Since it is often used as a measure of the adsorption energy and therefore also of the chemical reactivity of catalyst surfaces, based on the d-band model and on the Sabatier principle, we evaluated the local density of states (LDOS) on the Pt atoms in the topmost layer for the three surface alloys with Pt1, Pt2, and Pt3 ensembles in the surface layer (Pt = 1 /9, 2 /9, 3 /9 ), respectively, on the pure Pt4L slab, and with one or two Ag sublayers in between. Figure shows the local DOS of the d-states projected on the Pt surface atoms in the pure Pt(111) surface and in the three corresponding surface alloys. Since this was discussed already in detail earlier, we here only summarize the main findings.