Control Over the Branched Structures of Platinum Nanocrystals for Electrocatalytic Applications
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- 作者：Liang Ma ; Chengming Wang ; Ming Gong ; Lingwen Liao ; Ran Long ; Jinguo Wang ; Di Wu ; Wei Zhong ; Moon J. Kim ; Yanxia Chen ; Yi Xie ; Yujie Xiong
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：November 27, 2012
- 年：2012
- 卷：6
- 期：11
- 页码：9797-9806
- 全文大小：663K
- 年卷期：v.6,no.11(November 27, 2012)
- ISSN：1936-086X
文摘
Structural control of branched nanocrystals allows tuning two parameters that are critical to their catalytic activity鈥攖he surface-to-volume ratio, and the number of atomic steps, ledges, and kinks on surface. In this work, we have developed a simple synthetic system that allows tailoring the numbers of branches in Pt nanocrystals by tuning the concentration of additional HCl. In the synthesis, HCl plays triple functions in tuning branched structures via oxidative etching: (i) the crystallinity of seeds and nanocrystals; (ii) the number of {111} or {100} faces provided for growth sites; (iii) the supply kinetics of freshly formed Pt atoms in solution. As a result, tunable Pt branched structures鈥攖ripods, tetrapods, hexapods, and octopods with identical chemical environment鈥攃an be rationally synthesized in a single system by simply altering the etching strength. The controllability in branched structures enables to reveal that their electrocatalytic performance can be optimized by constructing complex structures. Among various branched structures, Pt octopods exhibit particularly high activity in formic acid oxidation as compared with their counterparts and commercial Pt/C catalysts. It is anticipated that this work will open a door to design more complex nanostructures and to achieve specific functions for various applications.