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

该项目由分析和表面化学项目支持，重点研究过渡金属纳米颗粒的表征，该纳米颗粒是通过氢还原和覆盖聚合物控制颗粒形状的过程制备的。El-Sayed教授和Wang教授以及他们在佐治亚理工学院的学生将利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、拉曼光谱和FTIR振动光谱来表征这些纳米颗粒的形状和组成。目的是建立对控制这些纳米颗粒形状及其性质的合成参数的理解。这项工作的长期目标是开发用于多相催化的有用纳米颗粒结构。佐治亚理工学院的El-Sayed教授和Wang教授开发了一种新的合成工艺，用于制备可以控制其形状的过渡金属纳米颗粒。该工艺涉及在覆盖颗粒表面的聚合物存在的情况下，使用分子氢来减少金属离子。控制这些颗粒的大小、形状和组成的重要因素将通过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。本工作的长期目标是开发一系列新的工业用低温非均相催化剂。

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.