AVS 46th International Symposium
    Surface Science Division Wednesday Sessions
       Session SS-WeP

Paper SS-WeP37
Iodobenzene Reactions and cis-1,2-Dichloroethene Chemistry on Pd(111) Studied by Laser-Induced Thermal Desorption Coupled with Fourier Transform Mass Spectroscopy (LITD-FTMS)

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: D.M. Jaramillo, University of California, Davis
Authors: D.M. Jaramillo, University of California, Davis
D.P. Land, University of California, Davis
D.E. Hunka, University of California, Davis
Correspondent: Click to Email
Halocarbons are important compounds for obtaining alkyl groups on metal surfaces. The thermal and photo dissociation of the carbon-halogen bond allows us to probe the chemistry of hydrocarbon fragments which have shown to be transient intermediates in catalytic processes. In addition, the reactions of halocarbons on metal surfaces relates to the remediation of chlorinated solvents from waste water. Elucidation of the mechanism of halocarbon decomposition will aid in determining better catalysts for remediation. The chemistry of iodobenzene and cis-1,2-dichloroethene have been investigated on Pd(111). Submonolayer iodobenzene adsorption at 90 K results in the formation of phenyl groups and iodine on the surface. The phenyl groups are hydrogenated by subsurface hydrogen to form benzene which desorbs around 500 K. Higher exposures of iodobenzene show iodobenzene desorbing at 200 K and benzene observed only at 140 K. The adsorbed iodine changes the reactivity of iodobenzene. Molecular desorption of cis-1,2-dichloroethene occurs at 160 K for low exposures and at around 200 K for higher exposures. Hydrogen is seen to desorb around 300 K for even the lowest exposure studied. No HCl was observed in TDS or LITD.