coatings on inert substrates have been of recent interest due to their novel and unique properties that powders obtained by traditional hightemperature methods [1-6] or the substrate do not show [2]. Some of these properties, are of importance to optical applications, for example as heterogeneous photocatalysts for the photodegradation of pollutants, formed by conventional methods such as dip or spin coating [4,6,7]. Also, luminescent films have been grown by specialized physical film deposition methods such as laser ablation [8]. Among ceramic materials that have been widely studied, TiO2 thin film coatings are among the most relevant regarding their application as heterogeneous photocatalysts [4]. Also, it has been applied as a material exhibiting self-cleaning, anti-fogging and anti-bacterial properties [5,6]. On the other side, ZrO2 is well known for its good mechanical properties. Deposited as a film, it enhances film endurance in applications where the material must undergo extreme
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conditions [9]. Furthermore, zirconia also offers unique properties such as bifunctional catalyst, being selective in the synthesis of α-olefins from alcohols and synthesis of 1-butene from 2butanamine, and in the isosynthesis process, among othe
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