Chemisorbed Oxygen at Pt(111): a DFT Study of Structural and Electronic Surface Properties

• Published in: Electrocatalysis 2018-05, Vol.9 (3), p.370-379
• Main Authors: Malek, Ali, Eikerling, Michael H.
• Format: Article
• Language: English
• Subjects: Adsorbates; Atomic oxygen; Catalysis; Charge density; Chemistry; Chemistry and Materials Science; Density functional theory; Dipole moments; Electrochemistry; Energy Systems; Original Research; Physical Chemistry; Surface properties; Water chemistry
• ISSN: 1868-2529; 1868-5994
• DOI: 10.1007/s12678-017-0436-0

Simulations based on density functional theory are used to study the electronic and electrostatic properties of a Pt(111) surface covered by a layer of chemisorbed atomic oxygen. The impact of the oxygen surface coverage and orientationally ordered interfacial water layers is explored. The oxygen adsorption energy decreases as a function of oxygen coverage due to the lateral adsorbate repulsion. The surficial dipole moment density induced by the layer of chemisorbed oxygen causes a positive shift of the work function. In simulations with interfacial water layers, ordering and orientation of water molecules strongly affect the work function. It is found that the surficial dipole moment density and charge density are roughly linearly dependent on the oxygen surface coverage. Moreover, we found that water layers exert only a small impact on the surface charging behavior of the surface. Graphical Abstract Plane-averaged line charge density at the Pt(111)–O ad surface in the presence of one monolayer of water.