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          Institute: Fritz-Haber-Institut     Collection: Inorganic Chemistry     Display Documents



  history
ID: 293461.0, Fritz-Haber-Institut / Inorganic Chemistry
Toward Monodispersed Silver Nanoparticles with Unusual Thermal Stability
Authors:Sun, Junming; Ma, Ding; Zhang, He; Liu, Xiumei; Han, Xiuwen; Bao, Xinhe; Weinberg, Gisela; Pfänder, Norbert; Su, Dang Sheng
Language:English
Research Context:Electron microscopic investigations on the important catalytic systems
Date of Publication (YYYY-MM-DD):2006
Title of Journal:Journal of the American Chemical Society
Journal Abbrev.:JACS
Volume:128
Issue / Number:49
Start Page:15756
End Page:15764
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:A novel in situ autoreduction route has been developed, by which monodispersed silver nanoparticles with tunable sizes could be easily fabricated on silica-based materials, especially inside the channels of mesoporous silica (MPS). 13C CP/MAS NMR spectroscopy was employed to monitor the whole assembly process. It was demonstrated that the amino groups of APTS (aminopropyltriethoxyl silane)-modified MPS can be used to anchor formaldehyde to form novel reducing species (NHCH2OH), on which Ag(NH3)2NO3 could be in situ reduced. Monodispersed silver nanoparticles were thus obtained. In situ XRD and in situ TEM experiments were used to investigate and compare the thermal stabilities of silver nanoparticles on the external surface of silica gels (unconfined) and those located inside the channels of SBA-15 (confined). It was observed that unconfined silver nanoparticles tended to agglomerate at low temperatures (i.e., lower than 773 K). The aggregation of silver nanoparticles became more serious at 773 K. However, for those confined silver nanoparticles, no coarsening process was observed at 773 K, much higher than its Tammann temperature (i.e., 617 K). Only when the treating temperature was higher than 873 K could the agglomeration of those confined silver nanoparticles happen with time-varying via the Ostwald ripening process. The confinement of mesopores played a key role in improving the thermal stabilities of silver nanoparticles (stable up to 773 K without any observable coarsening), which is essential to the further investigations on their chemical (e.g., catalytic) properties.
External Publication Status:published
Document Type:Article
Communicated by:Robert Schlögl
Affiliations:Fritz-Haber-Institut/Inorganic Chemistry/Microstructure
External Affiliations:State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
Identifiers:URL:http://dx.doi.org/10.1021/ja064884j [only subscribers]
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