Synthesis of Nanohole‐Structured Single‐Crystalline Platinum Nanosheets Using Surfactant‐Liquid‐Crystals and their Electrochemical Characterization
Synthesis of Nanohole‐Structured Single‐Crystalline Platinum Nanosheets Using Surfactant‐Liquid‐Crystals and their Electrochemical Characterization
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DOI：
10.1002/adfm.200800966
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发表时间：
2009-02
影响因子：
19
通讯作者：
T. Kijima;Yuya Nagatomo;H. Takemoto;M. Uota;Daisuke Fujikawa;Yuzo Sekiya;T. Kishishita;M. Shimoda;T. Yoshimura;H. Kawasaki;G. Sakai
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文献类型：
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作者：
T. Kijima;Yuya Nagatomo;H. Takemoto;M. Uota;Daisuke Fujikawa;Yuzo Sekiya;T. Kishishita;M. Shimoda;T. Yoshimura;H. Kawasaki;G. Sakai
纳米孔结构的单晶铂纳米片是由Na2PtCl6的硼氢化物还原合成的，它被限制在有或没有非乙二醇（C12EO9）的聚氧乙烯（20）山梨醇单油酸酯（Tween 80）的溶致液晶（LLCs）中。中心厚度约为4-10 nm，直径达500 nm或以上的铂纳米片具有许多宽约1.8 nm的六角形纳米孔。纳米片的高分辨率电子显微镜图像显示，原子条纹的间距为0.22 nm，表明纳米片在纳米空穴和非空穴区域的晶体结构是连续的。六角形纳米孔的内角分布表明，纳米孔的六个侧面分别有两个Pt（111）、Pt （1${\bar{1}}$1）和Pt（010）平面。基于所得到的固体及其前驱体的结构和成分数据，并借助于在不含吐温80但含有油酸的体系中观察到的类似纳米孔生长情况，讨论了纳米孔Pt纳米片的形成机制。研究还表明，负载在碳上的纳米孔Pt纳米结构在氧还原反应中表现出相当高的电催化活性，并且作为聚合物电解质燃料电池的阴极材料具有很高的性能，同时通过电子辐照效应显示出极高的热稳定性。
Nanohole‐structured single‐crystalline Pt nanosheets have been synthesized by the borohydride reduction of Na2PtCl6 confined to the lyotropic liquid crystals (LLCs) of polyoxyethylene (20) sorbitan monooleate (Tween 80) with or without nonaethylene‐glycol (C12EO9). The Pt nanosheets of around 4–10 nm in central thickness and up to 500 nm or above in diameter have a number of hexagonal‐shaped nanoholes ∼1.8 nm wide. High‐resolution electron microscope images of the nanosheets showed atomic fringes with a spacing of 0.22 nm indicating that the nanosheets are crystallographically continuous through the nanoholed and non‐holed areas. The inner‐angle distributions for the hexagonal nanoholes indicate that the six sides of the nanoholes are walled with each two Pt (111), Pt (1${\bar {1}}$1) and Pt (010) planes. The formation mechanism of nanoholed Pt nanosheets is discussed on the basis of structural and compositional data for the resulting solids and their precursory LLCs, with the aid of similar nanohole growth observed for a Tween 80 free but oleic acid‐incorporated system. It is also demonstrated that the nanoholed Pt nanostructures loaded on carbon exhibit fairly high electrocatalytic activity for oxygen reduction reaction and a high performance as a cathode material for polymer‐electrolyte fuel cells, along with their extremely high thermostability revealed through the effect of electron‐irradiation.