Meeting of the Princeton ACS Section
(June 7 Meeting Rescheduled)
Tuesday, June 13, 2023
Professor Andrew Bocarsly
Department of Chemistry, Princeton University
“An Insulator, a Dirty Carbon Surface, and the Electrocatalytic Formation of True Organics from CO2: Not a Textbook Synthesis”
Frick Chemistry Laboratory, Taylor Auditorium, Princeton University
Mixer (in Atrium) 6:30 pm; Lecture 7:00 pm
Abstract A binary mixture of chromium oxide and gallium oxide on a glassy carbon electrode that is tainted with a trace of nickel provides a new heterogeneous electrocatalyst for the reduction of CO2 to organic products. Unlike most electrocatalysts, which are based on metal layers that only generate C1 products, this mixed metal oxide system forms a variety of C2 – C4 products in unprecedented yield (~70% faradaic efficiency). Most interestingly, we find that the nickel metal enhanced Cr2O3/Ga2O3 interface efficiently catalyzes the formation of 1-butanol with greater than 40% faradaic efficiency in aqueous electrolyte. A variety of other C2, C3 and C4 products are also observed. These species can be selected for, by regulating the electrolyte pH, and the electrode potential.
The overall faradaic efficiency of this electrocatalytic system and its ability to couple carbons is unprecedented. However, the mechanism by which this occurs is somewhat mysterious. By any type of normal chemical construction this system should not be a CO2 electrocatalyst!
• First, coupling of CO2 molecules to make C2+ products typically requires a copper based electrode.
• Second, the oxides involved are insulators – this is not normally considered a route to electrocatalysis!
• Third, the reduction of CO2 to butanol is a 24e– process. How, can this occur at any electrode interface?
Over the past year, we have explored these issues. This talk will endeavor to resolve the mysteries noted above by considering the role of electrocatalyst nanostructure and chemical heterogeneity in the overall chemical mechanism. Additionally, we invoke a novel mechanistic route based on the synthesis of a formate intermediate, circumventing the need to generate CO, the “preferred” intermediate in C2+ electrocatalysis.
A detailed mechanistic understanding of these systems is likely to offer new opportunities for the electrosynthesis of organic products and provide pragmatic routes to organic feedstocks from CO2.
Biography: Andrew Bocarsly received his Bachelor of Science degree in chemistry and physics from UCLA in 1976, and his Ph.D. in chemistry from M.I.T. in 1980. He has been a member of the Princeton University, Chemistry Department for forty-three years. Professor Bocarsly has published over 250 papers and patents. Research in his laboratory is focused on electrochemistry and photochemistry for the conversion of carbon dioxide to fuels and feedstocks, as well as the materials chemistry of cyanometallate systems.
Professor Bocarsly serves as a consultant to various alternate energy companies. He co-founded Liquid Light Inc. He has edited a volume for Structure and Bonding in the area of fuel cells and batteries, and served as the electrochemistry editor for Methods in Materials Research. He currently sits on the editorial advisory board of the Journal of CO2 Utilization, and the Science Board of the International Conference on Carbon Dioxide Utilization (ICCDU).
Professor Bocarsly has received an Alfred P. Sloan Fellowship, the Sigma Xi (Princeton Section) Science Educator Award, and the American Chemical Society-Exxon Solid State Chemistry awards
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