Does CO2dissociatively adsorb on Cu surfaces?

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Abstract
The interactions of CO2 with a clean Cu(110) surface have been studied both in an ultrahigh-vacuum surface analytical chamber and in an attached, high-pressure cell. No adsorption or dissociation of CO2 was measured for exposures up to 350 L at 110 K and 250 K. Exposures of 65 to 650 Torr of CO2 at 400-600 K led to the build-up of atomically adsorbed oxygen according to the reaction CO2.g to COg+Oa at a rate which increased with temperature ( approximately 16 kcal mol-1) and decreased with reaction time, saturating in a p(2*1)-O overlayer. The observed dissociative reaction probabilities for CO2 of approximately 10-9-10-11 (per collision with the surface) are favorably compared with predictions based upon the thermodynamics of adsorbed oxygen and the known kinetics of the reverse reaction: COg+Oa to CO2.g. The rates are also reasonably close to the reaction probability for CO2 reported in the reverse water-gas shift reaction over Cu-based catalysts, which suggests a catalytic redox mechanism involving the dissociative adsorption of CO2, followed by consumption of the resulting Oa by reaction with H2. The results also show that CO2:CO ratios in excess of approximately 100 would be required to produce significant oxygen concentrations on copper surfaces under catalytic methanol synthesis conditions. The authors were unable to produce surface carbonate from Oa plus CO2 on Cu(110).

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