(191a) Revisiting Electrochemical CO2 Reduction on Copper: Reaction Mechanisms Revealed By Embedded Correlated Wavefunction Theory | AIChE

(191a) Revisiting Electrochemical CO2 Reduction on Copper: Reaction Mechanisms Revealed By Embedded Correlated Wavefunction Theory

Authors 

Zhao, Q. - Presenter, Princeton University
Martirez, J. M. P., Princeton University
Carter, E. A., Princeton University
Electrochemical CO2 reduction (CO2R) to energy-rich hydrocarbons and oxygenates could contribute to sustainable fuel generation, yet efficient electrocatalysts for this reaction still do not exist. Elucidating the reaction mechanism on the best metal catalyst identified so far (copper) could aid in the discovery and design of better electrocatalysts by pinpointing bottlenecks for activity and selectivity. Because in situ electrochemical mechanism determination by experimental techniques remains out of reach, such mechanistic analysis typically is conducted using density functional theory (DFT). The DFT exchange-correlation approximations most often used to model such reactions unfortunately engender a foundational error, predicting the wrong adsorption site for CO (a key CO2R intermediate) on metal surfaces (including copper), casting doubt on previous DFT-predicted CO2R kinetics. Our work here rigorously re-examines mechanisms of CO2R on copper, by means of state-of-the-art embedded correlated wavefunction (ECW) theory, which regionally corrects for errors inherent in DFT approximations. We will present ECW-predicted kinetics of the critical CO reduction step via both potential-independent surface hydrogen transfer and potential-dependent proton-coupled electron transfer, as well as C-C bond formation toward C2 products on copper. Our work demonstrates for the first time that with rigorous ECW theory, one can properly describe electrochemistry and unearth chemical insights out of reach of experiments while predicting observables (reaction energies and barriers) fully consistent with experiments, unlike with standard DFT.