The adsorption and dissociation of multilayer CHOH on TiO（110）

The adsorption and dissociation of CH3OH on TiO2(110) were studied using density functional theory methods. Our results suggest that CH3OH molecules can adsorb up to 3/4 ML(1 ML=5.2×1014 molecules/cm2) coverage at five-coordinated titanium(Ti5c) sites to form the first layer. In the second layer, the CH3OH is adsorbed at bridge-bonded oxygen, and from the third layer, the CH3OH molecules form a hydrogen-bonded network with each other. The theoretical results show that dissociation of multilayer adsorbed methanol to aldehyde occurs through a stepwise pathway, with easy O–H bond dissociation and rate-determining C–H bond dissociation. The dissociation barriers for 8 or 12 CH3OH molecules on TiO2 are higher than that for low coverage by 0.15–0.21 e V; this suggests that the dissociation of multilayer adsorbed CH3OH is harder.