Skip to content.

TUD

search  |  internal  |  deutsch
Personal tools
TU Dresden » Faculty of Mechanical Science and Engineering » Institute for Materials Science » Chair of Materials Science and Nanotechnology


prev/next pubs | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998 | 1997 | 1996

[back]


106. 


Ab initio study of element segregation and oxygen adsorption on PtPd and CoCr binary alloy surfaces



A. Dianat, J. Zimmermann, N. Seriani, M. Bobeth, W. Pompe, L. Colombi Ciacchi

Surface Science 602, 876 (2008)

The segregation behavior of the bimetallic alloys PtPd and CoCr in the case of bare surfaces and in the presence of an oxygen ad-layer has been studied by means of first-principles modeling based on density-functional theory (DFT). For both systems, change of the d-band filling due to charge transfer between the alloy components, resulting in a shift of the d-band center of surface atoms compared to the pure components, drives the surface segregation and governs the chemical reactivity of the bimetals. In contrast to previous findings but consistent with analogous PtNi alloy systems, enrichment of Pt atoms in the surface layer and of Pd atoms in the first subsurface layer has been found in Pt-rich PtPd alloy models, despite the lower surface energy of pure Pd compared to pure Pt. Similarly, Co surface and Cr subsurface segregation occurs in Co-rich CoCr alloys. However, in the presence of adsorbed oxygen, Pd and Cr occupy preferentially surface sites due to their lower electronegativity and thus stronger oxygen affinity compared to Pt and Co, respectively. In either cases, the calculated oxygen adsorption energies on the alloy surfaces are larger than on the pure components when the more noble components are present in the subsurface layers.



doi absolute link10.1016/j.susc.2007.12.016
publisher site (ISSN:0039-6028)
online abstractarXiv preprint: 0807.2787
CiteBaseCiteBase
export BibTeX citation (txt file)
export EndNote citation (ris file)


prev/next 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998 | 1997 | 1996

[back]



















































last modified: 2017.02.20 Mo
author: webadmin

contact
Prof. Dr. Gianaurelio Cuniberti
secretariat:
Ms Sylvi Katzarow
phone: +49 (0)351 463-31420
fax: +49 (0)351 463-31422
office@nano.tu-dresden.de
postal address:
Institute for Materials Science
TU Dresden
01062 Dresden, Germany
visitors and courier address:
HAL building
TU Dresden
Hallwachsstr. 3
01069 Dresden, Germany
Max Bergmann Center
TU Dresden
Budapester Str. 27
01069 Dresden, Germany