College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Jiangsu, 215123, China.
Department of Mechanical Engineering, Materials Science and Engineering Program, and Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
Nano Lett. 2015 Nov 11;15(11):7519-25. doi: 10.1021/acs.nanolett.5b04019. Epub 2015 Oct 26.
Despite the great success that has been accomplished on the controlled synthesis of Pd nanocrystals with various sizes and morphologies, an efficient approach to systematic production of well-defined Pd nanocrystals without seed-mediated approaches remains a significant challenge. In this work, we have developed an efficient synthetic method to directly produce Pd nanocrystals with a highly controllable feature. Three distinct Pd nanocrystals, namely, Pd nanosheets, Pd concave tetrahedra, and Pd tetrahedra, have been selectively prepared by simply introducing a small amount of ascorbic acid (AA) and/or water without the other synthesis conditions changed. We found that the combined use of AA and water is of importance for the successful production of the unique Pd nanosheets. Detailed catalytic investigations showed that all the obtained Pd nanocrystals exhibit higher activity in the formic acid electrooxidation and styrene hydrogenation with respect to the Pd black, and their activities are highly shape-dependent with Pd nanosheets demonstrating a higher activity than both the Pd concave tetrahedra and Pd tetrahedra, which is likely due to the simple yet important feature of ultrathin thickness of Pd nanosheets. The present work highlights the importance of structures in tuning the related properties of metallic nanocrystals.
尽管在控制合成具有各种尺寸和形貌的 Pd 纳米晶体方面取得了巨大的成功，但仍然需要一种有效的方法来系统地生产没有种子介导方法的定义明确的 Pd 纳米晶体。在这项工作中，我们开发了一种高效的合成方法，可以直接生产具有高度可控特征的 Pd 纳米晶体。通过简单地引入少量抗坏血酸 (AA) 和/或水，而不改变其他合成条件，可选择性地制备三种不同的 Pd 纳米晶体，即 Pd 纳米片、Pd 凹四面体和 Pd 四面体。我们发现，AA 和水的组合使用对于成功生产独特的 Pd 纳米片至关重要。详细的催化研究表明，与 Pd 黑相比，所有获得的 Pd 纳米晶体在甲酸电氧化和苯乙烯氢化反应中表现出更高的活性，并且它们的活性高度依赖于形状，Pd 纳米片的活性高于 Pd 凹四面体和 Pd 四面体，这可能是由于 Pd 纳米片具有超薄厚度的简单而重要的特征。本工作强调了结构在调节金属纳米晶体相关性质方面的重要性。
