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Photodegradation kinetics of stearic acid on UV-irradiated titania thin film separately followed by optical microscopy and Fourier transform infrared spectroscopy

Paper ID Volume ID Publish Year Pages File Format Full-Text
46996 46455 2011 6 PDF Available
Title
Photodegradation kinetics of stearic acid on UV-irradiated titania thin film separately followed by optical microscopy and Fourier transform infrared spectroscopy
Abstract

We use optical microscopy for observing the photocatalytical decomposition of SA on titania film during exposure to a simulated solar illumination. The titania films were prepared via sol–gel and deposited on a borosilicate glass substrate by dip-coating. A low amount of SA was deposited by dipping the titania film in a methanolic SA solution. Optical micrographs showed that the deposited SA forms islands with variable heights and sizes and that upon UV-irradiation, these latter decomposed gradually from the edges towards the center. The SA photodecomposition as evaluated by measuring the integrated IR absorbance of SA in the 2700–3000 cm−1 region, proceeded according to a pseudo first-order kinetics with respect to SA. By contrast, it was of the zero-order type when monitoring the decomposition of an individual SA island by microscopy. From these results, we showed that the pseudo first-order kinetics is the result of a collective effect of many independent and parallel zero-order reactions with variable durations. This scenario describes well both the experimental data and those reported in literature.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Stearic acid (SA) deposited on TiO2 film forms islands of variable sizes and heights. ► Upon UV light, overall SA decomposes according to a pseudo first-order kinetics. ► However, the decomposition of an individual SA island is of the zero-order type. ► Collective effect of islands disappearance explains the pseudo first-order kinetics.

Keywords
Titanium oxide; Thin film; Photocatalysis; Self-cleaning surface; Stearic acid
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Photodegradation kinetics of stearic acid on UV-irradiated titania thin film separately followed by optical microscopy and Fourier transform infrared spectroscopy
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 103, Issues 1–2, 14 March 2011, Pages 85–90
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us