PNNL

Abstract

The adsorption and reaction of methanol (CH3OH) on stoichiometric (TiO2-terminated) and reduced SrTiO3(100) surfaces have been investigated using temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and first-principles density-functional calculations. Methanol adsorbs mostly nondissociatively on the stoichiometric SrTiO3(100) surface that contains predominately Ti4+ cations. Molecular desorption of methanol from the stoichiometric surface is observed at ~250 K whereas the multilayer is found to desorb at ~160 K. Theoretical calculations predict weak adsorption of methanol on TiO2–terminated SrTiO3(100) surfaces, in agreement with the experimental results. However, the reduced SrTiO3(100) surface containing substantial amounts of Ti3+ cations exhibits higher reactivity towards adsorbed methanol and H2, C2H4, and CO are the major decomposition products observed on the reduced surface. The surface defects on the reduced SrTiO3(100) surface are partially reoxidized upon saturation exposure of CH3OH onto this surface at 300 K.