Adsorption of carbon dioxide on Cu(110) and on hydrogen and oxygen covered Cu(110) surfaces

The interaction of CO2 with a clean Cu(110) surface and with pre-adsorbed oxygen and hydrogen on this surface has been studied in ultra-high vacuum at temperatures between 20 and 500 K with temperature programmed thermal desorption, low-energy electron diffraction, Auger electron spectroscopy, high-resolution electron energy loss spectroscopy and work function change measurements. CO2 adsorbs only molecularly on the clean and on the hydrogen(1x2) and oxygen(2x1) reconstructed Cu(110) surface, respectively. The initial sticking probability of CO2 is not affected by co-adsorption of oxygen or hydrogen, although the CO2 adsorption is energetically stabilised in this case by 1.3 and 5.4 kJ mol(-1), respectively. On clean Cu(110), the isosteric heat of adsorption rises with coverage from similar to 13 to 25 kJ mol(-1) at saturation. High-resolution electron energy loss spectroscopy suggests that the isolated carbon dioxide molecule is adsorbed in a linear configuration on the clean and on the reconstructed surfaces, while for coverages > 0.1 three-dimensional clustering occurs. Our experiments reveal that neither dissociation into oxygen and carbon monoxide nor hydrogenation of carbon dioxide occurs under the experimental conditions.