原子级壳层厚度Ru@Pt核壳结构纳米粒子的制备与表征

采用连续多元醇法,以RuCl₃·xH₂O和PtCl₂为前驱体,乙二醇为还原剂,聚乙烯吡咯烷酮为稳定剂的反应体系,并通过调节PtCl₂用量和还原温度成功制备了壳层厚度约为1.5个Pt原子层的单分散Ru@Pt核壳结构纳米粒子,利用透射电子显微镜(TEM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)等分析方法对其微观结构、粒径分布、晶型结构、物相组成进行了表征。 结果表明,该纳米粒子分布均匀且基本为球形,平均粒径约为3.57 nm,其中内核直径约为2.49 nm,外壳厚度约为0.55 nm,壳层金属Pt具有很好的晶型,Pt原子主要为{111}晶面,内核金属Ru与外壳金属Pt互相产生了电子效应使Pt的衍射峰和Ru、Pt的电子结合能产生了一定偏移,并初步研究了有效控制该核壳结构纳米粒子壳层厚度和增强核与壳两种金属之间电子效应的因素,使其有望在催化等领域发挥潜在的应用价值。

Preparation and Characterization of Ru@Pt Core-Shell Nanoparticles with Shell in Atomic Thickness

Through regulating the amount of PtCl₂ and the temperature of reduction, Ru@Pt core-shell monodisperse nanoparticles comprising a Ru core covered with an approximately 1.5 monolayer-thick shell of Pt atoms were synthesized by using a sequential polyol process with RuCl₃·xH₂O and PtCl₂ as precursors, ethylene glycol as the reductant and polyvinylpyrrolidone as the stabilizer. The microstructure, size-distribution, crystal structure and phase composition of nanoparticles were characterized by transmission electron microscopy(TEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and other analytical methods. The results indicate that the nanoparticles are uniformly distributed and spherical with 3.57 nm average size. The core is about 2.49 nm and the shell is about 0.55 nm. Pt shell has a nice crystalline phase which is mainly {111} lattice fringes. The production of electronic effect is found between Ru core and Pt shell, and this makes the diffraction peak of Pt and the electron binding energy of Ru and Pt produce a certain offset. The factors controlling the thickness of the shell of nanoparticles and strengthening the electronic effect between Ru core and Pt shell have been investigated preliminarily. The Ru@Pt core-shell nanoparticles are expected to have great potential in catalysis and other fields.