Overpotential-dependent shape evolution of gold nanocrystals grown in a deep eutectic solvent

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• 作者：Lu Wei ; Bangan Lu ; Mingjun Sun ; Na Tian ; Zhiyou Zhou ; Binbin Xu…
• 关键词：gold nanocrystals ; shape evolution ; electrochemical synthesis ; deep eutectic solvent ; glucose electrooxidation
• 刊名：Nano Research
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：9
• 期：11
• 页码：3547-3557
• 全文大小：1,858 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chinese Library of Science
  Chemistry
  Nanotechnology
  
• 出版者：Tsinghua University Press, co-published with Springer-Verlag GmbH
• ISSN：1998-0000
• 卷排序：9

文摘

This paper reports an overpotential-dependent shape evolution of gold nanocrystals (Au NCs) in a choline chloride-urea (ChCl-urea) based deep eutectic solvent (DES). It was found that the growth overpotentials play a key role in tuning the shape of Au NCs. The shape evolution of Au NCs successively from concave rhombic dodecahedra (RD) to concave cubes, octopods, cuboctahedral boxes, and finally, to hollow octahedra (OH) was achieved by carefully controlling the growth overpotentials in the range from –0.50 to –0.95 V (vs. Pt quasi-reference electrode). In addition, the presence of urea was important in the shape evolution of Au NCs. The surface structure of the as-prepared Au NCs was comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical studies. It was demonstrated that the electrocatalytic activity of the as-prepared Au NCs for D-glucose electrooxidation was sensitively dependent on their morphologies. The results illustrated that the dehydrogenated glucose adsorbed on concave RD and concave cubic Au NCs was preferentially transformed to gluconolactone at low electrode potentials. Subsequent gluconolactone oxidation occurred favorably on octopods with {111}-truncated arms and hollow OH at high electrode potential. This study opens up a new approach to develop the surface-structurecontrolled growth of Au NCs by combining DES with electrochemical techniques. In addition, it is significant for the tuning of the electrocatalytic properties of NCs.