Examination of silver nanoparticle core-shell oleic acid bonding characteristics
article
Inorganic-organic core-shell nanoparticles are considered to be common building blocks for synthesis of multifunctional hybrid nanocomposites, which are promising materials for biomedical and catalytic application. Knowledge of the metal nanoparticle-ligand interaction mechanism is crucial for design strategy of such materials. In the present study silver-oleic acid capped nanoparticles are used as a model for mono- and bi-layer ligand chemisorption. FTIR spectroscopy, TGA and DTA data testify bidentate bonding carboxylic oxygen atoms to Ag nanoparticles and formation of secondary layer chemisorbed at the primary one at excess content of oleic acid . The pattern of activation energy versus mass loss of OA is used as fingerprint to determine the mechanism of chemisorption. Contrary to widely accepted Langmuir adsorption model, which predicts constant value of activation energy, Ea. the values calculated from experimental data varies significantly with a fraction of thermally desorbed material testifying increase in adsorption energy with surface coverage. Complex variation of Ea. with mass loss in presence of OA excess reflects contribution of several factors: increase in Ea. as OA molecules desorbed from sites with higher adsorption energy and simultaneous variation in chemical bond strength in a secondary layer.
Topics
TNO Identifier
844232
ISSN
01321447
Source
Bulletin of the Georgian National Academy of Sciences, 12(3), pp. 70-75.
Publisher
Georgian National Academy of Sciences
Collation
6 p.
Place of publication
Tbilisi, Georgia
Pages
70-75
Files
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