Effects of chemisorption on the surface composition of bimetallic catalysts

Journal Article · Tue Apr 15 04:00:00 EDT 1997 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1997.1587· OSTI ID:563479

Zhu, Ling; Wang, Ruoping ^[1]; King, T S ^[2]

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1. Ames Lab., IA (United States)
2. Iowa State Univ., Ames, IA (United States); and others

The authors have investigated the effect of hydrogen chemisorption on the surface composition of bimetallic RhPt catalytic clusters using the bond order metal simulation model. The differences in adsorption energies of hydrogen on Rh and on Pt for one monolayer of hydrogen are obtained by scaling the values for single-hydrogen adsorption, predicted by non-self-consistent electron density functional theory, until the results for surface segregation data from nuclear magnetic resonance are reproduced. The authors find the best fit with energy differences of -8.19 and -12.75 kJ/mol for three- and fourfold fcc hollow sites, respectively, in excellent agreement with the recent calorimetric measurements of -6 kJ/mol for the average heat of adsorption. In the presence of hydrogen, these cluster surfaces are Rh-rich, especially for the fcc(100) faces, completely reversing the segregation of Pt to the surface of the bare cluster. 23 refs., 2 figs., 1 tab.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 563479
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 167; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
40 CHEMISTRY
CHEMISORPTION
HYDROGEN
PLATINUM
RHODIUM
SORPTIVE PROPERTIES