摘要
奈米粒子的形狀控制在現今材料研究是相當重要的方向，在於奈米尺度下的形狀變化對於材料的光學、磁學、催化性質有明顯的影響。因此我們發展多元醇還原合成系統(polyol reduction)來控制PtRu合金奈米粒子的形狀。藉由Pt(acac)2及Ru(acac)3於高溫下與介面活性劑；oleic acid、oleylamine交互作用及反應，並利用改變還原劑濃度、反應溫度、反應時間等方式產生不同生長機制，進而得到PtRu dentrimer、multipod、cuboctahedron。最後探討在本系統中因各個實驗參數對於成核及成長速率的影響，進而造成奈米粒子上形貌的變化。
在催化反應中，催化劑的形狀結構對於反應活性的影響在近期文獻中已有許多研究發表。因此本實驗將PtRu dentrimer、multipod、cuboctahedron與Pt-JM、PtRu-JM在硫酸溶液系統進行氧氣還原及甲醇氧化反應測試，於氧氣還原反應中，dentrimer、multipod與cuboctahedron的specific activity皆比商用Pt-JM來的好，而對於甲醇氧化反應，dentrimer擁有比PtRu-JM更佳的onset potential。由以上實驗的結果瞭解形狀對於各種催化反應會有不同的催化效果。

In the recent study of nanomaterial, the shape control of nanoparticles has been a major subject because of the obvious effects in optics, magnetism and catalysis. In this work, we developed the polyol reduction for the shape control of PtRu nanoalloys. Pt(acac)2 and Ru(acac)3 were used as metallic precursors and reacted with surfactants including oleic acid and oleyl amine at high temperature. When the experimental parameters such as the concentration of reducing agent, reaction temperature and reaction time were adjusted, the PtRu nanoalloy with different shape including dentrimer, multipod and cuboctahedron were prepared. The mechanisms of PtRu nanoalloy with different shapes were discussed. Consequently, we considered that the interreaction between precursors and surfactants influenced on the nucleation and growth rate during the formation of PtRu nanoalloy.
To date, the effects of structure of PtRu nanoalloy in the catalytic reaction have been studied extensively. We used PtRu nanoalloy with different shapes (dentrimer, multipod and cuboctahedron) as catalyst and measured their catalytic activity in oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR). The measurements in ORR showed that the specific activity of dentrimer, multipod and cuboctahedron are higher than that of Pt-JM. Moreover, the results in MOR showed the onset potential of dentrimer is more negative than that of PtRu-JM. In summary, the catalytic activity-shape correlation was demonstrated clearly in our work.

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