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Synthesis of Highly Uniform Nickel Multipods with Tunable Aspect Ratio by Microwave Power Control
ACS Nano ( IF 15.8 ) Pub Date : 2018-06-18 00:00:00 , DOI: 10.1021/acsnano.8b01992 Parth N. Vakil 1 , David A. Hardy 1 , Geoffrey F. Strouse 1
ACS Nano ( IF 15.8 ) Pub Date : 2018-06-18 00:00:00 , DOI: 10.1021/acsnano.8b01992 Parth N. Vakil 1 , David A. Hardy 1 , Geoffrey F. Strouse 1
Affiliation
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As the importance of anisotropic nanostructures and the role of surfaces continues to rise in applications including catalysis, magneto-optics, and electromagnetic interference shielding, there is a need for efficient and economical synthesis routes for such nanostructures. The article describes the application of cycled microwave power for the rapid synthesis of highly branched pure-phase face-centered cubic crystalline nickel multipod nanostructures with >99% multipod population. By controlling the power delivery to the reaction mixture through cycling, superior control is achieved over the growth kinetics of the metallic nanostructures, allowing formation of multipods consisting of arms with different aspect ratios. The multipod structures are formed under ambient conditions in a simple reaction system composed of nickel acetylacetonate (Ni(acac)2), oleylamine (OAm), and oleic acid (OAc) in a matter of minutes by selective heating at the (111) overgrowth corners on Ni nanoseeds. The selective heating at the corners leads to accelerated autocatalytic growth along the ⟨111⟩ direction through a “lightning rod” effect. The length is proprtional to the length and number of microwave (MW)-on cycles, whereas the core size is controlled by continuous MW power delivery. The roles of heating mode (cycling versus variable power versus convective heating) during synthesis of the materials is explored, allowing a mechanism into how cycled microwave energy may allow fast multipod evolution to be proposed.
中文翻译：
微波功率控制合成具有可调长宽比的高度均匀的镍多脚架
随着各向异性纳米结构的重要性和表面的作用在包括催化，磁光和电磁干扰屏蔽的应用中持续上升，因此需要用于此类纳米结构的有效且经济的合成途径。本文介绍了循环微波功率在快速合成高支化纯相，面心立方立方多晶镍多晶镍纳米结构中的应用。通过循环控制向反应混合物的能量传递，可以对金属纳米结构的生长动力学进行出色的控制，从而形成由具有不同纵横比的臂组成的多脚架。2），油胺（OAm）和油酸（OAc）通过在Ni纳米种子的（111）过度生长角处选择性加热而在数分钟内完成。拐角处的选择性加热通过“避雷针”效应导致沿⟨111⟩方向的加速自催化生长。长度与微波开启周期的长度和数量成正比，而磁芯的大小则由连续兆瓦功率的输送来控制。探索了材料合成过程中加热模式（循环与可变功率与对流加热）的作用，从而提出了一种机制，探讨了循环微波能量如何允许快速多脚架演化。
更新日期：2018-06-18
中文翻译：
微波功率控制合成具有可调长宽比的高度均匀的镍多脚架
随着各向异性纳米结构的重要性和表面的作用在包括催化，磁光和电磁干扰屏蔽的应用中持续上升，因此需要用于此类纳米结构的有效且经济的合成途径。本文介绍了循环微波功率在快速合成高支化纯相，面心立方立方多晶镍多晶镍纳米结构中的应用。通过循环控制向反应混合物的能量传递，可以对金属纳米结构的生长动力学进行出色的控制，从而形成由具有不同纵横比的臂组成的多脚架。2），油胺（OAm）和油酸（OAc）通过在Ni纳米种子的（111）过度生长角处选择性加热而在数分钟内完成。拐角处的选择性加热通过“避雷针”效应导致沿⟨111⟩方向的加速自催化生长。长度与微波开启周期的长度和数量成正比，而磁芯的大小则由连续兆瓦功率的输送来控制。探索了材料合成过程中加热模式（循环与可变功率与对流加热）的作用，从而提出了一种机制，探讨了循环微波能量如何允许快速多脚架演化。
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