Reduction behavior of oxidized Pd(100) and Pd75Ag25(100) surfaces using CO

The reduction of the (A root 5x root 5)R27 degrees surface oxide on Pd(100) and Pd75Ag25(100) surfaces by CO has been investigated by high-resolution X-ray photoelectron spectroscopy in combination with kinetic analysis using the Avrami-Erofeev theory. For both surfaces we observed faster reduction with increasing temperature. Kinetic analysis indicates that the reduction process is phase boundary controlled for Pd(100) in the temperature range investigated, from 30 degrees C to 120 degrees C On Pd75Ag25(100) the surface oxide reduction is significantly slower compared to Pd(100). Also in this case, a phase boundary controlled reduction of the surface oxide is observed at temperatures of 120 C and above, while at T <= 70 degrees C the reduction is found to be diffusion limited. Density functional theory calculations show that the presence of silver in the outermost surface layer significantly increases the CO diffusion barriers on the reduced areas, supporting a diffusion limited reduction process for Pd75Ag25(100) at lower temperatures. (C) 2013 Elsevier B.V. All rights reserved.

NATURVETENSKAP Fysik Atom- och molekylfysik och optik hsv//swe
NATURAL SCIENCES Physical Sciences Atom and Molecular Physics and Optics hsv//eng
Surface oxide reduction
Pd75Ag25(100)
Pd(100)
Photoelectron
spectroscopy
Avrami kinetics
Density functional theory

Gustafson, JohanLund University,Lunds universitet,Synkrotronljusfysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Synchrotron Radiation Research,Department of Physics,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)slju-jgu (författare)
Svenum, I. -H. (författare)
Farstad, M. H. (författare)
Walle, L. E. (författare)
Blomberg, SaraLund University,Lunds universitet,Synkrotronljusfysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Synchrotron Radiation Research,Department of Physics,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)slju-sbl (författare)
Lundgren, EdvinLund University,Lunds universitet,Synkrotronljusfysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Synchrotron Radiation Research,Department of Physics,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)slju-elu (författare)
Borg, A. (författare)
SynkrotronljusfysikFysiska institutionen (creator_code:org_t)

Av författaren/redakt...: Fernandes, V. R.; Gustafson, Johan; Svenum, I. -H.; Farstad, M. H.; Walle, L. E.; Blomberg, Sara; visa fler...; Lundgren, Edvin; Borg, A.; visa färre...

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