Size control and shape evolution of single-twinned platinum nanocrystals in a room temperature colloidal synthesis
Size control and shape evolution of single-twinned platinum nanocrystals in a room temperature colloidal synthesis
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DOI：
10.1039/c4ce01342e
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发表时间：
2014-10
期刊：
影响因子：
3.1
通讯作者：
Milena Osmić;J. Kolny-Olesiak;K. Al‐Shamery
中科院分区：
文献类型：
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作者：
Milena Osmić;J. Kolny-Olesiak;K. Al‐Shamery
尺寸在几纳米范围内的铂纳米晶体是催化应用的特别有趣的候选者。我们提出了一种简单的低温程序，可以精确地控制这种材料的尺寸。在甲苯溶液中，用硼氢化四丁基铵在室温下还原氯化铂，得到均匀的铂纳米颗粒。十二胺作为配体。通过将铂单体和还原剂缓慢加入到预制的2nm种子中，可以将所得颗粒的大小控制在2 ~ 5nm之间。此外，还可以合成四足体形状的粒子。与通常导致细长结构形成的动力学控制相反，对四足动物生长过程的分析表明，这是一个反应控制的生长过程。通过粉末x射线衍射和高分辨率电子显微镜对其结构进行了研究，发现四足动物的两个分支沿< 111 >方向生长，而另外两个分支沿< 220 >方向生长。这种不寻常的四足动物形状归因于平行于< 220 b>方向的双缺陷的存在。因此，本文中提出的方法允许形成具有高产量的单双缺陷的铂颗粒。
Platinum nanocrystals in the size range of a few nanometers are especially interesting candidates for catalytic applications. We present an easy, low-temperature procedure, which allows for a precise size control of this material. Uniform platinum nanoparticles were obtained by reduction of platinum(IV)chloride with tetrabutylammonium borohydride in toluene solution at room temperature. Dodecylamine served as a ligand. The size of the resulting particles could be controlled in the range between 2 and 5 nm by slow addition of platinum monomers and the reducing agent to preformed 2 nm seeds. Furthermore, particles with a tetrapod shape could be synthesized. In contrast to the usual kinetic control leading to the formation of elongated structures, the analysis of the growth process of the tetrapods suggests a reaction-controlled growth process. Their structure was investigated by powder X-ray diffraction and high-resolution electron microscopy, which revealed that two branches of the tetrapods grow along the 〈111〉 direction, while the other two show growth in the 〈220〉 direction. This uncommon shape of the tetrapods is attributable to the presence of a twin defect parallel to the 〈220〉 direction. Thus, the method presented in the article allows for the formation of platinum particles with a single twin defect with a high yield.