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.
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY

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Citation Formats
B. Akkopru and C. Durucan, “Preparation and microstructure of sol-gel derived silver-doped silica,” JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY, pp. 227–236, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46666.