The role of adatoms (C,S) and surface structure in thiophene hydrodesulfurization over transition metal surfaces: A surface science and catalytic study

Technical Report · Mon Aug 01 04:00:00 EDT 1988

DOI:https://doi.org/10.2172/6085390· OSTI ID:6085390

Bussell, M. E.

Thiophene Hydrodesulfurization (HDS) has been studied over transition metal single crystal (Mo, Re) and polycrystalline foil (Co, Mo, Re) surfaces using a combined ultrahigh vacuum/catalytic reactor apparatus. The metal surfaces were cleaned, modified and characterized in ultrahigh vacuum (1 /times/ 10/sup /minus/9/ Torr) prior to high pressure (1 atm) catalytic reactions carried out in an in-situ isolation cell. The influence of catalyst surface structure on thiophene HDS was investigated by carrying out reactions over surfaces of different crystallographic orientation and the role of adsorbates examined using radiotracer /sup 14/C and /sup 35/S isotopes. Thiophene HDS is a structure insensitive reaction over molybdenum surfaces, but a structure sensitive reaction over rhenium surfaces. The HDS reaction over molybdenum occurs on a strongly bound adsorbate overlayer composed primarily of carbidic carbon. In contrast, HDS of thiophene over rhenium surfaces occurs directly on the metal surface. The ability of the rhenium surfaces to remain free of strongly bound deposits of carbon and/or sulfur makes them more active (by a factor of 1--6 times) than the molybdenum surfaces studies. For both metals, deactivation at high conversions is caused by product inhibition (H/sub 2/S). Thiophene HDS studies over Co, Mo and Re foils reveal a trend in catalytic activity similar to that found in the literature for the sulfides of these metals. This suggests that metal single crystals and polycrystalline foils are suitable catalysts for model studies of HDS.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6085390
• Report Number(s): LBL-25824; ON: DE89010380
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AUGER ELECTRON SPECTROSCOPY
CARBON
CATALYTIC EFFECTS
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL STRUCTURE
DESULFURIZATION
DIFFRACTION
ELECTRON DIFFRACTION
ELECTRON SPECTROSCOPY
ELEMENTS
HETEROCYCLIC COMPOUNDS
LABELLING
METALS
MOLYBDENUM
NONMETALS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PRESSURE DEPENDENCE
RHENIUM
SCATTERING
SPECTROSCOPY
SULFUR
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THIOPHENE
TRANSITION ELEMENTS