Catalysis by Shape Selected Metallic Nanoparticles: Mechanism of Shape Control and Nanoparticle Stability

该项目在分析和表面化学计划的支持下，重点研究了通过氢还原和通过封端聚合物控制颗粒形状的过程制备的过渡金属纳米颗粒的表征。 El-Sayed和Wang教授以及他们在格鲁吉亚理工学院的学生将使用高分辨率透射电子显微镜、平行探测电子能量损失光谱、能量色散X射线光谱、拉曼和FTIR振动光谱来表征这些纳米颗粒的形状和组成。 我们的目标是建立控制这些纳米粒子的形状和它们的属性的合成参数的理解。 这项工作的长期目标是开发有用的纳米颗粒结构，用于多相催化。 格鲁吉亚理工学院的El-Sayed教授和Wang教授开发了一种新的合成工艺，用于制备可以控制形状的过渡金属纳米颗粒。 该过程涉及在覆盖颗粒表面的聚合物存在下使用分子氢还原金属离子。 在控制这些颗粒的尺寸、形状和组成方面很重要的因素将使用一系列表面表征方法，特别是高分辨率透射电子显微镜来确定。 这项工作的长期目标是开发一系列新的工业用低温多相催化剂。

This project, supported in the Analytical and Surface Chemistry Program, focusses on the characterization of transition metal nanoparticles prepared by a process involving hydrogen reduction and control of particle shape by the presence of capping polymers. Professors El-Sayed and Wang and their students at Georgia Tech will characterize the shape and composition of these nanoparticles using high resolution transmission electron microscopy, parallel- detection electron energy-loss spectroscopy, energy-dispersive X- ray spectroscopy, and Raman and FTIR vibrational spectroscopies. The objective is to establish an understanding of the synthetic parameters that control the shapes of these nanoparticles and their properties. The long-term aim of this work is to develop useful nanoparticle structures for applications in heterogeneous catalysis. A new synthetic process for preparing transition metal nanoparticles that can control their shape has been developed by Professors El-Sayed and Wang at Georgia Tech. This process involves reduction of metal ions using molecular hydrogen in the presence of polymers that cap the particle surface. The factors that are important in controlling the size, shape, and composition of these particles will be determined using an array of surface characterization methods, particularly high resolution transmission electron microscopy. The long-term goal of this work is to develop a family of new low temperature heterogeneous catalysts for industrial use.