Oxidation of Small Silver Clusters: A Density Functional Theory Study
Journal article, 2010

The oxidation of small silver clusters (Ag-n, n <= 9) was investigated through electronic structure calculations based on density functional theory. The adsorption energies of molecular and dissociated adsorption show a pronounced odd/even alternation, with lower energies calculated for even-sized clusters. Molecular adsorption is favored for n <= 5, whereas dissociation is preferred for the larger sizes. Molecular oxygen is adsorbed in atop (Ag, Ag-2, Ag-6, Ag-8) or bridge (Ag-3, Ag-4, Ag-5, Ag-7, Ag-9) configurations, and atomic oxygen is preferably adsorbed in 3-fold hollow positions. Results for stoichiometric (Ag2nOn) clusters were compared to O-2 adsorption on Ag(111), and ab initio thermodynamics was used to estimate the temperature for the oxide-to-metal phase transition. The barrier for O-2 dissociation on Ag-8 was calculated to be higher than the corresponding barrier on Ag(111), which indicates a slower oxidation process. Adsorption of NOx onto the oxidized clusters was found to proceed through a formal reduction of the clusters; that is, NOx is adsorbed as NOx+1 with x = 1, 2.

simple-models

transition-metal clusters

surface

nox

molecular-oxygen

ag

hydrogen

adsorption

chemisorption

binding-energy

Author

Simon Klacar

Competence Centre for Catalysis (KCK)

Chalmers, Applied Physics, Chemical Physics

Anders Hellman

Chalmers, Applied Physics, Chemical Physics

Competence Centre for Catalysis (KCK)

Itai Panas

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Henrik Grönbeck

Competence Centre for Catalysis (KCK)

Chalmers, Applied Physics, Chemical Physics

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 114 29 12610-12617

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Energy

Materials Science

Roots

Basic sciences

Subject Categories

Atom and Molecular Physics and Optics

Chemical Sciences

DOI

10.1021/jp102715r

More information

Created

10/7/2017