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Mo<inf>2</inf>C and MoS<inf>2</inf> catalysts supported on MCM-48 for hydrodesulfurization of dibenzothiophene

Abstract:

A series of Mo2C and MoS2 catalysts supported on MCM-48 were synthesized. The active species were incorporated into the mesopore structure by two methods: a) in situ Mo(CO)6 decomposition and simultaneous sulfuration of molybdenum with elemental sulfur at 250 °C and b) conventional carburation of molybdenum oxide with CH4/H2 mixture at 700 or 800 °C for 1, 2 or 3 h, followed by sulfuration with elemental sulfur at 250 °C. The syntheses of mesoporous material type MCM-48 and of Mo2C were successful. The method (a) allowed MoS2 formation, while in the method (b) a mixture of Mo2C and MoS2 was obtained, where the proportion of MoS2 depended on the carburation conditions, its higher percentage was obtained from the sample carburated at 700 °C for 1 h. The catalyst activity in the hydrodesulfurization of dibenzothiophene depended on the proportion of MoS2 present. The simultaneous presence of both species Mo2C and MoS2 appears to enhance the catalytic activity per mass unit respect to MoS2 alone. All catalyst samples were only selective to direct hydrodesulfurization of dibenzothiophene to biphenyl.