Systematic investigations of the surface properties of metal nanoparticles and their applications

了解和调整纳米材料（1纳米= 10亿分之一米）如纳米粒子（NPs）的性质对纳米科学技术的发展起着至关重要的作用。由于所谓的量子尺寸效应和表面效应，NPs的性质与它们的体对应物有很大的不同。量子尺寸效应主要是由于材料的电子被限制在纳米尺寸的几何结构中，其中量子力学起主要作用。因此，NPs的性质往往与尺寸有关。表面效应是由于NPs的表面体积比大。因此，适当改变NPs的表面环境将导致其性质的显著变化。在NPs的各种性质中，了解与表面相关的性质是至关重要的，但也是非常困难的，这主要是由于化学合成高质量NPs的挑战，即具有单分散尺寸和适当的表面化学，尺寸和组成的NPs，以及研究NPs表面性质的技术挑战。在我提出的研究的第一个领域，将致力于系统地研究金属NPs的表面特性，重点是克服上述化学合成和表征方法方面的挑战。广泛的高质量的金属NPs具有适当定制的表面化学，合金成分和粒度将使用一种新的合成方法合成。然后，将开发各种基于表面敏感同步加速器的光谱学方法，包括现有的和新的方法，并用于获得NP系统表面特性的整体物理图像。本文将提出基于纳米粒子表面特性的两个方面的新应用。

Understanding and tuning the properties of nanomaterials (1 nanometer = 1 billionth meter) such as nanoparticles (NPs) play a crucial role in the development of nanoscience and technology. The properties of NPs are dramatically different from their bulk counterpart due to the so-called quantum-size effect and surface effect. The quantum-size effect is mainly caused by the confinement of electrons of the materials in a nano-sized geometry where the quantum mechanics play a predominant role. As a result, properties of the NPs are often size-dependent. The surface effect is due to the large surface-to-volume ratio of NPs. As a consequence, appropriate modifications of the surface environment of NPs will result in significant changes in their properties.  Among the various properties of NPs, understanding the surface-relevant properties is of fundamental importance and yet very difficult mainly due to the challenge in the chemical synthesis of high quality NPs, i.e. NPs with monodisperse size and properly tailored surface chemistry, size and composition and the technical challenge in studying the surface properties of NPs. In the first area of my proposed research, significant efforts will be devoted to systematically investigating the surface properties of metal NPs with the emphasis on overcoming the above-mentioned challenges in chemical synthesis and characterization methodology. A broad range of high-quality metal NPs with properly tailored surface chemistry, alloy composition and particle size will be synthesized using a novel synthetic method. Then a variety of surface-sensitive synchrotron-based spectroscopy methods, including both existing and novel ones, will be developed and used to obtain a whole physical picture of the the surface properites of the NP systems. Two aspects of novel applications based on the surface properties of NPs will be proposed.