Preparation and microstructure of sol-gel derived silver-doped silica

2007-08-01
Akkopru, Betul
Durucan, Caner
Silver-doped silica was prepared by hydrolysis and condensation of tetraethyl orthosilicate (TEOS, Si(OC2H5)(4)) in the presence of a silver nitrate (AgNO3) solution by two different synthesis methods. In the first synthesis route, sol-gel mixtures were prepared using an acid catalyst. In the second synthesis route, silver-doped silica gels were formed by two-step acid/base catalysis. For the same concentration of silver dopant [AgNO3]/[TEOS] = 0.015 acid-catalyzed sol-gel formed a microporous silica with an average pore size of < 25 angstrom whereas the two-step catalyzed silica had an average pore size of 250 angstrom and exhibited a mesoporous structure when fully dried. The differences in the pore size affected the silver particle formation mechanism and post-calcination silver particle size. After calcination at 800 degrees C for 2 h the acid-catalyzed silica contained metallic silver particles size with an average particle size of 24 +/- 2 nm whereas two-step catalyzed silica with the same concentration of [AgNO3]/[TEOS] = 0.015 contained silver nanoparticles with an average size of approximately 32 +/- 2 nm. Mechanisms for silver particle formation and for silica matrix crystallization with respect to the processing route and calcination temperature are discussed.

Citation Formats
B. Akkopru and C. Durucan, “Preparation and microstructure of sol-gel derived silver-doped silica,” JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY, vol. 43, no. 2, pp. 227–236, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46666.