Microporous Silica Particles Prepared by the Salt-Catalytic Sol-Gel Process with Extremely Low Content of Water

Microporous silica was synthesized by the salt catalytic sol-gel process with extremely low content of water to tetramethoxysilane. Silica particles were precipitated even when the extent of hydrolysis was very low, since ammonium carbonate as a salt catalyst made the polycondensation faster than an acid catalyst. Microporous silica with a high surface area (680 m² g^–1) was obtained by combustion of methoxy groups at 450°C. The methoxy groups can be removed by the post-hydrolysis before heating. A high specific surface area (>750 m²g^–1) of microporous silica was obtained with pore diameter between 1.2 and 2.0 nm.