Pore size-controlled synthesis and characterization of nanostructured silica particles.

Silica nano-materials with meso- and macroporosity are of great interest due to their variety of potential applications. For the application as a catalytic supporter, nanostructured spherical silica particles having both mesopores and macropores were prepared by using an aerosol templating method with colloidal mixtures of polystyrene latex (PSL) particles and silica nanoparticles. The as-prepared particles showed bimodal size distribution consisting of mesopores ranging 2-20 nm and macropores ranging 60-160 nm. As the PSL size decreased, mesopore size increased due to a reduction in packing rates of primary SiO(2) nanoparticles composing the walls of nanostructured porous particles. With an increment of the weight ratio of PSL/SiO(2), mesopores size increased but mesopore volume decreased due to the broken structure of particles and reduction in packing rates. Mesopores disappeared when the furnace temperature was 900 degrees C. The residuals of organic template were detected when furnace temperature and flow rate of carrier gas were below 600 degrees C and above 3 l/min, respectively.