Ultraviolet photoemission and flash-desorption studies of the chemisorption and decomposition of methanol on Ni(111)

The chemisorption and decomposition of methanol (CH3OH) on Ni(111) has been studied by ultraviolet photoemission spectroscopy (UPS) and flash-deposition mass spectroscopy. The UPS spectra suggest that exposure at ∠80 K produces chemisorbed CH3OH in which the chemisorption interaction affects two molecular orbitals, the oxygen lone-pair oriented perpendicular to the COH plane and an in-plane orbital having mixed lone-pair and σ-bonding character. Upon warming to ∠160 K, some CH3OH desorption occurs and the UPS spectrum changes markedly. Further warming to ∠300 K produces H2 desorption and leaves chemisorbed CO as the final decomposition product on the surface.