Publication at Faculty of Mathematics and Physics |
2009
Abstract
The adsorption structure of phenylphosphonic acid (PPOA) on an alumina surface was investigated as a function of exposure and temperature using infrared reflected absorption spectroscopy (IRAS) and a Kelvin probe. At monolayer adsorption, P-O and Phenyl-P bands are observed, which indicate the creation of P-O-Al bonds.
The aromatic ring plane is positioned perpendicular to the surface. At multilayer adsorption, P=O and P-OH bands appear in the spectra.
The multilayer PPOA film starts to desorb at 400 K. From 400 to 700 K, the IRAS spectra are similar to the monolayer spectrum, indicating that the multilayer structure reverses to the monolayer-like PPOA adlayer by heating.
The acid molecules desorb at 700 K.