Synthesis of nanocrystals with variable high-index Pd facets through the controlled heteroepitaxial growth of trisoctahedral Au templates.
Synthesis of nanocrystals with variable high-index Pd facets through the controlled heteroepitaxial growth of trisoctahedral Au templates.
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DOI：
10.1021/ja107405x
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发表时间：
2010-12
影响因子：
15
通讯作者：
Yue Yu;Qingbo Zhang;Botao Liu;J. Lee
中科院分区：
文献类型：
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作者：
Yue Yu;Qingbo Zhang;Botao Liu;J. Lee
由高折射率面约束的贵金属纳米晶体（NC）的形状控制合成是当前的研究兴趣，因为产物具有显著改善NC在工业上重要的反应中的催化性能的潜力。本研究报告了一种通用的方法，用于合成由各种高指数Pd面包围的多面体NC。该方法是基于异质外延生长的Pd层上凹的三八面体（TOH）金NC种子的生长动力学仔细控制。可以以高产率形成具有三种不同类别的高折射率面的多面体Au@Pd NC，包括具有{hhl}面的凹形TOH NC、具有{hkl}面的凹形六八面体（HOH）NC和具有{hk 0}面的四面体（THH）NC。NC的米勒指数也是可修改的，并且我们使用THH NC作为示范性例子。通过甲酸电氧化的结构敏感反应评价了这些纳米碳的催化活性。结果表明，高折射率面一般比低折射率面更活跃。总之，基于凹面高折射率刻面Monopartite TOH NC模板和生长动力学的仔细控制的籽晶生长过程是用于合成具有高折射率刻面的贵金属NC的简单且有效的策略。它还在形状控制合成中提供表面结构的可定制性。
The shape-controlled synthesis of noble metal nanocrystals (NCs) bounded by high-index facets is a current research interest because the products have the potential of significantly improving the catalytic performance of NCs in industrially important reactions. This study reports a versatile method for synthesizing polyhedral NCs enclosed by a variety of high-index Pd facets. The method is based on the heteroepitaxial growth of Pd layers on concave trisoctahedral (TOH) gold NC seeds under careful control of the growth kinetics. Polyhedral Au@Pd NCs with three different classes of high-index facets, including concave TOH NCs with {hhl} facets, concave hexoctahedral (HOH) NCs with {hkl} facets, and tetrahexahedral (THH) NCs with {hk0} facets, can be formed in high yield. The Miller indices of NCs are also modifiable, and we have used the THH NCs as a demonstrative example. The catalytic activities of these NCs were evaluated by the structure-sensitive reaction of formic acid electro-oxidation. The results showed that the high-index facets are generally more active than the low-index facets. In summary, a seeded growth process based on concave high-index faceted monometallic TOH NC templates and careful control of the growth kinetics is a simple and effective strategy for the synthesis of noble metal NCs with high-index facets. It also offers tailorability of the surface structure in shape-controlled synthesis.