Synthesis of Dispersible Pd@CeO2 Core-Shell Nanostructures by Self-Assembly
Synthesis of Dispersible Pd@CeO2 Core-Shell Nanostructures by Self-Assembly
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DOI：
10.1021/ja909131k
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发表时间：
2010-02-03
影响因子：
15
通讯作者：
Fornasiero, Paolo
中科院分区：
文献类型：
--
作者：
Cargnello, Matteo;Wieder, Noah L.;Fornasiero, Paolo
描述了一种用于制备Pd@CeO2核-壳纳米结构的方法，所述核-壳纳米结构易于分散在常见的有机溶剂中。该方法涉及由单层的11-mercaptowendecanoic酸（MUA）的保护的Pd纳米粒子的合成。纳米颗粒表面上的羧基用于引导铈（IV）醇盐在金属颗粒周围的自组装，然后通过受控水解形成CeO 2。通过不同的技术手段，特别是通过电子显微镜的纳米结构的表征，使我们能够证明核-壳系统的性质，与CeO 2纳米晶体形成壳周围的MUA保护的Pd核。最后，使用这些纳米结构作为灵活的前体的非均相催化剂的制备的一个例子是通过调查的Pd@CeO2/Al 2 O3纳米复合材料对CO氧化，水煤气变换（WGS），甲醇蒸汽重整反应的反应性。与CO吸附数据一起，这些观察结果表明Pd相在纳米复合材料中的可访问性。
A methodology is described for the preparation of Pd @ CeO2 core-shell nanostructures that are easily dispersible in common organic solvents. The method involves the synthesis of Pd nanoparticles protected by a monolayer of 11-mercaptoundecanoic acid (MUA). The carboxylic groups on the nanoparticle surfaces are used to direct the self-assembly of a cerium(IV) alkoxide around the metal particles, followed by the controlled hydrolysis to form CeO2. The characterization of the nanostructures by means of different techniques, in particular by electron microscopy, allowed us to demonstrate the nature of core-shell systems, with CeO2 nanocrystals forming a shell around the MUA-protected Pd core. Finally, an example of the use of these nanostructures as flexible precursors for the preparation of heterogeneous catalysts is reported by investigating the reactivity of Pd@CeO2/Al2O3 nanocomposites toward CO oxidation, water-gas shift (WGS), and methanol steam reforming reactions. Together with CO adsorption data, these observations suggest the accessibility of the Pd phase in the nanocomposites.