Collaborative Research: Atomistic Switches on Pyridinol Based Pincer Ligated Catalysts for Carbon Dioxide Reduction

在化学部门催化项目的资助下，塔斯卡卢萨阿拉巴马大学的伊丽莎白·帕比什博士、密西西比大学的贾里德·德尔卡普博士和密西西比州立大学的查尔斯·埃德温·韦伯斯特博士正在进行合作研究，设计新的催化剂，利用阳光将二氧化碳（燃料燃烧产生的温室气体）转化为一氧化碳（燃料前体）。将二氧化碳转化为一氧化碳的能力是具有挑战性的，这是利用阳光从二氧化碳中制造柴油燃料战略的重要一步。这种转换可能对确保美国能源的未来很有用，因为它可以提供一种替代石油储备的手段，因为它们已经耗尽了。此外，太阳能燃料的形成加上燃料燃烧可以被认为是碳中性的，因为这个过程不会向大气中增加二氧化碳。研究小组正在使用合成化学来制造新的催化剂，测试这些催化剂，并通过计算优化和理解这一过程中的关键步骤。关键的创新在于理解催化剂上小而远的基团的变化是如何影响反应过程的。这个项目使用的金属是地球丰富的和无毒的，使化学反应更可持续和环保。这个项目在阿拉巴马州和密西西比州的大学里培养了一批多样化的研究生和本科生。这种协同合作增强了这些小组中学生的学习体验。这个天主教组织正在开展外展活动，包括在阿拉巴马大学举办的“化学职业”研讨会，以及在附近一所小学举行的科学示范，以吸引学生参与STEM教育。Drs。Papish， Delcamp和Webster结合了有机金属合成和机械研究，光驱动催化和利用太阳能以及有机金属计算化学方面的各种专业知识。他们的团队正在设计、测试和研究新的催化剂，这些催化剂带有钳形配体，其外围带有氧基取代基，与贵金属和富含地球的金属结合在一起。这些研究小组正在阐明配体上的远端氧基取代基的质子化状态如何改变这些配合物的催化剂寿命、反应速率和选择性。通过了解电子给体基团如何影响质子耦合电子转移（PCET）并降低催化过程的能量需求，这些团队正在设计高度耐用和活性的催化剂。该团队正在采用一种迭代的、机械的方法，在合成、催化和计算研究之间进行反馈，从而开发出高活性、耐用的催化剂。这些催化剂也被集成到一个完整的光电化学电池中，其中二氧化碳还原与水氧化相结合。这个项目在项目期间培养了一群不同的本科生和研究生。Papish博士每年在阿拉巴马大学主持“化学职业”研讨会。她和她的团队还访问了当地的小学，进行示范，并与学生们讨论科学的机会。为了将催化化学的研究引入教学实验室，我们也在为本科化学实验室开发新的实验。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 funding from the Catalysis Program of the Chemistry Division, Dr. Elizabeth Papish of the University of Alabama at Tuscaloosa, Dr. Jared Delcamp of the University of Mississippi, and Dr. Charles Edwin Webster of Mississippi State University are engaged in collaborative research designing new catalysts that can harness sunlight to convert carbon dioxide, a greenhouse gas leftover from fuel combustion, into carbon monoxide, a fuel precursor. The ability to convert carbon dioxide to carbon monoxide is challenging, and is an important step in a strategy to harness sunlight to make diesel fuel from carbon dioxide. This conversion may become useful for securing the energy future of the US, as it can provide a means to replace oil reserves as are they are depleted. Furthermore, solar fuel formation coupled with fuel combustion can be considered carbon neutral, as this process does not add carbon dioxide to the atmosphere. The research team is using synthetic chemistry to make new catalysts, test those catalysts, and computationally optimize and understand the critical steps in this process. The key innovation has been understanding how changes to small, remote groups on the catalyst can influence the course of the reaction. This project uses metals that are earth abundant and non-toxic making the chemical reactions more sustainable and environmentally friendly. This project is training a diverse group of graduate and undergraduate students at universities in Alabama and Mississippi. This synergistic collaboration enhances the learning experience for the students in these groups. The Papish group is conducting outreach events, including "Careers in Chemistry" seminars at the University of Alabama and science demonstrations at a nearby elementary school to engage students in STEM education. Drs. Papish, Delcamp, and Webster combine a wide variety of expertise in organometallic synthesis and mechanistic studies, light driven catalysis and harnessing solar energy, and organometallic computational chemistry. Their groups are designing, testing, and studying new catalysts bearing pincer ligands with oxygenated substituents on the periphery that are bound to both precious and earth abundant metals. The groups are elucidating how the protonation state of the remote oxygenated substituents on the ligands alters catalyst lifetime, reaction rate, and selectivity with these complexes. By understanding how electron donor groups influence proton coupled electron transfer (PCET) and reduces the energy requirements for catalytic processes, the groups are designing highly durable and active catalysts. This team is taking an iterative, mechanistic approach with feedback between the synthesis, catalysis, and computational studies that is leading to the development of highly active, durable catalysts. These catalysts are also being integrated into a complete photoelectrochemical cell where carbon dioxide reduction is coupled with water oxidation. This project is training a diverse group of undergraduate and graduate students over the project period. Dr. Papish is hosting "Careers in Chemistry" seminars at the University of Alabama each year. She and her group are also visiting local elementary schools to perform demonstrations and discuss opportunities in science with the students. New experiments are also being developed for undergraduate chemistry labs to introduce catalytic chemistry research to the teaching lab.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.