Electrocatalytic reduction of CO2 to alcohols would provide a synthetic sustainable way to convert renewable energy sources to transport fuels, however, large overpotentials and inability to control product selectivity are significant barriers to application. Recently, density functional theory (DFT) was used to evaluate the thermochemistry of CO2 electroreduction on various Cu surfaces, but questions about the preferred path remain. We report a systematic DFT study to evaluate the elementary kinetics (i.e. activation barriers) for CO2 electroreduction on the Cu(111) surface. The potential-dependent barriers incorporate the role of water through the explicit addition of 1 or 2 water molecules. We find that CO reduction to COH or CHO intermediate is the key selectivity step for production of methane/ethylene over methanol. Furthermore, the water faciliates a H-shuttling mechanism for O-H bond formation that can reduce the barriers and plays an important role in the preferred pathway. Our work provides a new path for CO2 electroreduction that matches recent electrokinetic experiments. We will also report on our current efforts to understand CO2 reduction on low-coordinated Cu structures, such as Cu(100) and Cu(211), along with our efforts to model the effect of additional water molecules on the kinetics of CO2 electroreduction on Cu surfaces.

DFT studies of kinetic barriers of CO<sub>2</sub> reduction on Cu electrodes

246th National Meeting (2013)

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DFT studies of kinetic barriers of CO2 reduction on Cu electrodes

DFT studies of kinetic barriers of CO₂ reduction on Cu electrodes