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Rigid Nanoscopic Containers for Highly Dispersed, Stable Metal and Bimetal Nanoparticles with Both Size and Site Control
Author(s) -
Wang Chunlei,
Zhu Guangshan,
Li Jian,
Cai Xiaohui,
Wei Yuhong,
Zhang Daliang,
Qiu Shilun
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500390
Subject(s) - bimetal , mesoporous material , mesoporous silica , nanoparticle , materials science , dendrimer , mesoporous organosilica , chemical engineering , metal , nanotechnology , polymer chemistry , chemistry , catalysis , organic chemistry , composite material , metallurgy , engineering
We demonstrate a novel strategy for the preparation of mesoporous silica‐supported, highly dispersed, stable metal and bimetal nanoparticles with both size and site control. The supporting mesoporous silica, functionalized by polyaminoamine (PAMAM) dendrimers, is prepared by repeated Michael addition with methyl acrylates (MA) and amidation reaction with ethylenediamine (EDA), by using aminopropyl‐functionalized mesoporous silica as the starting material. The encapsulation of metal nanoparticles within the dendrimer‐propagated mesoporous silica is achieved by the chemical reduction of metal‐salt‐impregnated dendrimer–mesoporous silica by using aqueous hydrazine. The site control of the metal or bimetal nanoparticles is accomplished by the localization of inter‐ or intradendrimeric nanoparticles within the mesoporous silica tunnels. The size of the encapsulated nanoparticles is controlled by their confinement to the nanocavity of the dendrimer and the mesopore. For Cu and Pd, particles locate at the lining of mesoporous tunnels, and have diameters of less than 2.0 nm. For Pd/Pt, particles locate at the middle of mesoporous tunnels and have diameters in the range of 2.0–4.2 nm. The Pd and Pd/Pt nanoparticles are very stable in air, whereas the Cu nanoparticles are stable only in an inert atmosphere.