Lateral interaction effects on the reaction of CO2 and oxygen adsorbed on Ag(110)

Abstract

The effect of oxygen adatom coverage and order upon the formation of CO3 intermediates via CO2+O(a)→CO3(a) was examined on the Ag(110) surface. The reaction probability for CO2 was found to be strongly dependent upon the oxygen adlayer. Adsorption of CO2 upon an ordered oxygen adlayer at 300 K occurred with a net reaction probability of the order of 10−2 or less, and resulted in the formation of (1×2) domains of CO3 which caused compression of the adsorbed (n×1) oxygen atom chains as determined by LEED experiments. Adsorption of CO2 upon a disordered oxygen adlayer at 170 K occurred with an initial sticking probability of unity; however, the saturation coverage of CO3 intermediates formed was less than the initial oxygen atom coverage. Adsorption of CO2 upon an ordered oxygen adlayer at 170 K occurred with lower reaction probability than at 300 K, indicating that the order of the oxygen adlayer strongly affected the CO2 reaction kinetics. In all cases the reaction of CO2 was hindered by increasing the initial oxygen atom coverage.