Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/95240
Title: The interaction of Ni and Fe with sulfur and molybdenum-sulfide surfaces: A TDS, XPS and hydrogen-chemisorption study
Authors: Rodriguez, J.A.
Li, S.Y.
Hrbek, J.
Huang, H.H. 
Xu, G.-Q. 
Keywords: Hydrogen
Hydrogen sulphide
Iron
Molybdenum
Nickel
Sulphides
Surface chemical reaction
Thermal desorption spectroscopy
X-ray photoelectron spectroscopy
Issue Date: 1-Jan-1997
Citation: Rodriguez, J.A.,Li, S.Y.,Hrbek, J.,Huang, H.H.,Xu, G.-Q. (1997-01-01). The interaction of Ni and Fe with sulfur and molybdenum-sulfide surfaces: A TDS, XPS and hydrogen-chemisorption study. Surface Science 370 (1) : 89-95. ScholarBank@NUS Repository.
Abstract: Sulfur multilayers, containing Sn species (n=2, 4, and 8), are very reactive toward admetals like nickel and iron. Ni and Fe atoms supported on sulfur films at 200-300 K exhibit core-level binding energies and band structures very similar to those of nickel and iron sulfides. In contrast, Ni atoms supported on molybdenum-sulfide surfaces remain in a metallic state. NiMoS and FeMoS films can be generated by heating Ni/Sfilm/Mo(110) and Fe/Sfilm/Mo(110) systems to high temperature. The behavior of the Ni/Sfilm/Mo(110) and Fe/Sfilm/Mo(110) systems indicates that Ni and Fe promote Mo↔S interactions and the subsequent formation of molybdenum sulfides. On TM/MoSx and TM/S/Mo(110) surfaces (TM=Ni or Fe), the slow step in the D2,gas+Ssolid→D2Sgas reaction is the dissociation of molecular hydrogen. Ni/MoSx and Fe/MoSx surfaces interact strongly with atomic hydrogen (D), sorbing this element and forming gaseous hydrogen sulfide. The sorption of D produces uniform changes in the electronic properties of the MoSx substrate, with positive binding energy shifts (0.3-0.4 eV) in the core levels of molybdenum and sulfur. Most of the sorbed hydrogen evolves into gas phase as D2 at temperatures between 350 and 500 K. Trends seen in the hydrodesulfurization activity of NiMoS and FeMoS catalysts are analyzed following our results for the sulfidation of Mo and the hydrogenation of S in NiMoS and FeMoS films.
Source Title: Surface Science
URI: http://scholarbank.nus.edu.sg/handle/10635/95240
ISSN: 00396028
Appears in Collections:Staff Publications

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