Unified picture of the molecular adsorption process: O2/Pt(111)
نویسندگان
چکیده
Tight-binding molecular dynamics simulations of the adsorption of O2/Pt(111) have been performed based on an ab initio potential energy surface. We demonstrate that, contrary to common belief, in this system the whole adsorption probability as a function of the kinetic energy can be understood in terms of trapping into chemisorbed molecular precursor states. This provides a novel unified picture of the trapping process which is relevant for the general understanding of adsorption. Furthermore, by simple steric arguments we are able to explain why O2 does not dissociate on cold Pt(111) surfaces even at kinetic energies that are much greater than the dissociation barrier.
منابع مشابه
A DFT Study on the O2 Adsorption Properties of Supported PtNi Clusters
We present a systematic study on the adsorption properties of molecular oxygen on Pt, Ni and PtNi clusters previously deposited on MgO(100) by means of density functional theory calculations. We map the different adsorption sites for a variety of cluster geometries, including icosahedra, decahedra, truncated octahedra and cuboctahedra, in the size range between 25–58 atoms. The average adsorpti...
متن کاملInteractive Surface Chemistry of CO2 and NO2 on Metal Oxide Surfaces: Competition for Catalytic Adsorption Sites and Reactivity
Interactive surface chemistry of CO2 and NO2 on BaOx/Pt(111) model catalyst surfaces were investigated via X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) techniques with a particular emphasis on the competition between different adsorbates for the catalytic adsorption sites and adsorbateinduced morphological changes. After NO2 adsorption, nitrated BaOx/Pt(111...
متن کاملAb initio molecular dynamics simulations of the O2/Pt(111) interaction
The interaction of molecular oxygen with Pt(111) has been studied using ab initio molecular dynamics simulations based on periodic density functional theory (DFT) calculations. The adsorption probability has been determined as a function of the initial kinetic energy and the surface temperature. In addition, the effect of coupling the substrate to a thermostat has been studied. In agreement wit...
متن کاملNear neutrality of an oxygen molecule adsorbed on a Pt(111) surface.
The charge state of paramagnetic or nonmagnetic O2 adsorbed on a Pt(111) surface is analyzed using density functional theory. We find no significant charge transfer between Pt and the two adsorbed molecular precursors, suggesting these oxygen reduction reaction (ORR) intermediates are nearly neutral, and changes in magnetic moment come from self adjustment of O2 spin-orbital occupations. Our fi...
متن کاملInfluence of water on elementary reaction steps in electrocatalysis.
We studied simple reaction pathways of molecules interacting with Pt(111) in the presence of water and ions using density functional theory within the generalized gradient approximation. We particularly focus on the dissociation of H2 and O2 on Pt(111) which represent important reaction steps in the hydrogen evolution/ oxidation reaction and the oxygen reduction reaction, respectively. Because ...
متن کامل