Atomically-Dispersed Co and Cu Catalysts for Reactions Involving C-H Activation

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Hydraulic fracturing technology has dramatically increased the availability of natural gas feedstocks. This abundance of readily available domestic natural gas suggests it may be a candidate to displace petroleum in the production of commodity chemicals. Use of biomass-derived carbon resources would be an even more environmentally benign feedstock to produce commodity chemicals. Yet, the conversion of both natural gas and biomass into commodity chemicals requires a catalytic upgrading reaction, in which one molecule is selectively converted to a second desired molecule of higher value. For natural gas and biomass to be economically competitive with petroleum as a feedstock, this catalytic conversion must be both highly selective (i.e. unwanted byproducts are avoided) and inexpensive. However, most of today's catalysts use expensive precious metals, have only modest selectivity, and often require energy-intensive high temperature and pressure conditions. Development of economic catalytic processes that convert alternative chemical feedstocks into value added chemicals would benefit greatly by the discovery and engineering of new catalysts that are derived from low-cost earth-abundant elements. Recent observations suggest some atomically-dispersed, earth abundant metals on a carbon support approach the activity and selectivity of a precious metal catalyst, at much less expense. This project seeks to identify the atomic and electronic structure of isolated cobalt and copper atoms in nitrogen-loaded carbon and relate those characteristics to catalytic performance in representative catalytic reactions.This project will correlate the catalytic performance of atomically-dispersed cobalt and copper ions in nitrogen-loaded carbon to the coordination environment and chemical state of the active catalytic site. The latter will be probed with high resolution electron microscopy, in-situ X-ray absorption spectroscopy and in-situ X-ray photoelectron spectroscopy. Reactivity will be assessed via alcohol oxidative dehydrogenation and hydrocarbon dehydrogenation. Results from this study should provide structural models of the active sites and lead to generalized rules for designing and synthesizing new, highly-dispersed, earth-abundant metal atom catalysts. The project involves research training and education of undergraduate and graduate students. Collaborations with the Max Planck Institutes in Germany and two US national laboratories are part of the project.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.