Adsorption and decomposition of CO on stepped Fe(310) surfaces

First-principle DFT calculations for the chemisorption and reaction of CO on the stepped Fe(310) surface were performed. It is found that among the many possible adsorption sites CO is bound preferably to the hollow sites of the (100) terraces in a tilted geometry analogous to the adsorption of CO on the regular Fe(100) surface. The computed binding energy of 42.7 kcal/mol is similar to that for the CO adsorption on a more organized Fe(100) surface. An intriguing positive correlation of the CO adsorption energy with the surface coverage is noticed; the CO binding energy is increased to 44.2 kcal/mol when the surface coverage reaches 0.500 ML. Two CO decomposition pathways on Fe(310) have been explored. These processes do not show any significant contributions to the overall rate of CO dissociation at 0.250 ML because of their low exothermicity. Nevertheless, they become very prominent at 0.500 ML; it is estimated that the presence of 30% (by surface units) Fe(310) steps on the Fe(100) surface causes a 20% increase in the decomposition of adsorbed CO at 473 K.