Larger scale syntheses of surfactant-templated nanoporous silica spherical particles by the Stober method

The larger scale production of nanoporous silica spherical particles was investigated. The particles formed from aqueous solution containing cetyltrimethylammonium chloride, tetraethoxysilane (TEOS), methanol, and ammonia at room temperature and subsequent calcination in air at 550 degrees C led the transformation of the particles to be nanoporous with retaining the original particle morphology. The increase in the TEOS amount in the starting solution was effective for larger scale synthesis without significant loss of particle size distribution. Average particle size varied from 50 nm to 320 urn and the BET surface area varied I rom 240 to 850 m(2) g(-1). Maximum product weight achieved was ca. 1 g from 100 g of starting solution; the value is one order greater than those obtained by previously reported starting solutions, where TEOS amount is much smaller. The particle size (to 1721 nm) and surface area (up to 1020 m(2) g(-1)) were changed by the surfactant amount in the starting solutions.