Atomic oxygen adsorption on Au (100) and bimetallic Au/M (M = Pt and Cu) surfaces

Periodic slab calculations in generalized gradient approximation density-functional theory (GGA-DFT) have been used to demonstrate how the existence of second metals can modify the atomic oxygen adsorption on Au (1 0 0) surfaces. The computed adsorption energies for atomic oxygen adsorbed at 0.125 ML (monolayer) surface coverage on the Au (1 0 0) and bimetallic Au-Pt (1 0 0), Au-Cu (1 0 0), Au-Pt-Au (1 0 0) and Au-Cu-Au (1 0 0) surfaces are 275.60, 417.96, 427.79, 283.38, and 275.55 kJ/mol, respectively. In all coverages, the adsorption energies E-ad(O) for Au-Pt and Au-Cu surfaces are higher than that for Au-Pt-Au, Au and Au-Cu-Au. In low coverage (0 < 0.5), the adsorption energy E-ad(O) for Au-Cu is larger than that for Au-Pt. As the coverage rises, E-ad(O) reduces and E-ad(O) for Au-Cu becomes smaller than that for Au-Pt. In Au-Cu-Au (1 0 0) surface, the largest shift in the d-band center away from the Fermi level results in the weakest oxygen binding energy. (C) 2012 Elsevier B.V. All rights reserved.