Career: Catalytic Production of H2 from Water by Molecular Metal Complexes with Pentadentate Ligands

在这个由化学学部化学催化项目资助的项目中，孟菲斯大学的赵旋教授正在开发新的催化剂，用于从水和阳光中生成氢（一种重要的化学原料和未来的燃料）。为了实现这一目标，人们正在开发以钴等具有经济吸引力的金属为基础的新型催化剂。此外，催化剂如何发挥作用的细节正在确定中。这一信息将为形成更有效的将水转化为氢的材料提供指导，并可能应用于其他潜在的应用，如减少二氧化碳。该项目包括培养催化科学方面的本科生和研究生。一个拓展项目将为孟菲斯地区的学生和教师提供参与可再生能源研究的机会，并通过周末研讨会、夏季研究机会和当地会议了解太阳能转换和光催化。本项目的中心假设是，金属离子与单一多齿配体的络合，在金属上留下一个开放的位点，将产生稳定的金属配合物，对光催化还原水具有高的催化活性。研究主要集中在钴络合物上，初步数据支持这一假设，但也包括其他地球上丰富的金属。除了旨在与各种配体形成这些配合物的合成研究外，还进行了详细的机制研究，以确定质子结合和还原的活性物质，H-H的形成是通过均溶还是异溶途径进行的，以及控制H2演化机制的一般因素。机理研究是与布鲁克海文国家实验室的研究科学家合作进行的。

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Xuan Zhao of the University of Memphis is developing new catalysts for the generation of hydrogen (an important chemical feedstock and future fuel) from water and sunlight. To accomplish this, new catalysts that are based on economically attractive metals such as cobalt are being developed. Additionally, the details of how the catalysts function are being determined. This information will provide a guide to form yet more efficient materials to convert water to hydrogen and may be applied to other potential applications such as the reduction of carbon dioxide. The project involves the training of undergraduate and graduate students in catalytic science. An outreach program will provide Memphis area students and faculty at predominantly undergraduate institutions with opportunities to participate in renewable energy research and to learn about solar energy conversion and photocatalysis through weekend workshops, summer research opportunities and local meetings. The central hypothesis of this project is that the complexation of a metal ion by a single polydentate ligand that leaves one open site on the metal will result in stable metal complexes with high catalytic activity toward the photocatalytic reduction of water. The research centers largely on cobalt complexes for which preliminary data supports the hypothesis, but includes other earth abundant metals. In addition to synthetic studies aimed at forming these complexes with a variety of ligands, a detailed mechanistic investigation is being carried out to determine the active species for proton binding and reduction, whether H-H formation occurs through a homolytic or heterolytic pathway, and the general factors that control the mechanism of H2 evolution. The mechanistic studies are being conducted in collaboration with research scientists at Brookhaven National Laboratory.