Effect of Pd and Pt metal on sulfur adsorption on Co(0001) by surface alloying

Using first-principles calculation, we have studied the properties of a series of M<Subscript> x </Subscript>Co<Subscript>1−x </Subscript>/Co(0001) (M=Pd, Pt) bimetallic surface alloys with atom M ratios from 0.25 to 1.0, then the effect of alloyed M metal on the properties of S adsorbed on these surfaces are discussed. Our calculations show that the alloying of metal Pd, Pt on Co(0001) weakens the S-M (M=Pd, Pt, Co) bond strength compared to monometallic surfaces and the site preference of sulfur atom is dependent on the alloyed metal M and its surface concentration. Moreover, bimetallic surface electronic structure modifications with and without sulfur are analyzed in comparison with clean Co(0001), and the correlation between the sulfur adsorption energy and the bimetallic surface d-band center is presented. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2014