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Title: Comparison of benzene adsorption on Ni(111) and Ni(100)

The adsorption of benzene on the Ni(100) and the Ni(111) crystal faces was compared in order to investigate the effect of crystallographic orientation on the interaction of benzene with nickel. Temperature programmed reaction (TPR) was used to characterize adsorption bond strengths and determine product distributions. Benzene was found to adsorb 44 kJ/mol less strongly on the Ni(111) plane than on the Ni(100) surface. Di-hydrogen evolution formed after decomposition of benzene was similar for both surfaces. Benzene chemisorption was modeled by using extended Hueckel theory (EHT), a semiempirical molecular orbital method. The calculations predict bonding of benzene over a threefold hollow site on Ni(111). Multicenter bonding of the benzene carbon atoms with the nickel atoms is indicated by the calculations. The binding strength of benzene is controlled by the degree of overlap of the carbon ..pi.. orbitals with the nickel atom orbitals. Benzene binds more strongly to the Ni(100) surface because the carbon ..pi.. orbitals can overlap with four nickel atoms on the fourfold hollow site, whereas on Ni(111) the carbon atoms are closely associated with only three nickel atoms on the threefold hollow site.
Authors:
; ;
Publication Date:
OSTI Identifier:
6541021
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Phys. Chem.; (United States); Journal Volume: 91:9
Research Org:
Princeton Univ., NJ
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BENZENE; CHEMISORPTION; ELECTRONIC STRUCTURE; NICKEL; CATALYTIC EFFECTS; SORPTIVE PROPERTIES; EXPERIMENTAL DATA; HIGH TEMPERATURE; HYDROGEN; LOW TEMPERATURE; MASS SPECTROSCOPY; MEDIUM TEMPERATURE; MILLER INDICES; MONOCRYSTALS; AROMATICS; CHEMICAL REACTIONS; CRYSTALS; DATA; ELEMENTS; HYDROCARBONS; INFORMATION; METALS; NONMETALS; NUMERICAL DATA; ORGANIC COMPOUNDS; SEPARATION PROCESSES; SORPTION; SPECTROSCOPY; SURFACE PROPERTIES; TRANSITION ELEMENTS 400201* -- Chemical & Physicochemical Properties