Synthesis of Bimetallic Au@Pt Nanoparticles with Au Core and Nanostructured Pt Shell toward Highly Active Electrocatalysts
Synthesis of Bimetallic Au@Pt Nanoparticles with Au Core and Nanostructured Pt Shell toward Highly Active Electrocatalysts
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DOI：
10.1021/cm102074w
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发表时间：
2010-12-14
影响因子：
8.6
通讯作者：
Yamauchi, Yusuke
中科院分区：
文献类型：
--
作者：
Ataee-Esfahani, Hamed;Wang, Liang;Yamauchi, Yusuke
在低浓度表面活性剂存在下，通过化学还原H2 PtCl 6和FlAuCl（4）物种，成功地合成了具有纳米结构树枝状Pt壳的Au@Pt纳米胶体。通过施加超声处理，Au@Pt纳米胶体的粒径显著减小，并且它们的粒径分布变得非常窄。两种可溶性金属盐（Au（III）和Pt（IV）物种）的还原电位的差异在核-壳结构的一步合成中起关键作用。由于不同的还原电位，Au离子的还原优先在短时间内发生以形成Au晶种。紫外-可见光吸收光谱和透射电子显微镜证实了Pt纳米树枝状纳米线在Au种子上的过度生长。有趣的是，通过控制起始前体溶液中的Pt/Au摩尔比，可以容易地调节Au核上的Pt壳厚度。通过对Pt壳层厚度的优化，可以提高Au@Pt纳米胶体作为甲醇氧化反应的电催化剂的活性，这对提高Pt催化剂的利用效率具有重要意义。
Au@Pt nanocolloids with nanostructured dendritic Pt shells are successfully synthesized by chemically reducing both H2PtCl6 and FlAuCl(4) species in the presence of a low-concentration surfactant solution. By applying an ultrasonic treatment, the particle size of the Au@Pt nanocolloids is dramatically decreased and their size distribution becomes very narrow. The difference in reduction potentials of the two soluble metal salts (Au(III) and Pt(IV) species) plays a key role in the one-step synthesis of the core-shell structure. Because of the different reduction potentials, the reduction of Au ions preferentially occurs over a short time to form the Au seeds. It is followed by overgrowth of Pt nanodendritic nanowires on the Au seeds, which is confirmed by ultraviolet-visible light absorption spectroscopy and transmission electron microscopy. Interestingly, the Pt shell thicknesses on Au cores can be easily tuned by controlling the Pt/Au molar ratios in the starting precursor solutions. Through the optimization of the Pt shell thicknesses, the Au@Pt nanocolloids can exhibit enhanced activity as an electrocatalyst for a methanol oxidation reaction, which will be important to improve the utilization efficiency of Pt catalysts in the future.