Sulphur overlayers on Ir(100) and its effect on the adsorption of CO: a DFT study
College of Physics and Information Engineering, Henan Normal
University, Xinxiang, Henan
a e-mail: email@example.com
Received in final form: 21 July 2011
Published online: 24 October 2011
Ordered sulphur overlayers adsorbed on Ir(100) surface are studied with different coverage ranging from 0.11 to 1.0 ML. Calculations indicate that atomic S adsorbs favourably in hollow sites, forming strong covalent bonds with the substrate surface and the adsorption energy is nearly unchanged at lower coverages (θS ≤ 0.50 ML). In good agreement with experimental observations, the p(2 × 2)-S and c(2 × 2)-S are predicted to be the most stable overlayers. The obtained surface electronic structure modifications induced by sulphur adsorption are coverage-dependent and the results are in accordance with the rectangular band and the Hammer-Nørskov models. Moreover, the effect of sulphur on the adsorption of CO is discussed in the p(2 × 2)-(S + CO) overlayer on Ir(100).
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2011