The orientation of acetate on a TiO2(110) surface

Abstract

The adsorption of acetic acid on a TiO2(110) surface has been studied using electron stimulated desorption ion angular distribution (ESDIAD) and low energy electron diffraction (LEED). The acetate intermediates arising from the dissociative adsorption of acetic acid form an ordered (2×1) overlayer at saturation coverage. The H+ ESD ion angular distributions can be resolved into two contributions: Those ions desorbing from hydrogen atoms bonded at the oxide substrate, and those ions desorbed via the rupture of the C–H bonds of the acetate. The geometry of the ESDIAD pattern led us to propose that the acetates are bridge bonded with the five-fold coordinated Ti 4+ ions, with their molecular plane perpendicular to the surface. Decomposition of acetate at room temperature occurs under electron beam irradiation, resulting in the desorption of CH2CO and CH3/CH4.