科研之友
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摘要
The transformation from Ag templates to Au-Ag nanoshells via galvanic replacement reaction with HAuCl4 was systematically studied in an organic medium in the presence of oleylamine. Decahedral (similar to 43 nm in size) and triangular prism (similar to 53 nm in edge length) Ag templates transformed into equiaxed and triangular prismatic Au-Ag nanoshells, respectively. The first step involved structural and morphological changes from Ag templates to Au-Ag nanoshells with an interior cavity. In the second step, the growth of the shells continued through the deposition of Au. The shell thickness increased from similar to 5 to similar to 10 nm for the equiaxed Au-Ag nanoshells (similar to 39-nm interior cavity) and similar to 5 to similar to 8 nm for the triangular prismatic Au-Ag nanoshells (similar to 52-nm interior edge length). Oleylamine not only served as a surfactant but also removed AgCl precipitates and reduced HAuCl4. For the nanoshells derived from the similar to 20-nm Ag decahedrons, further reaction in excess HAuCl4 collapsed the nanoshells into Au-rich solid fragments. However, the nanoshells derived from the similar to 43-nm Ag decahedrons, the nanoshell structure not only persisted in excess HAuCl4, but its shell thickness also increased. The size-dependent transformation of these nanoshells is discussed.
- 出版日期2012-10
