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Mo2C and MoS2 catalysts supported on MCM-48 for hydrodesulfurization of dibenzothiophene

Abstract:

A series of Mo<inf>2</inf>C and MoS<inf>2</inf> catalysts supported on MCM-48 were synthesized. The active species were incorporated into the mesopore structure by two methods: a) in situ Mo(CO)<inf>6</inf> decomposition and simultaneous sulfuration of molybdenum with elemental sulfur at 250 °C and b) conventional carburation of molybdenum oxide with CH<inf>4</inf>/H<inf>2</inf> 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 Mo<inf>2</inf>C were successful. The method (a) allowed MoS<inf>2</inf> formation, while in the method (b) a mixture of Mo<inf>2</inf>C and MoS<inf>2</inf> was obtained, where the proportion of MoS<inf>2</inf> 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 MoS<inf>2</inf> present. The simultaneous presence of both species Mo<inf>2</inf>C and MoS<inf>2</inf> appears to enhance the catalytic activity per mass unit respect to MoS<inf>2</inf> alone. All catalyst samples were only selective to direct hydrodesulfurization of dibenzothiophene to biphenyl.