Preparation of highly porous Al₂O₃ aerogel by one‐step solvent‐exchange and ambient‐pressure drying

Abstract

This work presents the preparation of alumina aerogel via sol-gel route utilizing ambient-pressure drying. A novel and efficient solvent-exchange process has been utilized as an alternative to conventional solvent-exchange processes by directly boiling the hydro-gel in solvent. High emphasis has been given in the selection of solvent based on polarity, boiling point, and specific gravity compared with water to facilitate efficient solvent-exchange and reuse of the solvent. The ambient-pressure-dried alumina aerogel was thermally treated at temperature from 300°C-1200°C to study the change in density, porosity, specific surface area, and microstructure along with crystalline properties. The ambient-pressure-dried alumina aerogel showed lower tapped density 0.108 g/cm 3 , specific surface area 519 m 2 /g, and total weight loss of 36.94% at 900°C. The degree of crystalline structure from amorphous was observed to increase with increase in thermal treatment temperature above 300°C, dominant above 700°C, whereas the transformation of bayerite γ-Al(OH) 3 to boehmite γ-AlO 2 H was observed at 150°C-300°C and to γ-Al 2 O 3 phase was observed at temperature of 300°C-1200°C. K E Y W O R D Saerogel/aerosol, drying, porous materials, sol-gel

Synthesis of TiO2‐doped carbon aerogel from sugarcane bagasse for high efficiency of photodegradation of methylene blue in the water

“…Meanwhile, porosities of TiO2/CA increased as elevating temperatures due to the decomposition of unstable components in the aerogels. [14] Particularly, TiO2/CA-800 sample obtained the highest porosity (98.88 %) and lowest density (0.021 g/cm 3 ), so it was chosen to investigate other factors in this research. Another reason that supports the choice of testing sample is that the sample was treated with 5 different temperatures of 400, 500, 600, 700, and 800 o C, respectively.…”

Facile Preparation of a Novel HfC Aerogel with Low Thermal Conductivity and Excellent Mechanical Properties

“…Aerogel has found extensive uses in many fields, such as thermal insulation [1,2], adsorption [3], catalysis [4], biological and medical applications [5], and energy storage and transformation [6]. Until now, oxide aerogels, such as SiO 2 , Al 2 O 3 , ZrO 2 , and TiO 2 [7][8][9][10], have consistently demonstrated outstanding thermal stability and exceptionally low thermal conductivity in the air atmosphere. However, due to the multifaceted applications of aerogels, the inherent instability of SiO 2 aerogels, particularly their susceptibility to structural collapse and densification at temperatures exceeding 800 • C, has posed a formidable challenge.…”