INTERACTION OF CO WITH CARBON AND CARBON SURFACE OXIDES

The surface complexes formed when Spherocarb is exposed to CO have been investigated over a wide range of temperatures (420-970 K) and CO pressures (0.2-8.0 kPa) using thermogravimetry and a mass-spectral analysis of evolved gases. Relative to oxygen, carbon monoxide has only a limited propensity to chemisorb to a carbon surface and the nature of the complexes formed in the two systems is also different, as evidenced by their distinct TPD patterns. The CO/carbon reaction is a poor model for the reverse of surface oxide decomposition in the O2/carbon system where CO formation apparently arises from irreversible processes, perhaps involving concerted rearrangements of the carbon substrate. There is very little interaction between gaseous CO and surface oxides in the range of temperature and CO partial pressures investigated. The production of CO2 during TPD of surface complexes, whether derived from CO or from O2, is a primary process, not involving CO.