The kinetics of CO desorption from Ni(110)

Journal Article · Sun Jul 01 04:00:00 EDT 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.459532· OSTI ID:6737286

Feigerle, C S; Desai, S R ^[1]; Overbury, S H ^[2]

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1. Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600 (USA)
2. Oak Ridge National Laboratory, Oak Ridge, TN (USA)

The kinetics of CO desorption from clean Ni(110) have been measured by thermal desorption mass spectrometry (TDMS) using the method of variation of heating rates. Analysis of the desorption spectra gives the coverage dependence of the preexponential factor {nu}{sub {ital d}}, and the activation energy {ital E}{sub {ital d}}, of the desorption rate constant. For 0{lt}{theta}{lt}0.5, {ital E}{sub {ital d}} is constant at 30.6 kcal/mol, allowing analysis of the coverage dependence of the preexponential factor under conditions where the compensation effect is absent. We observe only small changes in the preexponential factor under these conditions, where log({nu}{sub {ital d}}({ital s}{sup {minus}1})) rises slowly from 14.6 to 15.3 from 0{lt}{theta}{lt}0.65. Near {theta}=0.8, a synchronous drop in {nu}{sub {ital d}} by 0.6 orders of magnitude and in {ital E}{sub {ital d}} by 5 kcal/mol is observed at the onset of formation of the (2{times}1){ital p}2{ital mg} structure. These results are discussed in light of the structures of CO in Ni(110) and the effects of ordering transitions on the desorption kinetics. The experimental results for {nu}{sub {ital d}}({theta}) are compared with those predicted for desorption by three precursor mechanisms and for desorption of a lattice gas with lateral interactions.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6737286
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 93:1; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
ELEMENTS
ENERGY
KINETICS
METALS
NICKEL
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TRANSITION ELEMENTS