Hydrodesulfurization of 4,6-DMDBT on a multi-metallic sulfide catalyst with layered structure

A multi-metallic NiAlMoW catalyst with layered structure was prepared by surfactant-assisted co-precipitation method using NiAl-layered double hydroxide (NiAl-LDH) as the structure-directing template. By carefully tuning the composition of the layered structure and the synthesis conditions, we have prepared a series of NimAlnMoW catalysts. For the HDS of 4,6-DMDBT, NiAl3MoW-5 shows two times higher intrinsic catalytic activity (based on weight of active metals) compared to that of the commercial CoNiMoW/Al2O3 catalyst. The sulfur content in the model compound could be reduced from 500 ppm to less than 20 ppm using this catalyst under the operation conditions of 3.0 MPa, 300 °C, a WHSV (weight hourly space velocity) of 9 h−1, and H2/oil ratio of 800 Nm3/m3. The synthesized catalysts were characterized by SEM, TEM, XRD, TG/DSC, nitrogen adsorption/desorption isotherms and XRF. This NiAlMoW catalyst has retained the unique layered structure of NiAl-LDH, which can facilitate uniform dispersion of the active species on both the surface and the edge of the layer. It was found that the layered structure has a great impact on the catalytic activity of the HDS reactions.