Oxidation of Small Silver Clusters: A Density Functional Theory Study
Artikel i vetenskaplig tidskrift, 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

Författare

Simon Klacar

Kompetenscentrum katalys (KCK)

Chalmers, Teknisk fysik, Kemisk fysik

Anders Hellman

Chalmers, Teknisk fysik, Kemisk fysik

Kompetenscentrum katalys (KCK)

Itai Panas

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Henrik Grönbeck

Kompetenscentrum katalys (KCK)

Chalmers, Teknisk fysik, Kemisk fysik

Journal of Physical Chemistry C

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

Vol. 114 29 12610-12617

Styrkeområden

Nanovetenskap och nanoteknik

Energi

Materialvetenskap

Fundament

Grundläggande vetenskaper

Ämneskategorier

Atom- och molekylfysik och optik

Kemi

DOI

10.1021/jp102715r

Mer information

Skapat

2017-10-07