Vasquez Yolanda, Sra Amandeep K, Schaak Raymond E
Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, USA.
J Am Chem Soc. 2005 Sep 14;127(36):12504-5. doi: 10.1021/ja054442s.
Hollow metal nanospheres are of interest for a variety of academic and technological applications, including drug delivery, catalysis, plasmonics, and lightweight structural composites. Despite recent advances in synthesizing metal nanostructures with controlled morphologies, there are very few reports of hollow bimetallic nanospheres, although such systems promise to offer advantages over single-metal systems. Here, were report a one-pot synthetic strategy for accessing hollow CoPt nanospheres with a Co-Pt alloy structure. The approach utilizes an in situ Co template and exploits galvanic displacement reactions to selectively dissolve the Co core while depositing a Pt shell. The combination of reducing conditions and a polymer stabilizer appears to allow the Co and Pt to co-reduce and form a Co-Pt fcc alloy phase with a morphology that is templated by the sacrificial Co core. The hollow CoPt nanospheres, which show magnetic hysteresis at low temperatures, are thermally stable up to 300 degrees C. The approach, which adds to a growing toolbox of reactions that yield morphologically controlled magnetic CoPt and FePt nanomaterials, is likely to be general for a variety of alloy systems.
空心金属纳米球在包括药物递送、催化、等离子体学和轻质结构复合材料等多种学术和技术应用中备受关注。尽管最近在合成具有可控形态的金属纳米结构方面取得了进展，但关于空心双金属纳米球的报道却非常少，尽管这类体系有望比单金属体系具有更多优势。在此，我们报道了一种一锅法合成策略，用于制备具有Co-Pt合金结构的空心CoPt纳米球。该方法利用原位Co模板，并通过电置换反应选择性地溶解Co核，同时沉积Pt壳。还原条件和聚合物稳定剂的组合似乎使得Co和Pt能够共还原，并形成具有由牺牲性Co核模板化形态的Co-Pt面心立方合金相。空心CoPt纳米球在低温下表现出磁滞现象，在高达300摄氏度时热稳定。该方法为生成形态可控的磁性CoPt和FePt纳米材料的反应工具箱增添了内容，可能适用于多种合金体系。
