The origin of the catalytic efficiency and the plasmonic optical properties of different types of hollow nanostructures

在这个由化学系大分子、超分子和纳米化学项目资助的项目中，乔治亚理工学院的Mostafa El-Sayed教授开发了纳米颗粒作为催化剂。纳米粒子是包含数千个原子的微小粒子。虽然它们比化学分子大得多，而化学分子只包含几个原子，但纳米粒子比肉眼可以看到的固体材料小得多。纳米粒子的不寻常之处还在于，大部分原子位于或非常接近表面，因此，纳米结构比与相同气体或液体接触的大块固体更容易在粒子中与大气或周围液体进行重排，交换和添加原子，因为原子通常位于固体内部，无法接近。纳米粒子具有非常大的表面积，可以进行催化化学反应，可用于快速化学生产、可持续能源和材料化学等众多领域。El-Sayed教授开发了超快的方法来制造相同或更好的材料。这些方法可以大大提高材料的生产速度，并产生新的方法来制造具有实际意义的新产品。这个项目为研究生提供了研究机会。它还包括通过与传统黑人学院和大学（HBCUs）的互动，针对代表性不足群体成员的外展活动。在这个项目中，纳米催化剂的形状、大小和组成与小等离子体纳米粒子被设计，以优化其催化性能。这些新设计的等离子体纳米微粒的光学和催化性能正在进行理论和实验研究。利用表面增强拉曼光谱（SERS）研究了纳米化合物催化反应的机理。这种方法可以区分几种可能导致催化增强反应的效应。该项目还研究了纳米龟内部颗粒的运动方式，并将它们的催化效率与气相反应进行了比较。研究小组还制备了半导体-金属混合纳米颗粒，利用超快光谱技术研究了它们的催化性能和载流子行为，并检验了它们的机械稳定性。

In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Mostafa El-Sayed of the Georgia Institute of Technology develops nanoparticles as catalysts. Nanoparticles are tiny particles that contain thousands of atoms. While they are much larger than chemical molecules, which contain only a few atoms, nanoparticles are smaller than solid materials that are large enough to see with the naked eye. Nanoparticles are also unusual in that a large fraction of the atoms are at or very near the surface, so rearrangement, exchange and addition of atoms in the particle with the atmosphere or a surrounding liquid is much easier for a nanostructure than for a bulk solid in contact with the same gas or liquid, where the atoms are typically inside the solid and not accessible. Nanoparticles have very large surface areas where catalytic chemical reactions take place, and can be used in numerous fields such as fast chemical production, sustainable energy, and material chemistry. Professor El-Sayed develops ultrafast methods to make the same or better material. These methods can greatly increase the rate of production of material and lead to new ways to make new products of practical importance. This project provides research opportunities for graduate students. It also includes outreach activities aimed at members of underrepresented groups through interactions with Historically Black Colleges and Universities (HBCUs). In this project, the shape, size, and composition of nanorattle catalysts with small plasmonic nanoparticles are engineered to optimize their catalytic performance. The optical and catalytic properties of these newly designed plasmonic nanorattles are being studied both theoretically and experimentally. The mechanisms involved in the catalytic reactions involving nanorattles are probed using surface-enhanced Raman spectroscopy (SERS). This methods allows the distinction between several possible effects that could lead to catalytic enhancement of the reactions. The project also examines how the interior particles in the nanorattles move, and compares their catalytic efficiency with gas phase reactions. The research team also prepares semiconductor-metal hybrid nanoparticles to study their catalytic properties and charge carrier behavior using ultrafast spectroscopy, and examines their mechanical stabilities.