Тип публикации: статья из журнала
Год издания: 2014
Идентификатор DOI: 10.1134/S1087659614010118
Ключевые слова: mesostructured mesoporous silicates, template synthesis, MCM-41, hydrothermal stability, X-ray diffraction, method of continuous electron density function, N-2 adsorption, N2 adsorption
Аннотация: Changes in the mesostructure and hydrothermal stability of the MCM-41 silicate material, depending on the synthesis conditions have been investigated. The mesostructure was characterized by the X-ray structural analysis, adsorption surface measurements, and hydrothermal stability. Changes in the synthesis conditions consisted in chПоказать полностьюanging the reaction solution basicity using ammonia and alkali and replacing the mother liquor used in hydrothermal treatment by water, as well as salt and alcohol-ammonia solutions. The increase of the pore diameter is caused, as a rule, by the water osmotic pressure. Moreover, if the silica polycondensation is slowed or sterically hindered, the pores acquire a hexagonal shape or, under conditions promoting polycondensation, a cylindrical one. Predominance of the hexagonal shape over the cylindrical one points to the reduced hydrothermal stability of the material. Pore wall consists of two-layer silica pack with thickness of 0.08-0.10 nm. Ammonia applying, as reaction medium basicity factor, provides maximal silica polymerisation rate and hight hydrothermal stability of the material.
Журнал: GLASS PHYSICS AND CHEMISTRY
Выпуск журнала: Vol. 40, Is. 1
Номера страниц: 49-59
ISSN журнала: 10876596
Место издания: NEW YORK
Издатель: MAIK NAUKA/INTERPERIODICA/SPRINGER