Structural evolution of lamellar surfactant-silica hybrids upon calcination

A lamellar mesostructured silica was subjected to a progressive heat treatment in order to study its structural evolution and the characteristics of the resulting calcined powder. By combining informations from several physical methods, i.e. TG-DTA, XRD, TEM and nitrogen adsorption, it has been possible to evidence the formation of very small particles of silica at a temperature around 450 degreesC, exhibiting a very high value of aspect ratio, consequently to the template loss by combustion. By increasing the temperature above 530 degreesC, the dehydroxylation promotes a decrease in the surface area, followed by the sintering process at higher temperature, which nearly annihilate the surface area of the particles. (C) 2003 Elsevier Science Ltd. All rights reserved.