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通过溶剂热法,成功制备了准凹面体状Pt-Ni合金纳米结构.不同角度的透射电镜照片和三维模型图表明,准凹面体与以立方八面体为基底,在其十二个顶点进行外延生长所形成的结构相对应.高分辨电镜(HRTEM),选区电子衍射(SAED)和X射线粉末衍射(XRD)表征结果表明,外延部分与内核部分组成成分不同.在进行系统对照实验的基础上提出了同步刻蚀-过生长机理来解释准凹面体的形成过程.电化学测试表明,准凹面体对甲醇氧化具有很高的催化活性,按质量归一的催化活性是相同条件下制备所得纯Pt颗粒的3倍,是商用Pt/C的13.6倍.X射线光电子能谱数据表明,Ni的引入有效降低了Pt的原子结合能,这可能对催化活性的提高起到了关键作用.
The nanocomposites of Pt-Ni alloy with quasi-concave surface were prepared successfully by solvothermal method. TEM images and three-dimensional model images show that the quasi-concave and the cubic octahedron are the base and epitaxy at the twelve vertices (HRTEM), selected area electron diffraction (SAED) and X-ray powder diffraction (XRD) results show that the composition of the outer part and the inner part of the core are different.On the basis of the systematic control experiment The mechanism of simultaneous etching and overgrowth is proposed to explain the formation of quasi-concave body.Electrochemical tests show that the quasi-concave body has high catalytic activity for methanol oxidation and the mass-normalized catalytic activity is obtained under the same conditions 3 times that of Pt particles, which is 13.6 times of commercial Pt / C. The X-ray photoelectron spectroscopy data show that the introduction of Ni effectively reduces the atomic binding energy of Pt, which may play a key role in improving the catalytic activity.