Adsorption and diffusion of a single Pt atom on γ-Al2O3 surfaces

N. Aaron Deskins, Donghai Mei, Michel Dupuis

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Motivated to better understand the interactions between Pt and γ-Al2O3 support, the adsorption and diffusion of a single Pt atom on γ-Al2O3 was studied using density functional theory. Two different surface models with atoms of various coordination (3-5) were used, one derived from a defected spinel structure, and another derived from the dehydration of boehmite (AlOOH). Adsorption energies are similar for the two surfaces, about -2 eV for the most stable sites, and involve Pt binding to surface O atoms. An unusually strong trapping geometry whereby Pt moves into the surface was identified over the boehmite-derived surface. In all cases the surface transfers ∼0.2-0.3 e- to the Pt atom. The bonding is explained as being a combination of charge transfer between the surface and Pt atom, polarization of the metal atom, and some weak covalent bonding. The similarity of the two surfaces is attributed to the similar local environments of the surface atoms, as corroborated by geometry analysis, density of states, and Bader charge analysis. Calculated activation barriers (0.3-0.5 eV) for the defected spinel surface indicate fast diffusion and a kinetic Monte Carlo model incorporated these barriers to determine exact diffusion rates and behavior. The kinetic Monte Carlo results indicate that at low temperatures (

Original languageEnglish
Pages (from-to)2793-2807
Number of pages15
JournalSurface Science
Volume603
Issue number17
DOIs
Publication statusPublished - Sep 1 2009

Fingerprint

Adsorption
Atoms
adsorption
atoms
spinel
Kinetics
Geometry
kinetics
geometry
Dehydration
dehydration
Density functional theory
Charge transfer
Metals
Chemical activation
trapping
charge transfer
activation
Polarization
density functional theory

Keywords

  • Ab initio quantum chemical methods and calculations
  • Aluminum oxide
  • Atom-solid interactions
  • Monte Carlo simulations
  • Semiconducting surfaces

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Condensed Matter Physics
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Adsorption and diffusion of a single Pt atom on γ-Al2O3 surfaces. / Aaron Deskins, N.; Mei, Donghai; Dupuis, Michel.

In: Surface Science, Vol. 603, No. 17, 01.09.2009, p. 2793-2807.

Research output: Contribution to journalArticle

Aaron Deskins, N. ; Mei, Donghai ; Dupuis, Michel. / Adsorption and diffusion of a single Pt atom on γ-Al2O3 surfaces. In: Surface Science. 2009 ; Vol. 603, No. 17. pp. 2793-2807.
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