Surface reactions of carbon dioxide at the adsorbed water-iron oxide interface.

Despite the fact that CO2 is an abundant atm. gas with profound environmental implications, there is little information on the reaction of CO2 at the adsorbed water-oxide interface. In this study, the chem. of CO2 at the adsorbed water-iron oxide interface was investigated with FTIR spectroscopy. As shown here, the thin water layer on the iron oxide surface plays an important role in the surface chem. of CO2. In particular, adsorbed water enhances CO2 uptake, undergoes isotope exchange with CO2 in O(18)-labeled expts., and influences the chem. nature of the predominant adsorbed product on the surface from bicarbonate to carbonate. The resultant thin water film is acidic in nature from the reaction of CO2. The IR spectrum recorded of adsorbed carbonate at the adsorbed water-iron oxide interface is remarkably similar to that at the bulk liq. water-iron oxide interface. Since reactions in thin water films estd. to be ≈2 layers will play a role in a no. of environmental processes, it is essential to understand the chem. of these "wet" interfaces with atm. gases. [on SciFinder(R)]