Catalytic hydrodesulfurization over the Mo(100) single crystal surface. II. The role of adsorbed sulfur and mechanism of the desulfurization step

Journal Article · Tue Sep 01 04:00:00 EDT 1987 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(87)90276-4· OSTI ID:5204339

Gellman, A J; Bussell, M E; Somorjai, G A

The study of thiophene hydrodesulfurization (HDS) over initially clean Mo(100) surfaces has been extended to include sulfided surfaces. Low sulfur coverages (0 less than or equal to theta/sub s/ < 0.67) inhibit HDS activity. Increasing the sulfur coverage in the range 0.67 less than or equal to theta/sub s/ less than or equal to 1.0 produces a surface with an HDS activity of about half that of the clean Mo(100) surface. Excessive exposure of the surface to a sulfur-containing environment results in the formation of a MoS/sub 2/ layer which is, at least in part, responsible for complete catalytic deactivation. Radiotracer (/sup 35/S) labeling techniques have been used to measure rates of hydrogenation of sulfur adsorbed on the Mo(100) surface. In ambient atmospheres of both hydrogen (1 atm) and the thiophene HDS reaction mixture (P(H/sub 2/) = 1 atm, P(Th) = 2.5 Torr) the rate of hydrogenation of adsorbed sulfur is two orders of magnitude less than the HDS rate. This fact has been used to suggest that the desulfurization step of the reaction does not proceed via the formation of a tightly bound Mo-S species. 24 references

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5204339
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 107:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

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