CAS: Voltage-Driven Molecular Catalysis

Cuny Queens College, Flushing NY

Investigators

Abstract

With support from the Chemical Catalysis (CAT) Program of the Chemistry Division, Professors Michael Mirkin and Guoxiang Hu of the City University of New York, Queens College are using electrochemical techniques in combination with theoretical and computational approaches to investigate voltage-driven molecular catalysis. Improved understanding of voltage-driven molecular catalysis can facilitate the development of next-generation hybrid catalysts with important implications for both energy technology and synthetic chemistry. The project is also providing training opportunities for graduate and undergraduate students, who will receive multidisciplinary research training in electrocatalysis, scanning probe microscopy, computational chemistry, and nanoscience. Outreach involving high school students is planned to introduce them to the scientific approach, in general, and to catalysis and energy science in particular. In this project, Professors Michael Mirkin and Guoxiang Hu of the City University of New York, Queens College will study the fundamentally important and incompletely understood effect of the interfacial potential drop on activity of a surface-bound molecular catalyst. Hybrid voltage-driven molecular catalysts are being developed for several fundamentally important energy-related processes, such as the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) and oxidations of H2O2 and alcohols. Different redox mediators, including a fully organic molecular catalyst, TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxyl], will be attached to the catalytically inert carbon surface and the effects of chemical nature of the catalyst, solution ionic strength, and other factors on reaction kinetics will be investigated. Scanning electrochemical microscopy (SECM) will be used to measure catalytic rate constants as a function of the applied potential. The concept of voltage-driven molecular catalysis is also to be applied to electrosynthesis. A voltage-driven molecular catalyst can facilitate electrosynthetic reactions, which it has no capacity to catalyze without field assistance. The effects of the applied potential, solvent, and other experimental factors on the reaction yield and selectivity will be investigated. First-principles electronic structure calculations based on density-functional theory (DFT) will be performed to help elucidate details of the mechanism of voltage-driven molecular catalysis. 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.