CAS: Bidirectional Molecular Catalysts to Control Dinitrogen Reduction and Ammonia Oxidation

Montana State University, Bozeman MT

Investigators

Abstract

With the support of the Chemical Catalysis program in the Division of Chemistry, Michael Mock of Montana State University is studying ways to store energy by developing metal catalysts to convert dinitrogen gas found in air to a fuel such as ammonia. Understanding the transformation between nitrogen and ammonia offers a potential carbon-free fuel cycle to interconvert chemical and electrical energy. The project will focus on the synthesis of new catalysts using inexpensive metals such as chromium, iron, and nickel. By design, the novel behavior of these catalysts will be used to both form ammonia and convert ammonia to nitrogen. The project will establish strategies for the interconversion of nitrogen and ammonia by removing and attaching hydrogen atoms using chemical reagents, electricity, and/or light energy in conjunction with the metal catalysts. Additionally, the Mock group will host Native American undergraduate students from Montana Tribal Colleges to work in the laboratory to learn about synthetic chemistry and catalysis, and to acquire hands-on laboratory skills. Providing hands-on experience in chemistry to Native American students will serve to increase the involvement of underrepresented minorities in chemistry and will contribute to strengthening the technical workforce in Montana and in the United States. This project will enable outreach activities at area primary and secondary schools to engage students on the topics of renewable forms of energy and new energy technologies. Science outreach activities at area schools will engage students on the topics of renewable forms of energy and new energy technologies that have a positive impact on the environment and society. Under this project, Professor Michael Mock of Montana State University is studying molecular catalytic systems to develop a nitrogen-based cycle to store and utilize energy in N–H bonds. Catalysts using chromium and iron will be designed for the interconversion of dinitrogen (N2) and ammonia (NH3). The project will likely lead to a better mechanistic understanding of H-atom transfer reactions of the same catalyst for both N2 reduction and NH3 oxidation. hence assessing the concept of microscopic reversibility for two challenging multi-proton, multi-electron reactions involving making and breaking N–N and N–H bonds. A common strategy of delivery of H-atoms to N2 and the removal of H-atoms from NH3 ligands will be accomplished by using chemical reagents, electrocatalytic conditions, and/or light energy. The project will measure thermodynamic N–H bond strengths and characterize metal-NxHy intermediates to advance catalyst design. The proposed work will use Ni-based platforms for understanding homolytic N–H bond cleavage and N–N coupling steps en route to dinitrogen formation. 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.