Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Aoba-ku, Sendai, Japan.
J Colloid Interface Sci. 2012 Jun 1;375(1):78-87. doi: 10.1016/j.jcis.2012.02.030. Epub 2012 Mar 3.
Gold-platinum-silver (Au-Pt-Ag) ion mixtures produced nanoparticle alloys with an average particle size of 5 nm after co-reduction of metal ions by femtosecond laser irradiation of aqueous solutions in the presence of ammonia and polyvinylpyrrolidone, which was used as a stabilizer. Alloy formation was confirmed by analyzing the interplanar spacings measured by diffraction techniques; the interplanar spacings obtained showed good agreement with those derived from Vegard's law. The nanoparticles had elemental composition ratios close to the molar ratios of ions in the mixed solutions, implying a high reduction yield. High-resolution transmission electron microscopy images of nanoparticles revealed that the particles were crystalline and were not phase segregated. Binary nanoparticles from Au-Pt and Ag-Pt immiscible systems were also synthesized to confirm the applicability of this method to ternary systems. The formation of nanoalloys by intense femtosecond laser irradiation was possible due to the fast reduction of the mixed ions by solvated electrons and hydrogen radicals generated in situ during irradiation.
金-铂-银（Au-Pt-Ag）离子混合物在氨和聚乙烯吡咯烷酮存在下通过飞秒激光辐照水溶液共还原金属离子，生成平均粒径为 5nm 的纳米颗粒合金，聚乙烯吡咯烷酮用作稳定剂。通过分析衍射技术测量的面间距证实了合金的形成；得到的面间距与维加德定律推导的面间距吻合较好。纳米颗粒的元素组成比接近混合溶液中离子的摩尔比，表明还原产率很高。高分辨率透射电子显微镜图像显示，这些颗粒是结晶的，没有相分离。还合成了来自 Au-Pt 和 Ag-Pt 不混溶体系的二元纳米颗粒，以确认该方法对三元体系的适用性。由于混合离子在辐照过程中就地生成的溶剂化电子和氢自由基的快速还原，强飞秒激光辐照可以形成纳米合金。
