Fundamental study of catalysts using laser Raman, infrared, auger electron spectroscopy and low energy electron diffraction. Progress report, April 1981-November 1982. [Carbon monoxide methanation with nickel catalyst]

Technical Report · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6788316

Bradley, E B; Sargent, G A

Raman spectra of CO adsorbed on Ni(111) have been recorded from -174/sup 0/C to 26/sup 0/C. Raman spectra are also recorded for CO + H/sub 2/ on Ni(111) at temperatures from 200 to 530/sup 0/C. The Raman band corresponding to physadsorbed O/sub 2/ on Ni(111) occurs at 1555 cm/sup -1/ when O/sub 2/ is adsorbed below 290/sup 0/K, and no Ni-0 mode is observed. A theory of surface enhanced Raman scattering (SERS) has been refined and it explains most of the reported Raman data on SERS. The benefit to catalyst studies lies in the possibility of a surface with atomic-scale roughness features amplifying Raman signals of adsorbates. A study of CH/sub 4/ on the Ni single crystals shows no evidence of chemical bonding. Only slight frequency shifts from gas phase modes are observed. The thermal desorption of CO, O/sub 2/ and CH/sub 4/ molecules was studied by LEED, Auger Electron Spectroscopy (AES) and Mass Spectroscopy. The data on the desorption of CO was found to agree with that of other workers, although an additional high temperature peak was observed on the surface having the small angle boundaries. Two desorption peaks were observed for O/sub 2/ from the nickel surfaces. The low energy peak was thought to be due to physisorbed O/sub 2/ and this hypothesis appears to be supported by the laser Raman work. The higher energy peak appears to be associated with chemisorbed O/sub 2/. There was some indication that O/sub 2/ may dissolve into the bulk Ni. Two desorption peaks were found for CH/sub 4/, both of which were very small, implying that they involved physisorbed molecules. It was concluded that one peak was associated with small angled boundary states.

• Research Organization: Kentucky Univ., Lexington (USA). Coll. of Engineering
• DOE Contract Number: AS05-79ER10447
• OSTI ID: 6788316
• Report Number(s): DOE/ER/10447-3; ON: DE83006758
• Country of Publication: United States
• Language: English

Related Subjects

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ADSORPTION
ALKANES
AUGER ELECTRON SPECTROSCOPY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
DESORPTION
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
HYDROCARBONS
HYDROGEN
INFRARED SPECTRA
LASERS
MASS SPECTROSCOPY
METALS
METHANATION
METHANE
NICKEL
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
RAMAN SPECTRA
RESEARCH PROGRAMS
SCATTERING
SORPTION
SORPTIVE PROPERTIES
SPECTRA
SPECTROSCOPY
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS