Kinetics of Halide-Induced Decomposition and Aggregation of Silver Nanoparticles
Kinetics of Halide-Induced Decomposition and Aggregation of Silver Nanoparticles
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DOI：
10.1021/jp3011926
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发表时间：
2012-04-12
影响因子：
3.7
通讯作者：
Peterson, Karen I.
中科院分区：
文献类型：
--
作者：
Espinoza, M. Gabriela;Hinks, Mallory L.;Peterson, Karen I.
我们对氟化钠、氯化钠、溴化钠和碘化钠对5纳米银纳米粒子水溶液的影响进行了动力学研究。这些卤化物之间存在明显差异，我们将其归因于两种相互竞争的、由卤化物引发的过程：纳米粒子表面的氧化分解和纳米粒子的聚集。氟化钠基本上不与纳米粒子表面发生反应，但在浓度高于约75毫摩尔时会引发聚集，尽管这种聚集是不稳定的。氯化钠在浓度低于27毫摩尔时发生氧化反应，但由于表面钝化，反应非常缓慢。在27毫摩尔时出现明显且较低的聚集起始点，这是因为氯离子形成了一层均匀的层，将纳米粒子表面的电荷降低到其原始值的约2/3。添加碘化钠或溴化钠的情况则大不相同；氧化分解的速率比氯化钠快几个数量级，以至于聚集的起始点不太明显。
We present a kinetic study of the effects of NaF, NaCl, NaBr, and NaI on aqueous solutions of S nm silver nanoparticles. There are distinct differences between these halides, which we attribute to two competing, halide-induced processes: oxidative decomposition of the nanoparticle surfaces and aggregation of the nanoparticles. NaF essentially does not react with the nanoparticle surface, but at concentrations above about 75 mM induces aggregation, albeit erratically. NaCl reacts oxidatively at concentrations below 27 mM, but the reaction is very slow because of surface passivation. The distinct, and lower, onset of aggregation at 27 mM is explained by chloride ion forming a uniform layer, which lowers the charge on the nanoparticle surface to about 2/3 of its original value. Addition of NaI or NaBr is very different; the rate of oxidative decomposition is orders of magnitude faster than that of NaCl such that the onset of aggregation is less apparent.