Synthesis and Characterization of Core−Shell FePt@Ti-Containing Silica Spherical Nanocomposite as a Catalyst Carrier for Liquid-Phase Reactions

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• 作者：Kohsuke Mori ; Kohei Sugihara ; Yuichi Kondo ; Tetsuya Takeuchi ; Shotaro Morimoto ; Hiromi Yamashita
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：October 23, 2008
• 年：2008
• 卷：112
• 期：42
• 页码：16478-16483
• 全文大小：197K
• 年卷期：v.112,no.42(October 23, 2008)
• ISSN：1932-7455

文摘

Colloidal FePt nanoparticles stabilized by oleic acid and oleylamine were modified through a ligand exchange with (3-mercaptpropyl)-trimethoxysilane. The particles were subsequently treated using the so-gel route with tetraethyl orthosilicate and tetrapropylorthotitanate. A new nanocomposite (FePt@Ti-SiO₂) was characterized by means of X-ray diffraction, IR, transmission electron microscopy, superconducting quantum interface device, and X-ray absorption fine structure measurements. The face-centered cubic FePt NPs with a mean diameter of ca. 6 nm were encapsulated in the Ti-SiO₂ thick shell, which exhibited superparamagnetic behavior at 300 K with zero remanence and coercivity. The Ti-oxide moiety was proven to exist in the isolated and tetrahedral form. The FePt@Ti-SiO₂ served as an efficient nanocatalyst for the liquid-phase selective epoxidation using hydrogen peroxide (H₂O₂). Recovery from the reaction mixture was readily attained by applying an external permanent magnet, and the spent catalyst could be recycled without any appreciable loss in activity.