Green Mobility Collaborative Research Center, Nagoya University, Nagoya 464-8603, Japan.
Nanotechnology. 2013 Feb 8;24(5):055604. doi: 10.1088/0957-4484/24/5/055604. Epub 2013 Jan 16.
In this study, we investigate a new synthetic route, termed the solution plasma process, for the synthesis of colloidal copper nanoparticles (CuNPs) in the presence of an amide and acid capping agent. Gelatin and ascorbic acid were selected as the capping agents to protect the particles against coalescence and oxidation side reaction. Using a high voltage power supply, CuNPs were rapidly formed by 1 min after the discharge. The size and shape of the CuNPs were dependent on the discharge time and were clearly influenced by the effect of the capping agents under two characteristics of the discharge medium (pH and temperature). With a long discharge time, the CuNP size tended to decrease with the formation of anisotropic particle morphologies: spherical, cubic, hexagonal, triangular and rod-like shapes. The decrease in CuNP size as a function of discharge time could be explained by the dissolution of CuNPs in a lower pH solution. After 5 min discharge the capping agent evidently allowed the protection of the synthesized CuNPs against oxidation with the presence of anisotropic CuNP shapes. It is demonstrated that the CuNP shape could be tuned from spherical to anisotropic shapes without the undesirable oxidation by adjusting the discharge time of the solution plasma. These advantages are valuable for material engineering to design the properties of Cu-based nanoparticles for the desired applications.
在这项研究中，我们研究了一种新的合成途径，称为溶液等离子体过程，用于在酰胺和酸封端剂存在下合成胶体铜纳米粒子 (CuNPs)。明胶和抗坏血酸被选为封端剂，以防止颗粒团聚和氧化副反应。使用高压电源，在放电 1 分钟后迅速形成 CuNPs。CuNPs 的尺寸和形状取决于放电时间，并受放电介质（pH 值和温度）两个特性下封端剂的影响。随着放电时间的延长，CuNP 的尺寸趋于减小，同时形成各向异性的颗粒形态：球形、立方、六方、三角形和棒状。CuNP 尺寸随放电时间的减小可以用 CuNPs 在较低 pH 值溶液中的溶解来解释。在 5 分钟的放电后，封端剂显然允许合成的 CuNPs 在存在各向异性 CuNP 形状的情况下免受氧化。结果表明，通过调整溶液等离子体的放电时间，可以将 CuNP 的形状从球形调谐为各向异性形状，而不会发生不必要的氧化。这些优势对于材料工程设计具有理想应用的基于 Cu 的纳米粒子的特性是有价值的。
