Contribution from the State Key Laboratory for Supramolecular Structures and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
Nanoscale. 2012 Aug 21;4(16):5071-6. doi: 10.1039/c2nr30957b. Epub 2012 Jul 9.
A new approach was developed to control the size of gold nanoparticles in citrate reduction by altering the concentration of chloride ions. The size of the as-prepared gold nanoparticles could be tuned in the range 19-47 nm at a specific molar ratio of citrate and tetrachloroauric acid (5:1) by simply changing the concentration of chloride ions from 0 to 20 mM. UV-visible spectra and TEM observations showed that the increased size of the gold particles was primarily related to the promoted aggregation of the primary gold particles. The aggregation was attributed to their decreased surface charge as the chloride ion concentration in the reaction solutions increased. This approach could also be extended to other reaction systems, for example, the size of gold nanoparticles prepared by NaBH(4) reduction increased from 3 to 12 nm as the chloride ion concentration was increased from 0 to 20 mM.
通过改变氯离子的浓度，开发了一种新的方法来控制柠檬酸钠还原法制备的金纳米粒子的尺寸。通过简单地将氯离子的浓度从 0 增加到 20mM，可以将在特定的柠檬酸钠和四氯金酸摩尔比（5:1）下制备的金纳米粒子的尺寸调至 19-47nm 范围内。紫外-可见光谱和 TEM 观察表明，金颗粒尺寸的增加主要与初级金颗粒的促进聚集有关。这种聚集归因于随着反应溶液中氯离子浓度的增加，金纳米粒子表面电荷的减少。这种方法也可以扩展到其他反应体系，例如，通过硼氢化钠还原法制备的金纳米粒子的尺寸从 3nm 增加到 12nm，当氯离子浓度从 0 增加到 20mM 时。
