Chemisorption and diffusion of atomic hydrogen in and on cluster models of Pd, Rh, and bimetallic PdSn, RhSn, and RhZn catalysts

Journal Article · Tue Nov 06 23:00:00 EST 1990 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00179a003· OSTI ID:5757660

Rochefort, A; Andzelm, J; Salahub, D R ^[1]; Russo, N ^[2]

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1. Univ. de Montreal, Quebec (Canada)
2. Univ. della Calabria, Cosenza (Italy)

Results of LCGTO-MCP-LSD (Linear Combination of Gaussian Type Orbitals-Model Core Potential-Local Spin Density) calculations are reported for chemisorption and for bulk and surface diffusion of atomic hydrogen on clusters simulating the (111) and (100) surfaces of pure transition metals (Pd and Rh) and bimetallic catalysts (PdSn, RhSn, and RhZn). The replacement of a Pd or Rh atom near the hydrogen atom by Sn decreases the binding energy for hydrogen adsorption. In particular, the decrease is most pronounced when the non-transition metal lies in the first surface layer (e.g. 3.8 eV (2.4 eV) for Pd (PdSn) and 4.1 eV (2.8 eV) for Rh (RhSn)) but is also significant when the non-transition metal is placed as a second neighbor (e.g. 3.8 eV (3.1 eV) for Pd(PdSn) and 4.1 eV (2.9 eV) for Rh(RhSn)). For Zn substitution the behavior is less regular, one case of an increase in binding energy has been found. The presence of Sn or Zn on the surface significantly increases the equilibrium bond distances (e.g. 1.76 {angstrom} for Pd{sub 3}Pd vs 1.93 {angstrom} for Pd{sub 2}SnPd) and decreases the hydrogen perpendicular vibrational frequencies (e.g. 1166 cm{sup {minus}1} for Pd{sub 3}Pd vs 988 cm{sup {minus}1} for Pd{sub 2}SnPd).

• OSTI ID: 5757660
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 112:23; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALLOYS
BINDING ENERGY
CATALYSTS
CHEMICAL REACTIONS
CHEMISORPTION
DIFFUSION
ELEMENTS
ENERGY
ENERGY LEVELS
FUNCTIONS
HYDROGEN
MATHEMATICAL MODELS
METALS
MILLER INDICES
NONMETALS
PALLADIUM
PERMEABILITY
PLATINUM METALS
RHODIUM
SEPARATION PROCESSES
SOLID CLUSTERS
SORPTION
TIN ALLOYS
TRANSITION ELEMENTS
WAVE FUNCTIONS