Application of temperature-programmed desorption to surfaces with physically adsorbed species

Abstract

Temperature-programmed desorption has been applied to physisorbed aliphatic alcohols and acids on a rutile pigment surface. Reproducible desorption chromatograms for a series of alcohol adsorbates indicate that the same sites are involved in adsorbing the series and that the adsorbate orientation from the surface deviates progressively from normal as the chain length increases. The data also infer a reduction in the activation energy of desorption with increasing chain length. Acid adsorbates also generate reproducible chromatograms, those for formic and acetic acid showing characteristic peaks near 300 °C. The reason for the very high stability of these adsorbates has not yet been resolved.