Carbon monoxide adsorption on iron in the temperature range 85 to 350 K as revealed by X-ray and vacuum ultraviolet [He(II)] photoelectron spectroscopy

Abstract

Vacuum ultraviolet [He(II)] and X-ray photoemission studies have provided information on the molecular state of adsorbed carbon monoxide on iron films. At 80 and 190 K adsorption is molecular but dissociation occurs slowly at 290 K and rapidly at 350 K. Preadsorption of hydrogen sulphide and studies of the displacement of adsorbed carbon monoxide by hydrogen sulphide provide further evidence for the nature and mechanism of bonding. The conclusions are consistent with the recent suggestion that 250 kJ mol–1 is the threshold heat of adsorption on metals above which dissociation of carbon monoxide occurs at 290 K.The present results provide the basis of a self-consistent interpretation of published data obtained by a variety of techniques of the Fe + CO system.