State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China.
ACS Nano. 2010 Jan 26;4(1):547-55. doi: 10.1021/nn9014483.
Graphene nanosheet, the hottest material in physics and materials science, has been studied extensively because of its unique electronic, thermal, mechanical, and chemical properties arising from its strictly 2D structure and because of its potential technical applications. Particularly, these remarkable characteristics enable it to be a promising candidate as a new 2D support to load metal nanoparticles (NPs) for application in fuel cells. However, constructing high-quality graphene/bimetallic NP hybrids with high electrochemical surface area (ECSA) remains a great challenge to date. In this paper, we demonstrate for the first time a wet-chemical approach for the synthesis of high-quality three-dimensional (3D) Pt-on-Pd bimetallic nanodendrites supported on graphene nanosheets (TP-BNGN), which represents a new type of graphene/metal heterostructure. The resulting hybrids were characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), Raman spectroscopy, and electrochemical technique. It is found that small single-crystal Pt nanobranches supported on Pd NCs with porous structure and good dispersion were directly grown onto the surface of graphene nanosheets, which exhibits high electrochemical active area. Furthermore, the number of nanobranches for Pt-on-Pd bimetallic nanodendrites on the surface of graphene nanosheets could be easily controlled via simply changing the synthetic parameters, thus resulting in the tunable catalytic properties. Most importantly, the electrochemical data indicate that the as-prepared graphene/bimetallic nanodendrite hybrids exhibited much higher electrocatalytic activity toward methanol oxidation reaction than the platinum black (PB) and commercial E-TEK Pt/C catalysts.
石墨烯纳米片是物理和材料科学领域中最热门的材料，由于其严格的二维结构及其潜在的技术应用所带来的独特的电子、热、机械和化学性质，受到了广泛的研究。特别是，这些显著的特性使它成为一种很有前途的新型二维载体，可以负载金属纳米粒子（NPs），应用于燃料电池。然而，构建具有高电化学表面积（ECSA）的高质量石墨烯/双金属 NP 杂化物仍然是一个巨大的挑战。在本文中，我们首次展示了一种湿化学方法，用于合成高质量的三维（3D）负载在石墨烯纳米片上的 Pt-Pd 双金属纳米树突（TP-BNGN），这代表了一种新型的石墨烯/金属异质结构。所得的杂化物通过原子力显微镜（AFM）、透射电子显微镜（TEM）、高分辨率 TEM（HRTEM）、能量色散 X 射线（EDX）光谱、X 射线光电子能谱（XPS）、热重分析（TGA）、拉曼光谱和电化学技术进行了表征。结果发现，小的单晶 Pt 纳米支叉直接生长在石墨烯纳米片的表面上，负载在具有多孔结构和良好分散性的 Pd NCs 上，表现出高电化学活性面积。此外，通过简单地改变合成参数，可以很容易地控制石墨烯纳米片表面上 Pt-Pd 双金属纳米树突的纳米支叉数量，从而实现可调的催化性能。最重要的是，电化学数据表明，所制备的石墨烯/双金属纳米树突杂化物对甲醇氧化反应的电催化活性远高于铂黑（PB）和商业 E-TEK Pt/C 催化剂。
