Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6454970 | Applied Catalysis B: Environmental | 2017 | 9 Pages |
â¢The absolute crystallinity of partly cristalline brookite samples was determined by a facile method.â¢Various brookite samples were tested for two different photocatalytic reactions.â¢A correlation among crystallinity, oxidant power and selectivity of the samples was found.
This study reports a method to determine the absolute crystallinity of partly crystalline brookite TiO2 photocatalysts. A natural, a commercial and various home-prepared brookite powders were characterized by X-ray diffraction analysis, Raman spectroscopy, scanning electron microscopy, UV-vis diffuse reflectance spectroscopy and nitrogen adsorption measurements. The absolute crystallinity was calculated from the ratio between the full width at half maximum intensity of the (121) X-ray diffraction peaks of the brookite samples and the (111) peak of CaF2 as internal standard. The photocatalytic activity of the powders was tested employing the photodegradation of 4-nitrophenol as well as the selective oxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde (p-anisaldehyde) under UV irradiation. The results indicated that crystallinity positively influenced the photooxidation of 4-nitrophenol and 4-methoxybenzyl alcohol but reduced the selectivity toward the synthesis of p-anisaldehyde.
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