Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China.
Research Resources Center, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
Nat Commun. 2014;5:3264. doi: 10.1038/ncomms4264.
Multi-metallic nanoparticles constitute a new class of materials offering the opportunity to tune the properties via the composition, atomic ordering and size. In particular, supported bimetallic nanoparticles have generated intense interest in catalysis and electrocatalysis. However, traditional synthesis methods often lack precise control, yielding a mixture of monometallic and bimetallic particles with various compositions. Here we report a general strategy for synthesizing supported bimetallic nanoparticles by atomic layer deposition, where monometallic nanoparticle formation is avoided by selectively growing the secondary metal on the primary metal nanoparticle but not on the support; meanwhile, the size, composition and structure of the bimetallic nanoparticles are precisely controlled by tailoring the precursor pulse sequence. Such exquisite control is clearly demonstrated through in situ Fourier transform infrared spectroscopy of CO chemisorption by mapping the gradual atomic-scale evolution in the surface composition, and further confirmed using aberration-corrected scanning transmission electron microscopy.
多金属纳米粒子构成了一类新材料，通过组成、原子有序性和尺寸来调整其性能。特别是，负载型双金属纳米粒子在催化和电催化方面引起了极大的兴趣。然而，传统的合成方法通常缺乏精确的控制，导致形成了各种组成的单金属和双金属颗粒的混合物。在这里，我们报告了一种通过原子层沉积合成负载型双金属纳米粒子的通用策略，其中通过选择性地在主金属纳米粒子上而不是在载体上生长第二金属来避免单金属纳米粒子的形成；同时，通过调整前驱体脉冲序列，精确控制了双金属纳米粒子的尺寸、组成和结构。通过原位傅里叶变换红外光谱法对 CO 的化学吸附进行映射，以揭示表面组成的逐渐原子尺度演化，从而清楚地证明了这种精密控制，进一步使用校正像差的扫描透射电子显微镜进行了确认。
