One-pot room-temperature synthesis of single-crystalline gold nanocorolla in water.
One-pot room-temperature synthesis of single-crystalline gold nanocorolla in water.
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DOI：
10.1021/ja904910m
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发表时间：
2009-09
影响因子：
15
通讯作者：
Tetsuro Soejima;N. Kimizuka
中科院分区：
文献类型：
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作者：
Tetsuro Soejima;N. Kimizuka
开发了一种室温纳米雕刻策略来制造具有花冠和螺旋桨状结构的复杂金纳米片。它是基于在水溶液中同时生长和蚀刻金纳米片，这发生在Au（OH）（4）（-）离子的光还原过程中。溴离子、聚乙烯吡咯烷酮（PVP）和分子氧的存在是必不可少的，其中溴离子起着多种作用。首先，它们通过在fcc（111）表面上形成吸附层来促进纳米片结构的形成。第二，它们通过将氧化的Au（I）物质转化为可溶性AuBr（2）（-）离子，从而促进金纳米晶体的氧化溶解，这导致金纳米晶体的形成。PVP还稳定金纳米片的成核。虽然整个反应在一锅中进行，但晶体生长和蚀刻显示出相互作用，并且由于Au（OH）（4）（-）和其他物质的浓度随时间的变化而以不同的动力学发生。在这些条件下形成的花冠状或螺旋桨状的金纳米片是单晶的，如通过选区电子衍射图案和莫尔条纹的观察所示。花冠状或螺旋桨状的金纳米片的形态是可控的，这取决于溴离子和PVP在水溶液混合物中的浓度。在此基础上，提出了一个初步的机制，其中涉及的同时晶体生长和表面的氧化蚀刻的纳米晶体。
A room-temperature nanocarving strategy is developed for the fabrication of complex gold nanoplates having corolla- and propeller-like architectures. It is based on the simultaneous growth and etching of gold nanoplates in aqueous solution, which occur in the course of photoreduction of Au(OH)(4)(-) ions. The presence of bromide ion, poly(vinylpyrrolidone) (PVP), and molecular oxygen is indispensable, where bromide ions play multiple roles. First, they promote formation of nanoplate structures by forming adlayers on the fcc(111) surface. Second, they facilitate oxidative dissolution of gold nanocrystals by converting the oxidized Au(I) species to soluble AuBr(2)(-) ions, which lead to the formation of ultrathin nanocrevasses. PVP also stabilizes the nucleation of gold nanoplates. Although the overall reactions proceed in one-pot, the crystal growth and etching show interplay and occur with different kinetics due to changes in the concentration of Au(OH)(4)(-) and other species with time. Corolla- or propeller-like gold nanoplates formed under these conditions are single-crystalline, as indicated by selected area electron diffraction patterns and the observation of moire fringes. The morphology of corolla- or propeller-like gold nanoplates is controllable depending on the concentration of bromide ion and PVP in the aqueous mixture. On the basis of these results, a preliminary mechanism is proposed which involves the concurrent crystal growth and oxidative etching on the surface of nanocrystals.