INTERACTION OF CARBON-DIOXIDE WITH POTASSIUM-PROMOTED FE(110) .1. DEPENDENCE ON POTASSIUM COVERAGE AND CARBON-DIOXIDE EXPOSURE AT 85-K

Adsorption of carbon dioxide on potassium-covered Fe(110) at 85 K has been studied by means of UV photoelectron spectroscopy (UPS), X-ray ph otoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and change in work function (Delta Phi). Only a small amount of carbon dio xide dissociates into carbon monoxide and oxygen. The main reaction oc curring in the studied coverage range up to one monolayer of potassium is the formation of a carbonate species and carbon monoxide. After sa turation with carbonate, linear carbon dioxide is adsorbed. For potass ium coverages exceeding half a monolayer, a further species could be d etected with UPS. Its chemical nature is discussed and a model of the reaction paths in the investigated system is developed.