Characterization of CO2 Adsorption and Reaction on Single Crystal Metal Surfaces

The adsorption and activation of carbon dioxide on metal surfaces is an important elementary step in many catalytic reactions such as the alcohol synthesis reaction1,2 or the water-gas shift reaction3. In catalysis, environmental and surface science, carbon dioxide has been of interest as a reaction product resulting from the oxidation of CO 4 or from the CO disproportionation (Boudart) reaction 2CO - C + CO2. In surface science the adsorption of CO2 is also an interesting generic problem, if only for the reason that the study of CO2 adsorption properties seem to be a logical extension after countless papers/studies on the adsorption properties of carbon monoxide. In contrast to carbon monoxide, however, carbon dioxide adsorbs only weakly on most metal surfaces with few exceptions 6,7. In order to react, the molecule must be activated. On metal surfaces this can be achieved either at high pressure or by modifying the surface with oxygen 8 or alkali metals 9-18. The latter case is of particular importance due to the use of alkali promoters in catalytic reactions, e.g. in alcohol synthesis.