Co(Ni)/MoS2 nanostructured catalysts for the hydrodesulphurization of dibenzothiophene.

In this study Co(Ni)/MoS2 unsupported nanocatalysts (nanorods and nanoribbons) were synthesized with Co(Ni)/(Co(Ni) + Mo) = 0.3, 0.5 molar ratios for Co and Ni respectively. First the alpha-MoO3 nanostructures were impregnated with an aqueous solution of Co(Ni)Cl2 x 6H2O or Co(Ni)(NO3)2 x 6H2O, then were treated for 2 h at 473 K, and finally the precursors were activated under a H2S/H2 mixture (15% v/v H2S) by ramping the temperature from room temperature to 773 K and keeping it at that value for 2 h. The resulting materials were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, specific surface area and X-ray photoelectron spectroscopy, and tested as catalysts for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). It was found that these materials presented specific surface areas below 25 m2/g. The catalytic test showed that only when Co is added a promoter effect is observed compared with MoS2 unpromoted catalysts. Among the materials prepared, the Co/MoS2 catalyst made from cobalt chloride presented the highest catalytic activity (6.95 mol s(-1) g(-1)catalyst) for the HDS of DBT. The selectivity for the latter indicated a clear preference for the direct desulphurization over the hydrogenating pathway.