Department of Chemistry, Centre for Optical Materials Research (COMSET), and Environmental Toxicology Program, Hunter Laboratories, Clemson University, Clemson, SC 29634, USA.
J Colloid Interface Sci. 2010 Dec 15;352(2):285-91. doi: 10.1016/j.jcis.2010.08.072.
We report a novel and simple hydrothermal method to synthesize silver nanowires using only silver nitrate and sodium citrate without any external seeds or templates. The effects of the molar ratio of silver ions to citrate, pH, and the reaction temperature were investigated. Silver nanowires and particles were characterized using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), and UV/vis absorption spectroscopy. A high yield of nanowires (average diameter 53 ± 4 nm, length up to 6 μm) was obtained under optimized conditions with 1:1 M ratio of Ag(+) to citrate and pH 7.1 (no NaOH added) at 130 °C. Increasing the citrate ratio, increasing the pH with NaOH, or decreasing the reaction temperature all resulted in samples with shorter lengths and fewer nanowires compared to nanospheres. At pH 10.1, monodispersed nanospheres with diameter of 58 ± 9 nm were produced. The nanowire and nanosphere synthetic methods are attractive because of their simplicity, the lack of capping agents besides citrate, and the uniformity of the particles produced.
我们报告了一种新颖而简单的水热法，仅使用硝酸银和柠檬酸钠合成银纳米线，无需任何外部种子或模板。研究了银离子与柠檬酸盐的摩尔比、pH 值和反应温度的影响。使用扫描电子显微镜 (SEM)、高分辨率透射电子显微镜 (HRTEM)、粉末 X 射线衍射 (XRD) 和紫外/可见吸收光谱对银纳米线和颗粒进行了表征。在优化条件下，Ag(+)与柠檬酸盐的摩尔比为 1:1，pH 值为 7.1（未添加 NaOH），在 130°C 下可获得高产率的纳米线（平均直径为 53 ± 4nm，长度可达 6μm）。与纳米球相比，增加柠檬酸盐的比例、用 NaOH 增加 pH 值或降低反应温度都会导致样品的长度变短，纳米线数量减少。在 pH 值为 10.1 时，生成了直径为 58 ± 9nm 的单分散纳米球。该纳米线和纳米球的合成方法具有吸引力，因为它们简单，除了柠檬酸盐之外无需使用封端剂，并且所生成的颗粒均匀。
