Nakamura Takahiro, Sato Shunichi
J Nanosci Nanotechnol. 2015 Jan;15(1):426-32. doi: 10.1166/jnn.2015.8846.
Solid-solution palladium-platinum (Pd-Pt) alloy nanoparticles (NPs) with fully tunable compositions were directly fabricated through high-intensity laser irradiation of an aqueous solution of palladium and platinum ions without using any reducing agents or thermal processes. Transmission electron microscopy (TEM) observations showed that nanometer-sized particles were fabricated by laser irradiation of mixed aqueous solutions of palladium and platinum ions with different feeding ratios. The crystalline nature of the NPs was precisely characterized by X-ray diffraction (XRD). Despite the fact that, for the bulk systems, a pair of XRD peak was detected between the palladium and platinum peaks because of the large miscibility gap in the Pd-Pt binary phase diagram, only a single XRD peak was seen for the Pd-Pt NPs fabricated in the present study. Moreover, the peak position shifted from that of pure palladium towards platinum with increasing fraction of platinum ions in solution. Consequently, the interplanar spacings of the alloy NPs agreed well with the estimated values obtained from Vegard's law. These observations strongly indicate the formation of solid-solution Pd-Pt alloy NPs with fully tunable compositions. This technique is not only a "green" (environmentally-friendly) and facile process, but is also widely applicable to other binary and ternary systems.
通过对钯离子和铂离子的水溶液进行高强度激光照射，无需使用任何还原剂或热过程，直接制备出了成分可完全调控的固溶体钯 - 铂（Pd - Pt）合金纳米颗粒（NPs）。透射电子显微镜（TEM）观察表明，通过激光照射不同进料比的钯离子和铂离子混合水溶液制备出了纳米尺寸的颗粒。利用X射线衍射（XRD）对纳米颗粒的晶体性质进行了精确表征。尽管对于块状体系，由于Pd - Pt二元相图中存在较大的混溶间隙，在钯峰和铂峰之间检测到一对XRD峰，但在本研究中制备的Pd - Pt纳米颗粒仅观察到一个单一的XRD峰。此外，随着溶液中铂离子比例的增加，峰位置从纯钯的峰位置向铂的峰位置移动。因此，合金纳米颗粒的晶面间距与根据维加德定律获得的估计值吻合良好。这些观察结果有力地表明形成了成分可完全调控的固溶体Pd - Pt合金纳米颗粒。该技术不仅是一种“绿色”（环境友好）且简便的过程，而且还广泛适用于其他二元和三元体系。
