Effect of Secondary Metals Dopant on Morphology, Microstructure and Photocatalysis Activity of Electrospun Titania Fibers

Name: Jerawut Kaewsaenee

keyword: Titania I Nanofibers

Abstract: In this research, the sol-gel and electro spinning techniques were combined to produce PVP/titanium (IV) oxide composite fibers from solutions containing PVP and titanium tetraisopropoxide. By aluminium nitrate nonahydrate or magnesium nitrate hexahydrate and/or zirconyl (IV) nitrate hydrate was added to the solutions as a source of metal dopant, respectively. Upon calcination of the as-spun fibers, neat and metal-doped titania fibers were obtained. Diameters of as-spun composite fibers were in the range of about 100-200 nm, while those of the as-calcined fibers were in the range of about 80-200 nm. For AIdoped titania fibers, increasing the calcination temperature resulted in the decrease in the fraction of anatase phase within the fibers, as well as the increase in titania crystallite sizes. The presence of aluminium dopant, however, was found to greatly affect both physical and chemical properties of the synthesized titania fibers. Aluminium nitrate accelerated condensation of titanium oxide species during the sol-gel process, which resulted in increased viscosity of the spinning solution and consequently affected the diameters of the as-spun fibers. Aluminium dopant also played the major roles in both regulating the nucleation rate during crystallization of titania and controlling the growth mechanism of titania crystallites. As a result, the aluminium dopant caused the crystallite size of titania to decrease and retarded phase transformation from anatase to rutile. For Mg-doped or Zsdoped titania fibers, the presence of either magnesium or zirconium dopant affected both the physical and chemical properties of the as-synthesized titania fibers and even retarded the formation of the rutile phase. Various characterization techniques were employed to confirm the increased content of Ti3+ defects and oxygen vacancies within the titania structures resulting from the presence of the metal dopants. These defects were found to trap photoexcited charges (i.e., electrons and holes), thus retarding the recombination of electron-hole pairs. This led to an enhancement of the photocatalytic activity of the titania structures.

King Mongkut's University of Technology Thonburi. KMUTT Library

Address: BANGKOK

Email: info.lib@mail.kmutt.ac.th

Name: Pinpan Visal-athaphand

Role: Advisors

Created: 2011

Modified: 2012-03-28

Issued: 2012-03-22

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: PHY607

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Physics

Grantor: King Mongkut's University of Technology Thonburi

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