Synthesis of Mesoporous Silica Materials via Nonsurfactant Templated Sol-Gel Route by Using Mixture of Organic Compounds as Template

摘要

Mesoporous silica materials have been successfully prepared by employing a mixture of #beta#-cyclodextrin and urea as a template in a HCl-catalyzed sol-gel process, followed by extraction with water. The obtained materials are characterized by nitrogen adsorption-desorption measurements, powder X-ray diffraction patterns and transmis-sion electron microscopy. The changes of the pore parameters depend on both the weight ratio of #beta#-cyclodextrin and urea and the template content in the final silica composite. The effects of the mixture as template (or pore-forming agent) on the physicochemical properties of the two synthesized systems, with different weight ratio and same template content, as well as varied template content and fixed weight ratio, were investigated in this paper. The results show that the hydrogen bonding interactions bvetween #beta#-cyclodextrin and urea molecules or urea aggregates, the urea-holding #beta#-cyclodextrin molecules themselves as well as inorganic species are the driving force in the formation of mesoporous silica materials.