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The impact of Si/Al ratio on properties of aluminosilicate aerogels. / Shalygin, Anton S.; Kozhevnikov, Ivan V.; Gerasimov, Evgeny Yu и др.
в: Microporous and Mesoporous Materials, Том 251, 10.2017, стр. 105-113.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - The impact of Si/Al ratio on properties of aluminosilicate aerogels
AU - Shalygin, Anton S.
AU - Kozhevnikov, Ivan V.
AU - Gerasimov, Evgeny Yu
AU - Andreev, Andrey S.
AU - Lapina, Olga B.
AU - Martyanov, Oleg N.
PY - 2017/10
Y1 - 2017/10
N2 - The Si/Al ratio is a key parameter of acid-base, structural, textural and, consequently, catalytic properties of amorphous crystalline (micro- and mesoporous) aluminosilicates. The changes of structural and textural characteristics of Al-Si aerogels with gradual increase of aluminum content are investigated. Aerogels were prepared via sol-gel method using prehydrolysed tetraethoxysilane and aluminium isopropoxide stabilized by acetylacetone. The gelation of the obtained sols took place in the presence of ammonia with the following drying in supercritical isopropanol. It was shown all aluminum reacts with prehydrolyzed tetraethoxysilane forming spherical particles in case the content of Al in the samples is less than 20 mol %. Aluminum drives the increase of interparticle coupling leading to the particle agglomeration, which is associated with the increase of the particle size and decrease of specific surface area and pore volume. For the samples with the aluminum content of >50 mol % the formation of pseudoboehmite plate-like particles is observed. The pseudoboehmite particles prevent the sintering of SiO2 particles that leads to the increase of the aerogel specific surface area and pore volume. In case the high aluminum content (>80 mol %) the silica particles serve as a connector between boehmite plates. The ratio between Brønsted and Lewis acid sites decreases gradually with the increase of aluminum content of the aluminosilicate aerogels.
AB - The Si/Al ratio is a key parameter of acid-base, structural, textural and, consequently, catalytic properties of amorphous crystalline (micro- and mesoporous) aluminosilicates. The changes of structural and textural characteristics of Al-Si aerogels with gradual increase of aluminum content are investigated. Aerogels were prepared via sol-gel method using prehydrolysed tetraethoxysilane and aluminium isopropoxide stabilized by acetylacetone. The gelation of the obtained sols took place in the presence of ammonia with the following drying in supercritical isopropanol. It was shown all aluminum reacts with prehydrolyzed tetraethoxysilane forming spherical particles in case the content of Al in the samples is less than 20 mol %. Aluminum drives the increase of interparticle coupling leading to the particle agglomeration, which is associated with the increase of the particle size and decrease of specific surface area and pore volume. For the samples with the aluminum content of >50 mol % the formation of pseudoboehmite plate-like particles is observed. The pseudoboehmite particles prevent the sintering of SiO2 particles that leads to the increase of the aerogel specific surface area and pore volume. In case the high aluminum content (>80 mol %) the silica particles serve as a connector between boehmite plates. The ratio between Brønsted and Lewis acid sites decreases gradually with the increase of aluminum content of the aluminosilicate aerogels.
KW - Aerogels
KW - Aluminosilicate
KW - Si/Al ratio
KW - Sol-gel method
KW - Supercritical drying
KW - POROSITY
KW - SOL-GEL METHOD
KW - SILICA-ALUMINA
KW - SURFACE-AREA
KW - MULLITE
KW - NMR
KW - XEROGELS
KW - SITES
KW - CATALYSTS
KW - ACIDITY
UR - http://www.scopus.com/inward/record.url?scp=85020312949&partnerID=8YFLogxK
U2 - 10.1016/j.micromeso.2017.05.053
DO - 10.1016/j.micromeso.2017.05.053
M3 - Article
AN - SCOPUS:85020312949
VL - 251
SP - 105
EP - 113
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
SN - 1387-1811
ER -
ID: 10187448