کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
27996 44055 2010 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
SEM and Raman study of thermally treated TiO2 anatase nanopowders: Influence of calcination on photocatalytic activity
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
SEM and Raman study of thermally treated TiO2 anatase nanopowders: Influence of calcination on photocatalytic activity
چکیده انگلیسی

Titania (TiO2) nanopowders called PC 500, synthesised by the sulphate process, were annealed in air at temperatures of up to 1022 K for 30 min. The X-ray Diffraction (XRD) indicates that the thermal annealing resulted in coarsening of the average crystallite size from 13 to 72 nm. However, Scanning Electron Microscopy (SEM) reveals persistence of platelet-like structures which survive up to temperatures around 900 K. This implies that the crystals at least partially grow within the plates in 2D confinement. This implies that direct usage of Scherrer equation in this case should be approached with care. Raman spectra peak positions and the Full-Width-at-Half-Maximum (FWHM) values changed considerably after calcinations crystal growth, while, material composition and oxygen content remain unchanged. The Raman peak behaviour can be cautiously attributed to the first order phonon confinement phenomena, but both, 2D and 3D models of confinement should be accounted. The highest photoactivity, as indicated by photoinduced degradation of a mono azo dye methyl-orange (C14H14N3SO3Na), was observed in material treated at 773 K.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 211, Issue 1, 5 March 2010, Pages 59–64
نویسندگان
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