Synthesis and characterization of mesoporous catalytic materials = 메조포러스 촉매 물질의 합성과 특성 규명에 관한 연구

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Mesoporous molecular sieves have been synthesized through supramolecular templating route using surfactant micelles. The physicochemical properties of the mesoporous molecular sieves for practical applications have been investigated. The MCM-41 material with long-range structural order and textural uniformity was obtained through the control in the reaction equilibrium by addition of acetic acid during the conversion of sodium silicate and hexadecyltrimethylammonium chloride to an MCM-41 phase. The MCM-41 containing aluminum within the framework (AlMCM-41) has been found to exhibit an ion-exchange capacity similar to that of conventional zeolite. The MCM-41 is stable up to 1000 K in $O_2$ flow saturated with water vapor at room temperature. The structure of the MCM-41 material disintegrates in distilled water around 370 K due to silicate hydrolysis, in contrast to its high stability in 100%-steam of 1 atmospheric pressure up to 820 K. A synthetic route to disordered mesoporous molecular sieves designated as KIT-1 (KIT stands for Korea Advanced Institute of Science and Technology) has been developed using polymerization of silicate anions surrounding surfactant micelles in the presence of various salts. Transmission electron micrograph images of platinum wire grown inside the mesopores show that the KIT-1 has a three-dimensional, disordered network of short wormhole-like channels with uniform widths, compared with one-dimensional channel structure of the MCM-41. The structure of the KIT-1 material exhibits outstanding hydrothermal stability. The effects of salts on the structure and hydrothermal stability of the mesoporous molecular sieves have been investigated as a function of the hydrothermal reaction time. The addition of the salts causes a systematic change from the hexagonal mesophase to a disordered "wormhole-like" mesostructure having the channels interconnected. This effect has been found to be determined by the initial composition of starting material...
Advisors
Ryoo, Ryongresearcher유룡researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
1999
Identifier
151513/325007 / 000955085
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 1999.2, [ xii, 103 p. ]

Keywords

Synthesis; Mesoporous molecular sieve; Stability; 메조포러스 촉매 물질; 합성; Zirconia; Ammoxidation

URI
http://hdl.handle.net/10203/31504
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=151513&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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