Interactions in bimetallic bonding. Electronic and chemical properties of PdZn surfaces

Journal Article · Thu Jun 02 00:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100073a031· OSTI ID:7182914

Rodriguez, J A ^[1]

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1. Brookhaven National Lab., Upton, NY (United States)

The properties of PdZn surfaces have been examined using thermal desorption mass spectroscopy, core- and valence-level photoemission, and CO chemisorption. The formation of Pd-Zn bonds increases the binding energy of the core and valence levels of Pd and reduces the binding energy of the core and valence levels of Zn. An equiatomic PdZn alloy exhibits a large depletion of Pd(4d) states near the Fermi level and a shift of [approximately] +0.7 eV in the binding energy of the Pd(3d) levels. Ab initio SCF calculations for the PdZn molecule and Pd[sub n]Zn[sub n] (n = 2-4) clusters show a decrease in the electron population of the Pd(4d) orbitals as a consequence of Pd(4d) [yields] Zn(4p) charge transfer and Pd(4d) [yields] Pd(5s,5p) rehybridization. These electron transfers reduce electron-electron repulsion within a Pd atom, shifting its core and valence levels toward higher binding energy. The electronic perturbations induced by Zn on Pd reduce the CO-chemisorption ability of Pd by weakening the Pd(4d)-CO(2[pi]) bonding interactions. PdZn surfaces that are rich in Zn show Pd-CO bonds that are 12-16 kcal/mol weaker than those seen on pure Pd surfaces. 57 refs., 12 figs., 1 tab.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7182914
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:22; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201 -- Chemical & Physicochemical Properties
ALLOYS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CHALCOGENIDES
CHARGE TRANSPORT
CHEMICAL BONDS
CHEMICAL REACTIONS
CHEMISORPTION
COHERENT SCATTERING
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON SPECTROSCOPY
ELECTRON TRANSFER
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY LEVELS
FERMI LEVEL
MASS SPECTROSCOPY
METALS
OXIDES
OXYGEN COMPOUNDS
PALLADIUM ALLOYS
PHOTOELECTRON SPECTROSCOPY
PLATINUM METAL ALLOYS
PLATINUM METALS
RUTHENIUM
SCATTERING
SEPARATION PROCESSES
SOLID CLUSTERS
SORPTION
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENTS
ULTRAHIGH VACUUM
X-RAY SPECTROSCOPY
ZINC ALLOYS