Green Mobility Collaborative Research Center, Nagoya University, Nagoya 464-8603, Japan.
Nanotechnology. 2012 Oct 5;23(39):395602. doi: 10.1088/0957-4484/23/39/395602. Epub 2012 Sep 11.
Arc discharge in solution, generated by applying a high voltage of unipolar pulsed dc to electrodes of Ag and Pt, was used as a method to form Ag/Pt bimetallic nanocomposites via electrode erosion by the effects of the electric arc at the cathode (Ag rod) and the sputtering at the anode (Pt rod). Ag/Pt bimetallic nanocomposites were formed as colloidal particles dispersed in solution via the reduction of hydrogen radicals generated during discharge without the addition of chemical precursor or reducing agent. At a discharge time of 30 s, the fine bimetallic nanoparticles with a mean particle size of approximately 5 nm were observed by transmission electron microscopy (TEM). With increasing discharge time, the bimetallic nanoparticle size tended to increase by forming an agglomeration. The presence of the relatively small amount of Pt dispersed in the Ag matrix could be observed by the analytical mapping mode of energy-dispersive x-ray spectroscopy and high-resolution TEM. This demonstrated that the synthesized particle was in the form of a nanocomposite. No contamination of other chemical substances was detected by x-ray photoelectron spectroscopy. Hence, solution plasma could be a clean and simple process to effectively synthesize Ag/Pt bimetallic nanocomposites and it is expected to be widely applicable in the preparation of several types of nanoparticle.
采用在 Ag 和 Pt 电极上施加单向脉冲直流高电压的方法，在溶液中产生电弧放电，通过阴极（Ag 棒）处电弧和阳极（Pt 棒）处溅射的影响来实现电极侵蚀，从而形成 Ag/Pt 双金属纳米复合材料。Ag/Pt 双金属纳米复合材料通过放电过程中生成的氢自由基还原形成胶体颗粒分散在溶液中，而无需添加化学前体或还原剂。在放电时间为 30 s 的情况下，通过透射电子显微镜（TEM）观察到具有约 5nm 平均粒径的细小双金属纳米颗粒。随着放电时间的增加，通过形成团聚体，双金属纳米颗粒的尺寸趋于增大。通过能量色散 X 射线能谱的分析映射模式和高分辨率 TEM 可以观察到相对少量的 Pt 分散在 Ag 基体中。这表明合成的颗粒为纳米复合材料的形式。X 射线光电子能谱未检测到其他化学物质的污染。因此，溶液等离子体可能是一种清洁且简单的工艺，可有效合成 Ag/Pt 双金属纳米复合材料，预计在制备几种类型的纳米颗粒方面具有广泛的应用前景。
