Formation of surface adspecies at furan and tetrahydrofuran adsorption on the Pt surface studied by work function changes and Auger electron spectroscopy

The adsorption of tetrahydrofuran (THF) and furan (F) on polycrystalline Pt-foil has been studied by work function change (A phi) measurements and Auger electron spectroscopy (AES). The results were compared with those obtained earlier for the adsorption of cyclic hydrocarbons. The general character of the adsorption process (i.e. the dependence of vertical bar Delta phi vertical bar and C/Pt ratio on temperature and exposure, and the vertical bar Delta phi vertical bar vs. C/Pt correlation) is similar to the one observed during adsorption of cyclic hydrocarbons. THF produces sigma-bonded adspecies in a similar manner to cyclopentane. F forms first a pi-bonded surface complex, as do benzene and toluene. The pi-adsorbed species are then transformed into sigma-bonded ones under exposure to excess F. The numeric values characterizing the adsorption of the two heterocycles (mainly the C/Pt values) differ substantially from those measured for the adsorption of cyclic hydrocarbons. (c) 2007 Elsevier B.V. All rights reserved.