Methanol Decomposition on Cu(111): A DFT Study

Self-consistent periodic DFT–GGA calculations are used to investigate the methanol decomposition pathway on both equilibrium and stretched Cu(111) surfaces. The thermochemistry and kinetics of the decomposition via sequential hydrogen abstraction are both found to be highly unfavorable. The second step in this pathway, the abstraction of hydrogen from the methoxy intermediate, has large thermochemical (∼0.6 eV) and kinetic (∼1.4 eV) barriers. Our thermochemical results indicate that methanol, formaldehyde, and carbon monoxide are weakly bound to the surface and will likely desorb before undergoing any reaction under UHV conditions. In contrast, methoxy, formyl, and atomic hydrogen are much more strongly bound. Introduction of a 4% lateral strain to the Cu(111) lattice decreased the transition state energy of the methoxy hydrogen abstraction step, suggesting that strain might facilitate the kinetics of this reaction.