Deactivation of MoS2 catalysts during the HDS of thiophene |
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Authors: | F Pedraza S Fuentes M Vrinat M Lacroix |
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Affiliation: | (1) Instituto Mexicano del Petróleo, STI, Gerencia de Catálisis, Eje Central L. Cárdenas No. 152, 07730 México D.F., Mexico;(2) Institut de Recherches sur la Catalyse, CNRS, 2 Ave. A. Einstein, 69626 Villeurbanne Cedex, France |
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Abstract: | Catalytic properties of unsupported MoS2 catalysts in the thiophene hydrodesulfurization reaction were determined in the temperature range 623–653 K. The catalysts
were prepared by ex situ decomposition of ammonium thiomolybdate (ATM) crystals in a mixture of 15% H2S in H2 at 673 K. Activity of catalysts decreased very rapidly before reaching a steady state after 15 h on‐stream. The thiophene
conversion went down from 10–12 to 3–4% in that time. The surface area of the catalysts also decreased during the catalytic
reaction from 40–50 to 8–10 m2/g. Selectivity for hydrodesulfurization, hydrogenation and isomerization reactions was affected distinctly by the deactivation
process. By increasing the reaction time, double‐bond isomerization increased, hydrogenation of butenes decreased and hydrodesulfurization
remained constant. Results indicate that the main cause of activity decay was surface area loss that was due to sintering
of MoS2 crystallites. Selectivity variation indicates that different active sites are involved for the three reactions. A deactivation
model involving diminution of active sites located in edge and rim sites of small MoS2 particles is proposed to explain the variation of product distribution.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | MoS2 deactivation thiophene HDS sintering |
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