Synthesis of Ni-Mo-W sulfide nanorods as catalyst for hydrodesulfurization of dibenzothiophene.

Two trimetallic sulfurs, MoWNiS and MoWSNi, were synthesized to be used as a catalyst in hydrodesulfurization reactions. The mixed oxide mesoporous nanostructured MoO3 -WO3 with an Mo:W atomic ratio of 1:1 was used as the precursor. The first catalyst was prepared by impregnating nickel in the oxide precursor and then subsequent sulfiding with an H2S/H2 mix at 400 degrees C for 2 hours. The second catalyst was prepared by sulfiding the precursor and then impregnating the nickel, and finally reducing the material with a H2/N2 at 350 degrees C. In both catalysts the Mo:W:Ni atomic ratio was maintained at 1:1:0.5. The materials obtained were characterized by physical adsorption of nitrogen, X-ray diffraction, scanning electron microscopy, transmission electron microscopy. Furthermore, the materials obtained were evaluated by a dibenzothiophene hydrodesulfuration reaction. The diffraction patterns show that both materials are polycrystalline and mainly of MoS2 and WS2 phases.

Synthesis and characterization of porous Mo-W oxide nanostructures.

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 degrees C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 degrees C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.