A new multi–metallic bulk catalyst with high hydrodesulfurization activity of 4,6–DMDBT prepared using layered hydroxide salts as structural templates

• New multi-metallic bulk catalysts NixZnyMoW with layered structure were prepared based on layered hydroxide salts.
• The HDS activity of 4,6-DMDBT on these catalysts was found to be much higher than that of the commercial catalyst CoNiMoW/Al2O3.
• Adding Zn to catalyst NiMoW can enhance the HDS activity.
• The layered structure has an effect on the HDS activity of catalysts.

Layered multi–metallic bulk catalysts NixZnyMoW with different Ni/Zn molar ratios were prepared based on the NiZn–layered hydroxide precursor by co–precipitation method and well characterized by various technologies including XRD, SEM, HRTEM and Raman spectroscopy. HRTEM images illustrated that both the slab sizes and stacking layers of sulfided catalysts were changed with different Zn contents. These catalysts were tested for hydrodesulfurization (HDS) of 4,6–dimethyldibenzothiophene (4,6–DMDBT) from model diesel. Hydrodesulfurization (HDS) reaction of 4,6–dimethyldibenzothiophene showed that all the catalysts NixZnyMoW with layered structure exhibited high HDS activity and the sulfur content in the model diesel can be reduced from 517 ppm to less than 10 ppm under mild reaction conditions of 3.0 MPa of H2 pressure, 300 °C, a LHSV of 9 h−1, and H2/oil ratio of 800 N cm3/cm3. The catalysts NixZnyMoW have shown much higher specific HDS activity than that of the commercial catalyst CoNiMoW/Al2O3. However, ZnMoW without Ni has shown relatively low activity. The higher HDS activity of NixZnyMoW could be ascribed to high contents of active metals and the layered structure. Meanwhile, the synergism between Ni/Zn and Mo/W plays an important role in achieving the excellent HDS performance of catalysts NixZnyMoW.

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