2020, №1

сс. 92-102

Effect of «Water-Precursor» Ratio on the Structural Characteristics of Aluminum Oxide Aerogels

2020, №1

сс. 92-102

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N.V. Menshutina, A.E. Lebedev, I.I. Khudeev

Key words: aerogel, aluminum oxide, metal oxides, supercritical drying, supercritical carbon dioxide, specific surface area, porosity

Alumina aerogels were obtained using sol-gel synthesis and subsequent supercritical
drying. Sol-gel synthesis was carried out by adding epichlorohydrin to aluminum chloride
dissolved in water and ethanol. Supercritical drying (SCD) of gels was carried out in
supercritical carbon dioxide at 40 °C and 12,0 MPa for 8 hours. The structural
characteristics of aerogels were studied by nitrogen porometry, helium pycnometry
and scanning electron microscopy. The resulting materials have high specific surface
area (up to 764 m2/g) and porosity (up to 96,2 %, pore volume up to 4,9 cm3/g) and
low density (below 0,066 g/cm3). It was found that the structural characteristics of
aerogels can be controlled by changing the «water : precursor» ratio. In particular, an
increase in this ratio leads to an increase in the specific surface area and pore volume.

doi:10.1134/S1990793120070222