Imaging Adsorbate O−H Bond Cleavage: Methanol on TiO2(110)

Abstract
We investigated methanol adsorption and dissociation on bridge-bonded oxygen vacancies of the TiO2(110)-(1×1) surface using in situ scanning tunneling microscopy. We provide the first direct evidence that methanol dissociates on oxygen vacancies via O−H bond scission rather than C−O scission. For CH3OH coverages lower than the oxygen vacancy concentration, stationary methoxy−hydroxyl pairs form. At CH3OH coverages close to the oxygen vacancy concentration undissociated mobile CH3OH interacts with methoxy−hydroxyl pairs and facilitates the movement of hydroxyl away from the methoxy group.