Methanol and methoxide decomposition on silver

作者：Montoya Alejandro^*; Haynes Brian S

来源：Journal of Physical Chemistry C, 2007, 111(27): 9867-9876.

DOI：10.1021/jp0711139

A periodic density functional modeling study of the partial oxidation of methanol to formaldehyde on an Ag(111) surface is presented. Methoxide binds strongly to the surface, preferentially to the highest coordination adsorption sites, while methanol and formaldehyde are weakly adsorbed far from the surface, with no preference for a particular site at low coverage. Energy paths for surface- and oxygen-assisted methanol O-H and methoxide C-H bond scission are compared for various pre-adsorbed oxygen species. Subsurface oxygen stabilizes the adsorbed phase by increasing the binding energy on Ag(111). The effect of subsurface oxygen as compared with the clean surface on the energy barrier of O-H and C-H bond scissions is less dramatic than the effect of onsurface oxygen. In the absence of onsurface oxygen, the O-H and C-H bond scission is hindered by a significant energy barrier, but in the presence of onsurface oxygen, these energy barriers are significantly reduced. Overall, the H transfer reaction in the presence of onsurface oxygen is exothermic from the adsorbed phase, while in the absence of onsurface oxygen, it is endothermic.

• 出版日期2007-7-12