The adsorption of sulfur and halogen containing materials on nickel studied by X-ray photoelectron spectroscopy and thermal desorption spectroscopy

The chemical adsorption and reaction of methyl fluoride, methyl chloride, methyl bromide, methyl iodide, methyl sulfide, dimethyl sulfide, dimethyl disulfide, and bis(trifluoromethyl) disulfide on clean, polycrystalline nickel surface (at 25°C) were investigated using an X-ray photoelectron spectrometer (XPS) and a thermal desorption system with mass spectrometric analysis (TD). The ion implantation of the methyl halide series on nickel was investigated by XPS. The nickel surface was cleaned by high temperature heating in vacuum or argon ion sputtering. An industrial lubricant, FC-43 (tri-hepta-fluorobutyl amine), was adsorbed on a gold-plated nickel surface at 25°C. Tne FC-43 adsorption system was investigated by TD. The adsorption of the methyl halide series on nickel was predominantly dissociative with several co-existing surface species being observed. The XPS results show that two carbon and two halogen species are formed. The possible structures for carbon are a CH₃-type and a CH₂-type or CH_nX (n = 0-3) adsorbed species. The halogen species appear to be neutral and ionic species. The TO results support the dissociative adsorption process for methyl halides on nickel. The adsorption of methyl fluoride and methyl chloride on nickel studied by TD resulted in the corresponding nickel halide being detected. The adsorption of methyl bromide and methyl iodide on nickel studied by TO resulted in the corresponding hydrogen halide, HX, being detected. The XPS results of the ion implantation of the methyl halides resulted in only one type of carbon that is similar to graphite. A halide type of halogen was also formed upon ion implantation. The XPS results for the adsorption of methyl sulfide, dimethyl sulfide, and dimethyl disulfide on nickel showed that only one carbon and one sulfur were observed. The possible structure for carbon is a CH₃-type of adsorbed specie. lhe sulfur species appears to be a sulfide S⁼-type adsorbed specie. The XPS results for the adsorption of bis(trifluoromethyl) disulfide on nickel showed that only sulfur was observed on the nickel surface. The TD results- for the methyl sulfide adsorption process was shown to be predominantly an associative type. The TO results for the dimethyl sulfide adsorption process were a mixture of dissociative and associative adsorption processes. The dimethyl disulfide adsorption process was determined by TD to be predominantly a dissociative type. The bis(trifluoromethyl} disulfide was determined by TD to be completely dissociative upon adsorption and reacted with nickel to form nickel sulfide. The TD results of FC-43 adsorption on gold-plated nickel showed that the predominant adsorption process was the associative type.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1976

Author dc:creator

• Battrell, Charles Frederick

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/81023

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/81023