Chemisorption bond energies of Lewis acids and bases on oxygen modified Mo(100) surfaces

Abstract

The acid-base properties of three molybdenum (100) surfaces chemically modified by 1.5, 1.2, and 1.0 monolayers (ML) of atomic oxygen were investigated by thermal desorption spectroscopy using a series of molecular Lewis bases. The molecules used in this study were of three types, hard Lewis bases, ammonia and dimethylether, soft Lewis bases, phosphine, ethene and propene, and two π acids, carbon monoxide and 3,3,3-trifluoropropene. The trends in desorption energies are consistent with the expectation that the molecules would adsorb at localized, acidic surface sites. The desorption energies are correlated with proton affinities, and the 1.5 ML oxygen modified surface was found to most resemble a gas phase proton.