Performance regulation of silica aerogel powder synthesized by a two-step Sol-gel process with a fast ambient pressure drying route

• Silica aerogel powder was successfully synthesized through two-step Sol-gel reaction and a timesaving ambient pressure drying route. • The silica aerogel powder can be pressed into transparent sheets. • The silica aerogel powder features with a high BET surface area of 769.86 m 2 /g as well as a big hydrophobic angle of 149.0 °. • By changing the synthesis parameters, thermal conductivity can be adjusted to 0.053 W/mK and BET surface area can be 769.86 m 2 /g. • The silica aerogel powder exhibits a pretty low thermal conductivity of 0.053 W/m/K and a small density of 0.212 g/cm 3 . This paper proposed a timesaving route for preparing silica aerogel powder with TEOS as a precursor. Thermal insulating super hydrophobic silica aerogel powder was synthesized by combining two-step Sol-gel reaction with a fast ambient pressure drying process. Silica Sol-gel was formed after catalytic reaction by oxalic acid and NH 4 OH, and then turned to be hydrophobic aerogel through further surface modification (only three hours with no solvent exchange process) and drying process. By optimizing every tiny trace of synthetic component, the obtained silica aerogel powder exhibits excellent properties, such as low apparent density (0.212 g/cm 3 ) and thermal conductivity (0.053 W/mK), as well as high BET surface area (769.86 m 2 /g) and water contact angle (149.0 °). This work presents a timesaving method for synthesizing thermal insulating hydrophobic silica aerogel powder.