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Abstract: Anatase (TiO2) thin films were obtained by immersion of glass plates into a titanium sol–gel precursor followed by calcination at 450°C for 3h. The Raman results for the CO2 laser irradiated TiO2 films show that laser radiation is able to promote favorable changes of anatase phase in anatase/rutile mixtures. Nevertheless, the transformation process level depends on laser characteristics and scan speed of the radiation treatment. [Copyright &y& Elsevier]

Abstract: Thin films of paramelaconite, tenorite and their mixtures were deposited on fiberglass substrate by chemical vapor deposition and catalytically evaluated by isopropanol oxidation at low temperatures between 150 and 275°C. Copper oxides were deposited using bis(2,4-pentanedionato)copper(II) as a precursor and oxygen as carrier-reactant gas. Original crystalline phases deposited on fiberglass at different temperatures or formed subsequently were characterized by several analytical techniques. Films gave crystallite sizes from 6.5 to 8.4nm and a thickness around 230nm. The fiberglass with a paramelaconite film showed a relatively high catalytic activity, more than 40%, at 250°C. Nevertheless, the fiberglass with a tenorite film exhibited a catalytic activity of only 10% at the same temperature. Above 250°C the paramelaconite experienced a notable deactivation after which the catalytic activity decreased to 6.7% at 350°C and after this, the catalyst could not be reused. This activity loss was probably due to changes in the chemical phases on fiberglass by effect of temperatures above 250°C. [Copyright &y& Elsevier]

Abstract: Substrate dipping in a composite sol–gel solution was used to prepare both smooth and rough thin films of titanium dioxide (TiO2) on commercial fiberglass. The deposition of a composite film was done in a beaker using a solution of titanium (IV) isopropoxide as the sol–gel precursor and cetyltrimethyl ammonium bromide as the surfactant. In order to establish a correlation between experimental conditions and the titanium oxide produced, as well as the film quality, the calcined samples were characterized using Raman spectroscopy, UV–vis spectrophotometry, scanning electron microscopy and atomic force microscopy. One of the most important results is that a 61-nm TiO2 film was obtained with a short immersion of fiberglass into the sol–gel without surfactant. In other cases, the deposited film consisted of a titanium precursor gel encapsulating micelles of surfactant. The gel films were converted to only the anatase phase by calcining them at 500 °C. The resulting films were crystalline and exhibited a uniform surface topography. In the present paper, it was found that the TiO2 films prepared from the sol–gel with a surfactant showed a granular microstructure, and are composed of irregular particles between 1.5 and 3 μm. Smooth TiO2 films could have useful optical and corrosion-protective properties and, on other hand, roughness on the TiO2 films can enhance the inherent photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Anatase thin films (<200nm in thickness) embedding Degussa P25 TiO2 were prepared by sol–gel method. TiO2-anatase thin films were deposited on a fiberglass substrate and then ground to obtain glass microrods containing the composite films. The film structure was characterized using Raman spectroscopy, atomic absorption and UV–vis spectrophotometry, and atomic force microscopy. The photocatalytic activity of the composite films, calcined at 450°C, and the regeneration of the activity under the same experimental conditions, were assessed using gas chromatography to study the photodegradation of phenol, an industrial pollutant, in water under 365nm irradiation. The film with 15.0wt.% of P25 TiO2 was found to be more photoactive (54ppm of degraded phenol at 6h of illumination) than the other ones. [Copyright &y& Elsevier]

Cu2O–CuO and CuO thin films on a fiberglass substrate were prepared by chemical vapor deposition (CVD) and then catalytically evaluated by cyclohexane oxidation. The fiber with a Cu2O–CuO film showed a high catalytic activity at low temperatures, for example 43% at 350 °C, and a good selectivity to cyclohexanol production (37% at 300 °C). The fiber with a CuO film exhibited a higher catalytic activity, for example 48% at 350 °C, with a high yield of cyclohexanone (37% at 250 °C). A CuO/SiO2 catalyst with the same CuO content gave a result similar to the CuO/fiberglass system under the same conditions examined but, on the other hand cyclohexane was cleaved giving a higher selectivity to hexenes, 30% at 250 °C. The effect of reaction temperature on the catalytic activity and selectivity of cyclohexane oxidation were investigated. At 300 °C the steady-state catalytic performance of the CuO/fiberglass experienced a slight deactivation after 4 h time-on stream from 40% to 38% of conversion, after which, the catalyst could be reused apparently without any activity loss. [Copyright &y& Elsevier]