Shape Control of Silver Nanoparticles by Stepwise Citrate Reduction
Shape Control of Silver Nanoparticles by Stepwise Citrate Reduction
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通过逐步柠檬酸盐还原控制银纳米颗粒的形状
DOI：
10.1021/jp900775b
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发表时间：
2009-04-23
影响因子：
3.7
通讯作者：
Yang, Wensheng
中科院分区：
文献类型：
--
作者：
Dong, Xinyi;Ji, Xiaohui;Yang, Wensheng
系统且定量地研究了在pH值为5.7至11.1范围内通过柠檬酸还原硝酸银来制备银纳米粒子的过程。随着pH值的升高，银前驱体（Ag⁺）的还原得到促进，这归因于在高pH值下柠檬酸还原剂具有更高的活性。在高pH值下，由于前驱体的快速还原速率，产物由球形和棒状银纳米粒子组成。在低pH值下，由于前驱体的缓慢还原速率，产物主要由三角形或多边形银纳米粒子主导。在所研究的pH范围内，通过一步柠檬酸还原法无法获得以球形银纳米粒子为主的产物，这表明反应中的成核和生长过程之间平衡不佳。基于定量分析的结果，提出了一种分步还原法，即分别在高pH值和低pH值下进行成核和生长过程，用于合成球形银纳米粒子。
Growth of silver nanoparticles by the citrate reduction of silver nitrate under the range of pH from 5.7 to 11.1 was investigated systematically and quantitatively. Reduction of the silver precursor (Ag+) was promoted with increased pH, attributed to the higher activity of the citrate reductant under high pH value. Under high pH, the product was composed of both spherical and rod-like silver nanoparticles as a result of the fast reduction rate of the precursor. Under low pH, the product was mainly dominated by triangle or polygon silver nanoparticles due to the slow reduction rate of the precursor. The product that is dominated by spherical silver nanoparticles cannot be acquired by the one-step citrate reduction method in the range of pH investigated, indicating the poor balance between the nucleation and growth processes in the reactions. On the basis of the results of quantitative analyses, a stepwise reduction method, in which the nucleation and growth processes were carried out ay high and low pH, respectively, was proposed for the syntheses of spherical silver nanoparticles.