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，阿拉巴马大学的伊丽莎白·T·帕皮什、密西西比大学的贾里德·H·德尔坎普和密西西比州立大学的查尔斯·埃德温·韦伯斯特将研究将温室气体二氧化碳转化为具有新型结构的金属催化剂的合成燃料。设想未来阳光驱动的能源基础设施需要高效和坚固的催化剂，能够为人工光化学驱动的反应提供动力，以生产燃料。与我们目前依赖化石燃料的基础设施相比，利用阳光创造燃料作为按需提供的储存化学能源是有吸引力的。尽管如此，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，理想地使用容易获得和负担得起的金属。目前缺乏这种催化剂，这是目前知识基础中的一个重大缺口。研究人员将设计新的催化剂，用于将二氧化碳还原为燃料，其创新结构以前从未经过测试。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，并最终导致以碳中性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训10-15名本科生和研究生。调查人员将访问当地学校进行外联活动，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中进行催化反应，结果将与社区共享，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，阿拉巴马大学的伊丽莎白·T·帕皮什教授和她的合作者，密西西比大学的贾里德·H·德尔坎普和密西西比州立大学的查尔斯·埃德温·韦伯斯特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减少二氧化碳。旨在将二氧化碳转化为燃料或燃料前体的人工光化学方案需要更高效、更坚固和更有选择性的催化剂。利用在水中保持活性的高效自敏化催化剂的合成和测试方面的先前经验，合作团队将致力于使用两种策略设计新的坚固耐用的催化剂：通过使用大环钳形配体来分离活性中心，通过使用低价金属来分离低配位金属络合物。合成、机理和计算方面的研究将朝着三个目标进行：(1)增加对数控钳形连接的第一排金属催化剂的了解；(2)扩展对未被开发的具有Ir光敏剂的超分子催化剂的了解；(3)了解连接到半导体电极上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一种耐用的、地球上富含金属的催化剂系统，用于在太阳能光电化学电池中光催化还原二氧化碳和分解水。系统地将这些想法应用于第一排金属在很大程度上仍是一个未知的领域，潜在的回报是了解如何用第一排金属络合物制造太阳能燃料。科学成果将通过出版物、演示文稿和专利进行交流；更广泛的影响将包括在本科教学实验室中的外展活动和催化研究实验。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.