Qi, LongUniversity of Minnesota Duluth. Department of Chemistry and Biochemistry2022-05-202022-05-202022https://hdl.handle.net/11299/227537Friday, February 18, 2022, 3:00 p.m.; Chem 200; Dr. Long Qi, Associate Scientist, U.S. DOE Ames Laboratory, Ames, IowaCatalytic cleavage of strong bonds including H-H, C-O, and C-H bonds is a highly desired fundamental transformation for the production of chemicals and fuels. Transition metal-containing catalysts are employed although accompanied with poor selectivity in hydrotreatment; metal-free catalysts have been reported primarily for hydrogenation and oxidative dehydrogenation. We report the nitrogen-assembly carbons (NACs) with closely-spaced graphitic nitrogen as active sites, as the first metal-free catalyst achieving room temperature dihydrogen dissociation and subsequent application in the transformation of bio-derived oxygenates (Nat. Commun. 2020, 11, 4091). NACs exhibit high selectivity towards alkylarenes for hydrogenolysis of aryl ethers as model bio-oxygenates without over-hydrogeneration of arenes. Various kinetic and mechanistic experiments were carried out to demonstrate the assemblies of graphitic N are the active sites supported by DFT calculations. Isotope labeling studies further reveal the cleavage of C-OH is achieved by the formation of reversible C-Nsurf bond as in the chemisorbed species. Moreover, we further show that NAC catalysts are versatile for activating heterocycles as liquid organic hydrogen carriers (LOHCs) to release hydrogen (Sci. Adv. 2022, 8, eabl9478). The discovery of nitrogen assembly as active sites can open up broad opportunities for rational design of new metal-free catalysts for challenging chemical reactions to meet the challenges for a carbon-neutral future.en-USPostersUniversity of Minnesota DuluthSeminarsDepartment of Chemistry and BiochemistryOther