Photocatalytic properties of titanium based mixed oxides prepared by sol-gel and gas-phase synthesis = 졸-겔법과 기상법으로 제조한 티타늄계 혼합산화물의 광촉매 특성

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Titanium based photocatalyst was prepared by the sol-gel technique and the gas-phase reaction. The photoactivity of prepared photocatalysts was investigated by the decomposition of trichloroethylene as a model reaction. X-ray diffraction, BET, SEM or TEM photographs, FT-IR, UV/visible absorption, ESR, and photoluminescence(PL) spectroscopy were used to characterize all prepared catalysts. It was tried to determine the priority in parameters affecting the photoactivity of titanium based photocatalyst. For nanophase $TiO_2$ prepared by the sol-gel method, it was found that the heat treatment at high temperature without forming rutile phase is a key to the high photocatalytic activity due to the increase of crystallinity and the reduction of bulk defects. From the analysis of ESR and PL spectra, it was clear that the surface active site like $O^-$ is produced and leads the enhancement of photoactivity with increasing the calcination temperature. The crystallite size of titania particle was controlled at a fixed particle size and surface area by the spray pyrolysis. The photoactivity of non-porous titania particles increased monotonically with increasing the crystallite size. In further investigation on the photoactivity of nanometer size titania prepared by the gas-phase pyrolysis of titanium-tetra-isopropoxide, it was confirmed that the crystallinity is more important than the surface area to enhance the photoactivity for TCE decomposition regardless of the preparation method. The photoactivity of nano-size titania prepared by the gas-phase oxidation of $TiCl_4$ is proportional to the relative density of surface OH groups regardless of the content of rutile phase. How much surface OH groups exist on the surface was the primary factor for determining the photoactivity of nano-size titania particles. It was also found that the direct preparation of anatase phase of large crystallite size without any further post heat treatment is crucible to get a high photoacti...
Advisors
Park, Seung-Binresearcher박승빈researcher
Description
한국과학기술원 : 화학공학과,
Publisher
한국과학기술원
Issue Date
2001
Identifier
165668/325007 / 000975346
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학공학과, 2001.2, [ xvii, 231 p. ]

Keywords

졸-겔법; 광촉매; 티타니아; 트리크로로에틸렌; 분무열분해; Photocatalyst; sol-gel method; spray pyrolysis; titania; trichloroethylene

URI
http://hdl.handle.net/10203/28851
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=165668&flag=dissertation
Appears in Collection
CBE-Theses_Ph.D.(박사논문)
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