School of Materials, The University of Manchester , Manchester, M13 9PL, United Kingdom.
Nano Lett. 2014;14(4):1921-6. doi: 10.1021/nl4047448. Epub 2014 Mar 7.
Significant elemental segregation is shown to exist within individual hollow silver-gold (Ag-Au) bimetallic nanoparticles obtained from the galvanic reaction between Ag particles and AuCl4(-). Three-dimensional compositional mapping using energy dispersive X-ray (EDX) tomography within the scanning transmission electron microscope (STEM) reveals that nanoparticle surface segregation inverts from Au-rich to Ag-rich as Au content increases. Maximum Au surface coverage was observed for nanoparticles with approximately 25 atom % Au, which correlates to the optimal catalytic performance in a three-component coupling reaction among cyclohexane carboxyaldehyde, piperidine, and phenylacetylene.
从 Ag 颗粒和 AuCl4(-)之间的电化学反应中获得的单个中空银金（Ag-Au）双金属纳米粒子中显示出明显的元素偏析。使用扫描透射电子显微镜（STEM）内的能量色散 X 射线（EDX）层析成像进行的三维成分映射表明，随着 Au 含量的增加，纳米粒子表面的偏析从富 Au 转变为富 Ag。在 Au 含量约为 25 原子%的纳米粒子中观察到最大的 Au 表面覆盖率，这与环己烷羧酸醛、哌啶和苯乙炔之间的三组分偶联反应的最佳催化性能相关。
