Paper EN+SS-FrM6
A Theoretical Study of Carbon Dioxide Reduction on Catalysts

Friday, November 2, 2012, 10:00 am, Room 15

Catalytic reduction of carbon dioxide into fuels would provide an ideal storage medium for intermittent renewable energy sources. Copper and copper oxides electro-catalysts have been found to be capable of producing significant quantities of hydrocarbons or alcohols from CO₂ in aqueous solutions. Selectivity to methanol is speculated to be due to Cu(I) species in electrochemical systems; however, these pathways have not been experimentally verified. Here, the third-generation charge optimized many body (COMB3) potentials, which are proven to be successful to characterize different types of bonding in the heterogeneous systems, are employed to investigate the atomic scale mechanisms associated with catalytic reactions on Cu surfaces and clusters supported on metal oxide surfaces. In particular, the reaction free energies of selected CHO molecules on the Cu (211) surface are investigated and validated with density functional theory calculations. The electrochemical systems are simulated with room temperature, low-energy (5 or 10 eV) deposition of CO₂ or CO₂+H₂O on the Cu (211) surface and Cu cluster interface with the ZnO (101-1) surface. The results suggest that the higher incident energy and the presence of water molecules facilitate CO₂ dissociation. The charge state of the Cu cluster and the charge transfer process are predicted to play significant roles in the selectivity of the catalysts. In particular, the Cu(I) species at the Cu/ZnO interface are predicted to be preferable sites for CO₂ reduction and dissociation, which is consistent with experimental observations. This work was supported as part of the Center for Atomic Level Catalyst Design, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under award number DE-SC0001058.