BICEPS

Carbon Dioxide (CO2) is a renewable feedstock for the production of chemicals and energy-rich fuels. Its transformation is however challenging because if its chemical inertness. There is a pressing need for the development of efficient, robust, and economically viable CO2-reduction catalysts. In this BICEPS program, we aim to develop molecular systems based on Earth abundant elements for use in reducing CO2 to CO, a high-value molecule, using visible light as the primary energy source. There are few efficient molecular photocatalytic systems based entirely on non-noble metals. We aim to fill this gap by designing and synthesizing molecular photocatalysts based on Cu and Ni coordination complexes. Built on our prior accomplishments, homoleptic Cu(I)-phenanthroline complexes and macrocyclic Ni(II) complexes are chosen as model photosensitizers (PS) and molecular catalysts (MC), respectively, which will be effectively coupled by covalent linkers. We hypothesize that the rational design of the covalent linkers uniting PS and MC will enable the tuning of photo-induced charge separation and multi-electron CO2 reduction steps. Our hypothesis will be tested by the following research tasks: - Preparing a set of PS-Linker-MC dyads based only on Earth abundant elements where molecular structures of the linkers between PS and MC will be varied systematically; - Studying the structures and photocatalytic properties of the PS-Linker-MC systems; - Investigating photocatalytic mechanisms using a combination of in-situ infrared spectroelectrochemistry, and time-resolved X-ray absorption spectroscopies. This project highlights an international collaboration between the CEISAM Lab at Nantes University in France and the Photocatalysis Group at the University of New Hampshire (UNH) in USA. The two teams collaborate to provide complementary expertise needed for this project. In particular, the CEISAM Lab will lead on ligand synthesis and derivatization, while the UNH team will focus on photocatalysis and spectroscopic investigation. The two teams have been working together to study CO2 reduction using molecular catalysts since October 2022 after meeting at the online NSF-ANR symposium, and the collaboration has produced exciting results. Manuscripts are currently being prepared for submission to journals for publication. A graduate student from the CEISAM Lab, Julien Simonneau, visited the UNH team in September-October 2023 and acquired important skills in photocatalysis. Project BICEPS will build on the momentum to advance the fundamental understanding of molecular photocatalysis for efficient solar fuel production.