Rapid and microthermal synthesis of centimetre-sized mesoporous silica aerogel sphere by using DMSO-CO2 as solvent

• Centimetre-sized silica aerogel spheres were prepared via sol-gel process.
• Samples were prepared using DMSO-CO2 solvent for one-step aging/solvent exchange at 2 MPa.
• The silica aerogel sphere with satisfactory performance is manufactured at 4 °C.
• S-4 has a typical three-dimensional porous structure with pore diameter about 25.4 nm.
• S-4 has minimum density 0.12 g/cm3 and maximum specific surface area 1078 m2/g.

Centimetre-sized mesoporous silica aerogel sphere (SAS) was synthesized via sol-gel technology by one-step aging/solvent exchange at 2 MPa and using DMSO-CO2 as solvent. DMSO-CO2 solvent was obtained at 7.5 MPa with CO2 fluid in autoclave. The influence of an important factor, temperature, on the SASs’ performance is briefly discussed and the optimal temperature is 4 °C. Low temperature is an effective way to overcome the fragility and shrinkage of SASs. Investigations by bulk density, FTIR, BET and FE-SEM indicate that the SAS has a typical three-dimensional porous structure with pore diameter about 25.4 nm, minimum bulk density 0.12 g/cm3 and specific surface area as high as 1078 m2/g. Due to the good properties of mesoporous, the SAS could be a promising candidate of filling materials.