Single-Crystalline Octahedral Au–Ag Nanoframes

Xun Hong , Dingsheng Wang , Shuangfei Cai ,Hongpan Rong , and Yadong Li *

Department of Chemistry and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China

J. Am. Chem. Soc., Article ASAP

DOI: 10.1021/ja3076132

Publication Date (Web): October 22, 2012

Copyright © 2012 American Chemical Society

We report the formation of single-crystalline octahedral Au–Ag nanoframes by a modified galvanic replacement reaction. Upon sequential addition of AgNO₃, CuCl, and HAuCl₄ to octadecylamine solution, truncated polyhedral silver nanoparticles formed first and then changed into octahedral Au–Ag nanoframes, without requiring a conventional Ag removal step with additional oxidation etchant. The nanoframes have 12 sides, and all of the eight {111} faces are empty. The side grows along the [110] direction, and the diameter is less than 10 nm. The selective gold deposition on the high-energy (110) surface, the diffusion, and the selective redeposition of Au and Ag atoms are the key reasons for the formation of octahedral nanoframes.