INTERACTION OF WATER WITH POTASSIUM ON GRAPHITE - A HREELS STUDY

Water and coadsorbed water + potassium on the basal plane of graphite were studied with high resolution electron energy loss spectroscopy (H REELS) at 85 K and after stepwise annealing up to 500 K. Water adsorbs non-dissociatively on both clean and potassium precovered surface at 85 K. The vibration spectra, together with thermal desorption spectros copy (TDS) reveal a series of reactions within the coadsorbed layer le ading to the formation of KOH, KH, and KOx and volatile products. Even tually a precursor to CO2 formation, of yet unindentified composition and observed also in K + O-2 coadsorption studies on graphite, is obse rved at approximate to 27 meV.