Surface segregation in a polycrystalline Pd70Cu30 alloy hydrogen purification membrane

Journal Article · Mon Dec 31 23:00:00 EST 2007 · Surface Science

DOI:https://doi.org/10.1016/j.susc.2007.10.031· OSTI ID:925842

Miller, J B; Matranga, C; Gellman, A J

X-ray photoelectron spectroscopy (XPS) and low energy ion scattering spectroscopy (LEISS) have been used to study the effects of various surface preparations and thermal treatments on the composition of the near-surface region (~7 atomic layers) and the topmost atomic layer of a polycrystalline Pd70Cu30 alloy. Palladium enrichment (relative to the bulk composition) is observed in the XPS-accessible near-surface region, but copper enrichment is observed in the topmost atomic layer. At temperatures above ~800 K, where the bulk, the near-surface region and the topmost atomic layer are likely in thermodynamic equilibrium, segregation to the top layer can be described in terms of a simple thermodynamic model. Temperature programmed desorption (TPD) of H2 and CO from the annealed surfaces illustrates the impact of segregation and atomic distribution in the top layer on surface chemical activity.

• Research Organization: National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
• Sponsoring Organization: USDOE - Office of Fossil Energy (FE)
• OSTI ID: 925842
• Report Number(s): DOE/NETL-IR-2008-067
• Journal Information: Surface Science, Journal Name: Surface Science Journal Issue: 1 Vol. 602; ISSN 0039-6028
• Publisher: Elsevier B.V.
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
ADSORPTION HEAT
ALLOYS
CHEMISORPTION
COPPER
DESORPTION
HYDROGEN
Low energy ion scattering (LEIS)
MEMBRANES
MORPHOLOGY
PALLADIUM
PENTACENE
PURIFICATION
PdCu alloy
SCATTERING
SEGREGATION
SILICON
SORPTIVE PROPERTIES
SPECTROSCOPY
Separation membrane
Surface segregation
THERMODYNAMIC ACTIVITY
THERMODYNAMIC MODEL
THERMODYNAMICS
X-RAY PHOTOELECTRON SPECTROSCOPY
X-ray photoelectron spectroscopy (XPS)