Abstract

Noble-metal nanocrystals with structural features such as high-index facets and twin defects on the surface are desirable for various catalytic applications. Here we report an aqueous route to the facile synthesis of Pd–M (M = Pd, Pt, and Au) decahedra covered with concave facets by controlling the deposition and diffusion of M atoms on Pd decahedral seeds. Our mechanistic studies indicate that the preferential deposition of M atoms on the twin boundaries of Pd decahedral seeds under limited surface diffusion is instrumental to their evolution into decahedra enclosed by concave facets. Due to the presence of high-index facets and twin boundaries on the surface, the Pd concave decahedra show enhanced catalytic activity towards formic acid oxidation. The present work not only offers a general route to the facile synthesis of decahedral nanocrystals with concave facets but also provides an additional knob for enhancing the catalytic performance of noble-metal nanocrystals.

中文翻译：

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具有凹面的Pd–M（M = Pd，Pt和Au）十面体的水性合成

摘要

对于各种催化应用而言，具有诸如高折射率小面和表面上的双缺陷的结构特征的贵金属纳米晶体是期望的。在这里，我们报告了通过控制Pd十面体晶种上M原子的沉积和扩散，方便地合成Pd–M（M = Pd，Pt和Au）十面体的方法，该表面覆盖有凹面。我们的机理研究表明，在有限的表面扩散条件下，M原子优先沉积在Pd十面体种子的孪晶边界上，这有助于它们演化成由凹面包围的十面体。由于表面上存在高折射率小平面和孪晶边界，Pd凹面十面体显示出增强的对甲酸氧化的催化活性。