Change search
ReferencesLink to record
Permanent link

Direct link
Photonic crystals and photocatalysis: Study of titania inverse opals
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
2016 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

Due to an increase of human activity, an increase health risk has emerged from the presence of pollutants in the environment. In the transition to renewable and sustainable life style, treatment of pollutants could support the shifting societies. A motivation behind material research for environmental applications is to maximize the efficiency of the materials to alleviate environmental pollution.

In the case of titania, an increase of ultra-violet light absorption is needed to overcome its bandgap to produce reactive radicals, which is the basis for photocatalysis. It has been hypothesized that photonic crystal can enhance titania photocatalysis. They are structures made of at least two dielectrics with a high refractive index contrast, ordered in a periodic fashion. For a strong contrast, photonic band gaps emerge. The effect of the photonic band gap is to force complete reflection of the incoming light within its range and multiple internal reflections at its edges. By combining photonic and electronic band gap positions, it is possible to increase the absorption at the photonic band gap edges.

In this thesis, fabrication method and structural analysis of titania and alumina/titania photonic structures were presented. A thorough optical analysis was performed at all steps of fabrication – beyond what previously has been reported. The photocatalytic activity was measured with two setups. Fourier Transform Infrared spectroscopy combined with arc lamps and bandpass filters was used to monitor the degradation of stearic acid in ambient air. A home-built setup was used to degrade methylene blue in solution with ultra-violet illumination.

The results in this thesis show in general no correlation of the photocatalytic activity to the photonic band gap position, even though absorbance data displayed an increase absorption in this energy range. A more controlled environment might show the effect of the structure, as seen in some of the experiments.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. , 284 p.
Series
Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-2516 ; 126
Keyword [en]
photocatalysis, titania, inverse opal, photonic crystal, optics
National Category
Other Environmental Engineering Other Materials Engineering Other Physics Topics
Research subject
Engineering Science with specialization in Solid State Physics
Identifiers
URN: urn:nbn:se:uu:diva-300408ISBN: 978-91-554-9650-0OAI: oai:DiVA.org:uu-300408DiVA: diva2:952870
Public defence
2016-10-03, ITC 2247, Lägerhyddsvägen 1, Uppsala, 14:15 (English)
Opponent
Supervisors
Available from: 2016-09-12 Created: 2016-08-08 Last updated: 2016-09-13

Open Access in DiVA

fulltext(12360 kB)69 downloads
File information
File name FULLTEXT01.pdfFile size 12360 kBChecksum SHA-512
804045e9ad541583ec443142516cd54ae636f442d4384d916f1e60e36ed2fd0cfb91674c1ec5de796142d7941cd8807d47bff9419e85ef5d4162b42f5d76bb17
Type fulltextMimetype application/pdf
Buy this publication >>

Search in DiVA

By author/editor
Lebrun, Delphine Misao
By organisation
Solid State Physics
Other Environmental EngineeringOther Materials EngineeringOther Physics Topics

Search outside of DiVA

GoogleGoogle Scholar
Total: 69 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 306 hits
ReferencesLink to record
Permanent link

Direct link