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

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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.