School of Materials Science and Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia.
Langmuir. 2010 Mar 16;26(6):4400-8. doi: 10.1021/la903470f.
This study discusses the function of citrate ions in the synthesis of silver nanoplates through a synergetic reduction approach in ambient conditions. It was found that the citrate ions can play multiple roles in the synthesis process, including a reducing agent, a stabilizer, and a complex agent, and they show some unique features under the reported conditions. The reducing ability of these citrate ions was shown to be weaker than that of sodium borohydride and/or L-ascorbic acid used in the same system. The stability in the shape/size control of silver particles is weaker than that of other surfactants tested in the present system, such as bis(2-ethylhexyl)sulfosuccinate (AOT) and thiols. Citrate ions could form a silver complex with silver ions as [Ag(2)(+)...citrate] or Ag(3)(C(6)H(5)O(7))(n+1), as confirmed by electrospray ionization (ESI) mass spectrometry and the kinetic analysis that the molar ratio of citric acid or sodium citrate to silver ions can greatly influence the reaction rate and, hence, the particle growth of silver nanoparticles. Such a complexing effect is further confirmed by the use of chelating ions (e.g., Fe(CN)(6)) to form Ag(n)Fe(CN)(6), which can largely influence the synthesis of silver nanoparticles. These results show some formation results of generating silver nanoplates involving citrate ions, which are useful in the shape-controlled synthesis of other metallic nanoparticles with desirable functionalities.
本研究通过在环境条件下的协同还原方法讨论了柠檬酸根离子在银纳米片合成中的作用。研究发现，柠檬酸根离子在合成过程中可以发挥多种作用，包括还原剂、稳定剂和络合剂，并且在报道的条件下表现出一些独特的性质。这些柠檬酸根离子的还原能力比同一体系中使用的硼氢化钠和/或 L-抗坏血酸弱。在银颗粒的形状/尺寸控制方面的稳定性比本体系中测试的其他表面活性剂（如双（2-乙基己基）磺基琥珀酸钠（AOT）和硫醇）弱。柠檬酸根离子可以与银离子形成银配合物，如 [Ag(2)(+)...citrate] 或 Ag(3)(C(6)H(5)O(7))(n+1)，这一点通过电喷雾电离（ESI）质谱和动力学分析得到了证实，其中柠檬酸或柠檬酸钠与银离子的摩尔比可以极大地影响反应速率，从而影响银纳米颗粒的颗粒生长。这种络合作用进一步通过使用螯合离子（如 Fe(CN)(6)）形成 Ag(n)Fe(CN)(6) 得到证实，这可以极大地影响银纳米颗粒的合成。这些结果表明了一些涉及柠檬酸根离子的生成银纳米片的形成结果，这对于具有所需功能的其他金属纳米颗粒的形状控制合成是有用的。
