Fabrication and Characterization of Porous Silica Monolith by Sintering Silica Nanoparticles

Abstract

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 SiO 2 -poly (vinyl alcohol) (PVA) nanocomposite at 600˚C -1100˚C. The sintering behavior was examined by means of Raman spectroscopy and a porosimetry. The PVA of the SiO 2 -PVA nanocomposite was combusted below 600˚C, subsequently the silica nanoparticles of the nanocomposite were sintered above 900˚C. The Raman spectroscopy suggested that amorphous structure of the porous silica monolith obtained above 1000˚C 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 m 2 ·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.