Catalyst for Tetraethyoxysilane under Ambient Pressure Synthesis of Silica Aerogels

Nano-porous material SiO2 aerogels were made by a sol-gel technique using tetraethyoxysilane,under ambient and catalyzed by HF or HF/NH4OH. The results show that the hydrofluoric acid(HF) is a effective catalyst for the gel formation.The more effective catalyst(HF/NH4OH) on the synthesis and properties of silica aerogels was investigted.The microstructure and properties of the two type silica aerogels were tested by TG-DTA,BET,FTIR,XRD and lase granularity analyzer techniques.XRD shows that the two type silica aerogels both were non-crystalline silica with nano-sized structure.At the same time,Lase granularity analyzer shows that the average particle size of silica aerogels is less than 20μm.It is a mesoporous structure.