Reduced colloidal metal-oxide nanocrystals as novel redox reagents

华盛顿大学的James M.Mayer得到了大分子、超分子和纳米化学计划颁发的合作研究奖的支持，该研究旨在研究含有额外电子的胶体氧化物半导体纳米颗粒的化学反应活性和物理性质。我们将研究不同尺寸、不同带隙、不同表面覆盖基团的纯和掺杂的氧化锌和二氧化钛纳米颗粒。光激发这些粒子，然后捕获空穴，得到还原的纳米粒子的稳定解决方案，这些纳米粒子包含导带轨道上的电子或处于“陷阱态”的电子。合成、分析和光谱技术将被整合在一起，以发展对支配这些纳米颗粒反应性的结构/功能关系的基本理解。纳米粒子的充电化学将通过跟踪空穴捕获时形成的有机产品和质子，以及通过光谱跟踪光激发纳米粒子的演变来进行检查。将使用分子和纳米晶体底物来检验还原粒子执行多电子/多质子反应的能力。研究了纳米晶掺杂和表面改性对薄膜性能的影响。还将发展还原粒子的光谱、热化学和动力学性质之间的联系。这项研究将产生新的基础性科学见解，可能改变对此类材料的理解和在各种技术中的应用，包括光电化学电池或电池的氧化物/溶液界面。这项研究将研究金属氧化物纳米结构的基本反应性。这种纳米结构在能量转换、能量存储和光催化技术中普遍存在，从拟议的研究中收集的信息将对这些技术产生广泛的影响。该项目还可以进一步开发廉价、坚固和对环境无害的具有可调潜力的多电子还原试剂，应用于从基础研究到催化的各种科学背景。最后，这项研究将为一般的电子转移化学提供新的基础见解，并将加深我们对这类重要反应的理解。除了产生新的基本科学见解和新材料外，这项研究还将为本科生和研究生提供高级跨学科教育和培训的机会，为他们未来的科学和工程职业生涯做好准备。将通过让本科生参与研究、将研究中的实验和概念纳入本科实验室课程、与本科院校的教职员工和学生合作以及在地区社区学院和高中开展外联活动，将重点放在本科生一级的研究和教育一体化上。

James M. Mayer of the University of Washington is supported by an award from the Macromolecular, Supramolecular and Nanochemistry Program in collaborative research that seeks to examine the chemical reactivities and physical properties of colloidal oxide semiconductor nanoparticles containing extra electrons. Pure and doped ZnO and TiO2 nanoparticles of different sizes, band gaps, and with different surface-capping groups will be studied. Photoexcitation of these particles followed by hole trapping yields stable solutions of reduced nanoparticles, containing electrons in conduction-band orbitals or in "trap states". Synthetic, analytical, and spectroscopic techniques will be integrated to develop a fundamental understanding of the structure/function relationships that govern the reactivities of these nanoparticles. The nanoparticle charging chemistries will be examined by tracking the organic products and protons that are formed upon hole trapping, and by following the evolution of the photoexcited nanoparticles spectroscopically. The ability of the reduced particles to perform multi-electron/multi-proton reactions will be examined using molecular and nanocrystal substrates. The influence of nanocrystal doping and surface modification will be examined. Connections among the spectroscopic, thermochemical, and kinetic properties of the reduced particles will be developed. This research will yield new fundamental scientific insights that could alter the ways such materials are understood and applied in various technologies including the oxide/solution interfaces of photoelectrochemical cells or batteries.This research will address fundamental reactivities of metal-oxide nanostructures. Such nanostructures are ubiquitous in energy conversion, energy storage, and photocatalysis technologies, and the information gleaned from the proposed research will have broad implications in each of these technologies. This project could furthermore result in the development of inexpensive, robust, and environmentally sound multi-electron reducing reagents with tunable potentials for application in a variety of scientific contexts from fundamental research to catalysis. Finally, this research will provide new fundamental insights into general electron transfer chemistries and will deepen our understanding of this important class of reactions. In addition to yielding new fundamental scientific insights and new materials, this research will also provide undergraduate and graduate students with opportunities for advanced interdisciplinary education and training to prepare them for future careers in science and engineering. Emphasis will be placed on integration of research and education at the undergraduate level through involvement of undergraduates in the research, incorporation of experiments and concepts from the research into the undergraduate laboratory curriculum, collaboration with faculty and students from undergraduate institutions, and outreach activities at regional community colleges and high schools.