Morphology and dispersivity modulation of hollow microporous spheres synthesized by a hard template route

Uniform hollow microporous silica spheres (HMS) have been synthesized in an easy route using polystyrene spheres (PS) and cetyltrimethylammonium bromide (CTAB) as co-templates at room temperature in concentrated aqueous ammonia. The hexagonally ordered pore channels are formed on the shell of the HMS. Effects of various processing parameters such as the tetraethyl orthosilicate (TEOS) adding rate, the amount of aqueous ammonia and ultrasonic treatment, on the dispersivity and morphology, were investigated. The slow syringing addition of TEOS favors the formation of highly dispersed hollow spheres with a certain and uniform shell thickness. More aqueous ammonia and proper time of ultrasonic are helpful to the synthesis of uniform hollow silica spheres with good dispersivity. The morphology, dispersivity and micropore structure of as-synthesized HMS were characterized using X-ray diffraction, N₂ sorption isotherms, scanning electron microscope and transmission electron microscope.