State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China.
Nanoscale. 2014 Mar 21;6(6):3309-15. doi: 10.1039/c3nr06186h. Epub 2014 Feb 11.
Here, we demonstrate that graphene oxide (GO) can act as a structure-directing agent for the formation of PtPd alloy concave nanocubes enclosed by high index facets. In the presence of GO, PtPd alloy concave nanocubes could be easily tailored by a simple hydrothermal reaction. In sharp contrast, only cubic PtPd alloy nanocrystals were obtained in the absence of GO. Moreover, compared to the unsupported PtPd nanocubes, the composition ratio of Pt to Pd changed significantly from 1 : 1 to 3 : 1. Due to the exposed high-index facets and the strong interaction between catalysts and graphene support, the as-synthesized PtPd concave nanocubes exhibited enhanced electrocatalytic activity and high durability toward methanol oxidation. The present work highlights the unique role of GO in the formation of metal nanocrystals as not only a catalyst support but also a structure- and/or morphology-directing agent, due to the presence of various functional groups on GO sheets. The present GO-assisted approach provides a new avenue to the synthesis of nanocrystals with high-index facets and initiates new opportunities for the exploration of high-performance graphene-based nanocatalysts.
在这里，我们证明氧化石墨烯（GO）可以作为形成由高指数晶面封闭的 PtPd 合金凹纳米立方体形貌的结构导向剂。在 GO 的存在下，通过简单的水热反应可以很容易地制备 PtPd 合金凹纳米立方体形貌。相比之下，在没有 GO 的情况下，只能得到立方 PtPd 合金纳米晶。此外，与无载体 PtPd 纳米立方体形貌相比，Pt 与 Pd 的组成比从 1:1 显著变化到 3:1。由于暴露的高指数晶面和催化剂与石墨烯载体之间的强相互作用，所合成的 PtPd 凹纳米立方体形貌表现出增强的电催化活性和对甲醇氧化的高耐久性。本工作突出了 GO 在形成金属纳米晶中的独特作用，不仅作为催化剂载体，而且由于 GO 片上存在各种官能团，还作为结构和/或形貌导向剂。本工作中的 GO 辅助方法为合成具有高指数晶面的纳米晶提供了新途径，并为探索高性能基于石墨烯的纳米催化剂开辟了新的机会。
