Thiophene hydrodesulfurization using β-Mo2C/MCM-41 as catalyst

Samples of Al-MCM-41 (Si/AI = 20) and Si-MCM-41 molecular sieves were impregnated with ammonium heptarnolybdate solutions using the incipient wetness method in order to have a MoO3 loading of 21 wt%. P-Mo2C supported on Al-MCM-41 and Si-MCM-41 was obtained by carburizing the oxide samples using the Temperature-Programmed Carburization (TPC) methodology with a 20%(v/v) CH4/H-2 mixture. The carburized samples were tested as hydrotreating (HDT) catalysts employing the hydrodesulfurization (HDS) of thiophene at different temperatures as model reaction. The activity results obtained at atmospheric pressure show that A1 incorporation to the MCM-41 framework led to a twofold increase in the catalytic activity. For the experiments at high pressure (3 MPa) the results reveal that while beta-Mo2C supported on Si-MCM-41 presented a decrease in activity with time on stream, the beta-Mo2C supported on Al-MCM-41 was quite stable along twenty hours on stream.