CAS: Collaborative Research: Macrocyclic and Supramolecular Pincer Catalysts Using Ruthenium and First Row Metals for Carbon Dioxide Reduction

在化学系化学催化项目的支持下，阿拉巴马大学的Elizabeth T. Papish、密西西比大学的Jared H. Delcamp和密西西比州立大学的Charles Edwin Webster将研究利用新型结构的新型金属催化剂将温室气体二氧化碳转化为合成燃料。展望未来的阳光驱动的能源基础设施，我们需要高效和强大的催化剂来为燃料生产的人工光化学驱动反应提供动力。与我们目前依赖化石燃料的基础设施相比，利用阳光作为储存的化学能制造燃料是很有吸引力的。然而，这一愿景需要快速、耐用和选择性的催化剂，在可行的情况下，这些催化剂将理想地利用容易获得和负担得起的金属。目前这种催化剂的缺乏代表了当前知识库中的一个重大缺口。研究人员将设计新的催化剂，以减少二氧化碳的排放，并采用以前未经测试的创新结构。他们将通过合成、机械和计算研究，通过设计强大和高活性的催化剂来控制和理解二氧化碳的减少。这些研究可以阐明影响催化作用的因素，并最终导致以碳中和的方式从温室气体中生产太阳能燃料。这项研究的结果将被广泛分享，该项目预计将在项目期间帮助培养10-15名本科生和研究生。调查人员将访问当地学校，开展拓展活动，并在他们的研究实验室接待高中生。此外，本科生将在教学实验室环境中进行催化反应，并将结果与社区分享，以提供教育经验和实验验证。在化学系化学催化项目的支持下，阿拉巴马大学的Elizabeth T. Papish教授和她的合作者，密西西比大学的Jared H. Delcamp和密西西比州立大学的Charles Edwin Webster，将研究用含有第一排过渡金属和大环配体的新型金属催化剂来减少二氧化碳。在将二氧化碳转化为燃料或燃料前体的人工光化学方案中，需要更高效、更稳定、更有选择性的催化剂。利用之前合成和测试在水中保持活性的高效自敏催化剂的经验，合作团队将采用两种策略设计新的强大催化剂：通过使用大环钳形配体隔离活性位点，以及通过使用低价金属低配位金属配合物。合成、机械和计算研究将针对三个目标：(1)增加对cnc钳连接的第一行金属催化剂的理解，(2)扩展对未开发的铱光敏剂超分子催化剂的知识，以及(3)了解与半导体电极连接的均相催化剂的行为。长期目标是利用在上述任务中获得的知识，使分子催化剂设计领域更接近于持久的，地球上丰富的金属基催化剂系统，用于光催化还原二氧化碳，并在太阳能光电电化学电池中分解水。将这些想法系统地应用于第一行金属在很大程度上仍然是未知的领域，潜在的回报是了解如何用第一行金属复合物制造太阳能燃料。科学成果将通过出版物、演讲和专利进行传播；更广泛的影响将包括推广活动和催化研究实验在本科教学实验室设置。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Catalysis program in the Division of Chemistry, Elizabeth T. Papish of The University of Alabama, Jared H. Delcamp of The University of Mississippi, and Charles Edwin Webster of Mississippi State University will study the transformation of the greenhouse gas carbon dioxide into synthetic fuels with new metal catalysts of novel structure. Envisioning a sunlight-driven energy infrastructure in our future requires efficient and robust catalysts that can power artificial photochemically driven reactions for fuel production. Using sunlight to create fuels as stored chemical energy available on demand is attractive relative to our current fossil fuel-reliant infrastructure. Nonetheless, this vision requires fast, durable, and selective catalysts that would ideally utilize readily available and affordable metals where feasible. The current lack of such catalysts represents a significant gap in the current knowledge base. The investigators will design new catalysts for carbon dioxide reduction to fuels with innovative structures previously untested. They will work on controlling and understanding carbon dioxide reduction through design of robust and highly active catalysts via synthetic, mechanistic, and computational studies. These studies can elucidate the factors that impact catalysis and eventually lead to the production of solar fuels from a greenhouse gas in a carbon neutral fashion. The results of this research are to be shared broadly, and this project is expected to help train a diverse group of 10-15 undergraduate and graduate students over the project period. The investigators will visit local schools for outreach events and host high school students in their research laboratories. In addition, undergraduate students will perform catalytic reactions in a teaching lab setting, and the results will be shared with the community, to offer educational experiences along with experiment verification.With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Elizabeth T. Papish of The University of Alabama, and her collaborators, Jared H. Delcamp of The University of Mississippi, and Charles Edwin Webster of Mississippi State University, will study carbon dioxide reduction with new metal catalysts containing first row transition metals and macrocyclic ligands. More efficient, robust, and selective catalysts are needed for artificial photochemical schemes aimed at converting carbon dioxide to fuels or fuel precursors. Using prior experience in the synthesis and testing of efficient self-sensitized catalysts that retain activity in water, the collaborative team will work on designing new robust catalysts using two strategies: active site isolation via use of a macrocyclic pincer ligand, and low-coordinate metal complexes via the use of low-valent metals. Synthetic, mechanistic, and computational studies will be directed toward three goals: (1) to increase the understanding of CNC-pincer ligated first-row metal catalysts, (2) to expand the knowledge of under-explored supramolecular catalysts with iridium photosensitizers, and (3) to understand the behavior of homogeneous catalysts linked to semiconductor electrodes. The long-term goal is to move the field of molecular catalyst design closer to a durable, earth-abundant metal-based catalyst system for the photocatalytic reduction of carbon dioxide coupled to water splitting in a solar powered photo-electrochemical cell using the knowledge gained in the above tasks. Applying these ideas systematically to first-row metals is still largely uncharted territory, with the potential payoff being understanding how to make solar fuels with first row-metal complexes. The scientific results will be communicated through publications, presentations, and patents; the broader impacts will include outreach events and catalysis research experiments in an undergraduate teaching laboratory setting.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.