The interfaces between water and pure Pt(111) surfaces, with and without melamine, and monolayer Pt skins on Pt alloy (111) surfaces are modeled as shown in Fig. . The solid surfaces were approximately modeled using electrically neutral 4-layer slabs with a 3×2 √ 3 periodicity. For Pt alloys, we evaluated the near-surface alloys Pt/Pt 1-x Cu x /Pt(111) (x=1/3, 2/3, and 1). In a previous experimental and theoretical study, 55 these near-surface alloy single crystals with well-controlled structure and composition were synthesized by annealing Pt(111) surfaces with Cu adsorbates deposited by underpotential deposition, and the redox potentials forming OH* and the ORR rate on these surfaces were experimentally identified.