Charging effects on bonding and catalyzed oxidation of CO on Au8 clusters on MgO.
Gold octamers (Au8) bound to oxygen-vacancy F-center defects on Mg(001) are the smallest clusters to catalyze the low-temperature oxidation of CO to CO2, whereas clusters deposited on close-to-perfect magnesia surfaces remain chemically inert. Charging of the supported clusters plays a key role in promoting their chemical activity. Infrared measurements of the stretch vibration of CO adsorbed on mass-selected gold octamers soft-landed on MgO(001) with coadsorbed O2 show a red shift on an F-center-rich surface with respect to the perfect surface. The experiments agree with quantum ab initio calculations that predict that a red shift of the C-O vibration should arise via electron back-donation to the CO antibonding orbital.
Yoon
Bokwon
B
School of Physics, Georgia Institute of Technology, Atlanta, GA 30332-0430, USA.
Häkkinen
Hannu
H
Landman
Uzi
U
Wörz
Anke S
AS
Antonietti
Jean-Marie
JM
Abbet
Stéphane
S
Judai
Ken
K
Heiz
Ueli
U