Fabrication and Characterization of Porous Silica Monolith by Sintering Silica Nanoparticles

This paper aims to fabricate over centimeter size of porous silica monolith having meso-pores with large surface area. A precursor of porous silica monolith was obtained by sintering a monolithic SiO2-poly (vinyl alcohol) (PVA) nanocomposite at 600oC-1100oC. The sintering behavior was examined by means of Raman spectroscopy and a porosimetry. The PVA of the SiO2-PVA nanocomposite was combusted below 600oC, subsequently the silica nanoparticles of the nanocomposite were sintered above 900oC. The Raman spectroscopy suggested that amorphous structure of the porous silica monolith obtained above 1000oC was similar to that of a silica glass. The BET surface area and pore radius of the porous silica monolith decreased with increasing sintering temperature. These values were tailored in the range of ca. 0-291 m2.g-1 and 5-25 nm, respectively, by controlling the sintering temperature and time. The fabricated porous-silica monolith was translucent or opaque porous-silica depending on the pore size.