Phase-segregated Pt-Ni chain-like nanohybrids with high electrocatalytic activity towards methanol oxidation reaction.
Phase-segregated Pt-Ni chain-like nanohybrids with high electrocatalytic activity towards methanol oxidation reaction.
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DOI：
10.1039/c4nr00139g
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发表时间：
2014-04
期刊：
影响因子：
6.7
通讯作者：
Li-li Wang;Dong-Feng Zhang;Lin Guo
中科院分区：
文献类型：
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作者：
Li-li Wang;Dong-Feng Zhang;Lin Guo
在少量PVP的辅助下，通过改进的多元醇法合成了由相互连接的单金属结构组成的相分离的铂镍链状纳米结构。通过简单地调整前驱体的进料比，可以调节铂和镍的摩尔比。高分辨电子显微镜(HR-TEM)和X射线光电子能谱(XPS)结果表明，原子在颗粒状亚基的界面发生了扩散。X射线光电子能谱中Pt4f7/2峰的负移表明电子从镍原子转移到铂原子，而在855.7 eV附近的强峰则表明镍纳米粒子的表面氧化，循环伏安测试进一步证实了这一点。相分离结构的甲醇氧化反应的电催化活性(MOR)高于纯铂纳米粒子，其活性顺序为Pt1Ni1&Gt；Pt3Ni1∼Pt2Ni3>；我们认为，修饰的电子结构和氢氧化镍的存在都有助于提高催化活性。
The phase-segregated Pt-Ni chain-like nanostructures, composed of monometallic counterparts attached to each other, were synthesized via a modified polyol process with the assistance of a small amount of PVP. The molar ratio between Pt and Ni was tuned by simply adjusting the feed ratio of the precursors. High-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) results reveal that atomic diffusion occurred at the interface of the granular subunits. The negative shift of the Pt4f7/2 peak in the XPS spectra indicates the electron transfer from Ni to Pt atoms, while the strong peaks at around 855.7 eV suggest the surface oxidation of the Ni nanoparticles, which was further confirmed by the cyclic voltammetry (CV) measurement. The electrocatalytic activities of the methanol oxidation reaction (MOR) were found to be higher for the phase-segregated structures relative to those for pure Pt nanoparticles, and the activities followed the sequences of Pt1Ni1 > Pt3Ni1 ∼ Pt2Ni3 > pure Pt. We believe that the modified electronic structures and the existence of nickel hydroxide both contributed to the improved catalytic activities.