Ryong Ryoo

Ordered carbon molecular sieves exhibiting Bragg diffraction of X-ray lines have been synthesized for the first time, using mesoporous silica molecular sieves as the template. Sucrose was converted to carbon inside the mesopores of the silica molecular sieves through a mild carbonization process using a sulfuric acid catalyst. The carbon molecular sieves were obtained after the removal of the silica framework using an aqueous solution of sodium hydroxide. The X-ray diffraction, transmission elec

Ordered mesoporous carbons have recently been synthesized using ordered mesoporous silica templates. The synthesis procedure involves infiltration of the pores of the template with appropriate carbon precursor, its carbonization, and subsequent template removal. The template needs to exhibit three-dimensional pore structure in order to be suitable for the ordered mesoporous carbon synthesis, otherwise disordered microporous carbon is formed. MCM-48, SBA-1, and SBA-15 silicas were successfully us

A new synthesis route to high-quality large mesoporous cubic Ia3d silica is reported, utilizing a triblock copolymer (EO20PO70EO20)-butanol mixture for the structure direction in aqueous solution.

Microporosity and connectivity of ordered mesopores of SBA-15 silica were studied using nitrogen adsorption and novel methods based on selective pore blocking via organosilane modification, and on the imaging of inverse platinum replica of ordered mesoporous structure. It was found that SBA-15 exhibits a relation between the pore size, pore volume and specific surface area which is significantly different from that for cylindrical or hexagonal pores, which suggests that the SBA-15 structure is m

A disordered mesoporous silica material has been prepared using polymerization of silicate anions surrounding surfactant micelles in the presence of organic salts. The local structure of the material has been investigated using a transmission electron micrograph image of platinum wire grown inside the mesopores. This micrograph imaging technique, developed in the present work, clarifies that the pore structure is a three-dimensional, disordered network of short wormlike channels while the channe

Low hydrothermal stability in hot water and aqueous solutions was a critical problem for many applications of the mesoporous molecular sieve MCM-41, compared with conventional zeolites such as Y and ZSM-5. The hydrothermal stability of MCM-41 has been found to improve remarkably by using various salts such as sodium chloride, potassium chloride, sodium acetate, and ethylenediaminetetraacetic acid tetrasodium salt during the hydrothermal crystallization process performed at 370 K. High-quality MC

Convenient and commercially viable synthesis conditions are described, providing efficient and reproducible control of pore connectivity and pore wall thickness for the synthesis of high quality SBA-15 mesoporous silica.

Hierarchical MFI zeolite was synthesized following a synthesis route using organic-inorganic hybrid surfactants; the resultant zeolite with mesoporous/microporous hierarchical structure exhibited remarkably high resistance to deactivation in catalytic activity of various reactions such as isomerization of 1,2,4-trimethylbenzene, cumene cracking, and esterification of benzyl alcohol with hexanoic acid, as compared with conventional MFI and mesoporous aluminosilicate MCM-41.

Powder X-ray diffraction, 29Si and 129Xe NMR spectroscopy of MCM-41 show that the long-range structural order and textural uniformity of the mesoporous molecular sieve are markedly improved due to a shift in the reaction equilibrium when acetic acid is repeatedly added during the conversion of sodium silicate and NMe3(C16H33)Cl to a MCM-41 phase.

Highly ordered mesoporous cerium oxides, composed of nanocrystalline pore walls and exhibiting high thermal stability even at 973 K, were synthesized using mesoporous silica templates with hexagonal p6mm and cubic Ia3d symmetries.

The cubic mesoporous silica molecular sieves MCM-48 have been obtained as an energetically favorable mesophase via a synthesis route using the surfactant mixtures between alkyltrimethylammonium bromides and polyoxyethylene alkyl ethers, with sodium silicate as the silica source. The MCM-48 mesophase was stable under the synthesis conditions for longer than a month, preventing a subsequent transformation to lamellar phases. Metal sources and salts could be added to the synthesis mixture during th