Effect of sulfidation on Mo-W-Ni trimetallic catalysts in the HDS of DBT

Abstract

This work presents the effect of different sulfiding agents on Mo-W-Ni trimetallic catalysts, such as “NEBULA” catalysts. The materials were prepared by direct precipitation of ammonium molybdate, ammonium tungstate and nickel nitrate, generating a trimetallic precursor designated NH 4-Ni-Mo 0.5W 0.5-O. Hydrogen sulfide (H 2S), dimethyl disulfide (DMDS) and dimethyl sulfide (DMS) in a hydrogen atmosphere were used to sulfide the precursor at 400 °C for 2 h. The NE B H 2 S , NEB DMDS and NEB DMS catalysts obtained were evaluated in the hydrodesulphurization (HDS) reaction of dibenzothiophene (DBT). DMDS and DMS are less polluting agents than H 2S, which is indeed a highly toxic compound. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, textural properties were measured using the BET and BJH methods. NE B H 2 S and NEB DMDS catalysts present similar catalytic activities for HDS, higher than NEB DMS. However, the latter catalyst was the most selective towards biphenyl (BF). NE B H 2 S and NEB DMDS catalysts were exposed twice to the HDS reaction, they presented an improvement in catalytic activity compared to the first catalytic test.