...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Crystal growth & design >Crystal structures and growth mechanisms of icosahedral Au@Ag core-shell and Au/Ag twin nanocrystals prepared by PVP-assisted N, N-dimethylformamide reduction
【24h】

Crystal structures and growth mechanisms of icosahedral Au@Ag core-shell and Au/Ag twin nanocrystals prepared by PVP-assisted N, N-dimethylformamide reduction

机译：PVP辅助N，N-二甲基甲酰胺还原制备二十面体Au @ Ag核壳和Au / Ag双纳米晶体的晶体结构和生长机理

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Icosahedral Au@Ag core-shell nanocrystals have been prepared using a two-step reduction method. In the first step, icosahedral Au core seeds were prepared by reducing HAuCl4·4H2O in tetraethylene glycol (TEG) under microwave (MW) heating in the presence of polyvinylpyrrolidone (PVP) as a polymer surfactant. In the second step, Ag shells were overgrown on icosahedral Au seeds in N,N-dimethylformamide (DMF) in the presence of PVP under oil-bath heating for 3 h or MW heating for 10 min. Crystal structures of products were characterized using TEM, TEM-EDS, and SEM. Under oil-bath heating, Au@Ag icosahedral nanocrystals nearly fully covered by Ag shells were prepared, whereas those partially covered by tetrahedral units of Ag shells were formed under MW heating. On the basis of these findings, it was concluded that icosahedral Au@Ag core-shell particles are formed through stepwise growth of tetrahedral units, as observed in the crystal growth of monometallic icosahedral Ag crystals in DMF. There were minor Au/Ag twin products under fast MW heating where icosahedral Ag nanocrystals are grown up outside of icosahedral Au cores sharing one decahedral Au core or one {111} facet of a tetrahedral unit. These findings provide new information on the stepwise growth mechanism of nanocrystals in the presence of icosahedral Au seeds in DMF.
机译：二十面体Au @ Ag核壳纳米晶体已使用两步还原法制备。第一步，在聚乙烯吡咯烷酮（PVP）作为聚合物表面活性剂的存在下，在微波（MW）加热下，通过在四甘醇（TEG）中还原HAuCl4·4H2O，制备二十面体Au核心种子。第二步，在油浴加热3 h或MW加热10 min的情况下，在PVP存在下，在N，N-二甲基甲酰胺（DMF）中的二十面体Au种子上长满Ag壳。使用TEM，TEM-EDS和SEM表征产物的晶体结构。在油浴加热下，制备了几乎完全被Ag壳覆盖的Au @ Ag二十面体纳米晶体，而在MW加热下形成了被Ag壳的四面体单元部分覆盖的Au @ Ag二十面体纳米晶体。基于这些发现，可以得出结论，二十面体Au @ Ag核壳颗粒是通过逐步生长四面体单元形成的，正如在DMF中单金属二十面体Ag晶体的生长中所观察到的。在快速MW加热下，有少量Au / Ag孪晶产物，其中二十面体Ag纳米晶体生长在二十面体Au核之外，共享一个十面体Au核或一个四面体单元的{111}晶面。这些发现提供了在DMF中存在二十面体Au种子的情况下纳米晶体逐步生长机制的新信息。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号