(267a) Modeling the Electrochemical Double Layer - CO2 Reduction On Pt(111)

Electrochemical CO2 reduction is one promising method for generating sustainable hydrocarbons through the use of renewable energy sources. Many catalysts have been examined for their ability to reduce CO2 to hydrocarbons such as methane and ethylene, but metallic copper remains the best at doing so with good faradaic efficiency.  The high overpotential of copper for this conversion (more than 1eV negative of the thermodynamic requirement of +0.17V vs. RHE), however, drives ongoing research to understand how to design a better catalyst. 

Understanding the mechanism of CO2 reduction is key in building an accurate microkinetic model that can be used to describe CO2 reduction on surfaces. Intermediate steps along the CO2 reduction pathway can broadly be classified into proton-electron transfers and surface reactions.  This work focuses on the kinetic barriers involved in proton-electron transfer reactions along the CO2 reduction pathway. 

By explicitly modeling a water layer above a Pt(111) surface with CO2 reduction intermediates adsorbed, transition states for proton-electron transfers in an electrochemical environment can be found.   Kinetic barriers for *CO to *COH, *COH to *C, and *CO2 to *COOH were all found to be small (<0.2 eV additional barrier) in systems where the work function changed by <1 eV.