Adsorption of methanol, formaldehyde and ammonia on W(100) studied by ultra-violet photoelectron spectroscopy

Abstract

The adsorption of methanol, formaldehyde and ammonia on W(100) at room temperature has been studied by ultra-violet photoelectron spectroscopy. It is shown how UPS may be used as a fingerprint technique to monitor the chemical nature of the ad-layer during the progress of a decomposition reaction on the surface. Both methanol and formaldehyde, at saturation coverages, adsorb as molecular complexes with spectra which are dependent upon the coverage of the tightly bound β-CO layer formed during the early stages of the adsorption. The photoelectron spectra of these complexes of methanol and formaldehyde, and also of ammonia, adsorbed on surfaces of different composition are discussed in relation to the gas phase spectra and the available free valence of the substrate.