NiMo/C-HY catalyst prepared from doping zeolite slurry in a superabsorbent polymer for DBT and 4,6-DMDBT hydrodesulfurization

Abstract

This study utilized the swelling properties of superabsorbent polymers (SAP) to adsorb zeolite sols and slurries to construct C-HY composites. The synthesized C-HY composites proved to be effective supports for NiMo catalysts in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT). XRD, BET, SEM, TG, NH3-TPD, FTIR, H2-TPR, TEM and XPS were used to characterization the texutural structure, acidity and metal distribution of prepared NiMo/C-HY catalysts. By combining zeolite slurries with SAPs, HY can be efficiently incorporated into carbon substrate structure in three dimensions (3D), thereby changing the structural characteristics, morphology, acidity, and metal distribution of HDS catalysts. The conversion of DBT decreases sequentially: NiMo/C-HY-s > NiMo/C-HY-h > NiMo/C-HY-p > NiMo/C-HY-c, and the conversion of 4,6-DMDBT decreased sequentially: NiMo/C-HY-s > NiMo/C-HY-p > NiMo/C-HY-h ≫ NiMo/C-HY-c. The introduction of HY into the carbon support can increase the HDS reaction rate of NiMo/C by more than 1.2–1.5 times. The intrinsic reaction activity of NiMo/C-HY-s can even exceed that of traditional NiMo/Al2O3 catalysts. Based on the same Mo loading amount, the HDS activity of NiMo/C-HY-s is twice that of NiMo/Al2O3 in DBT HDS and 1.1–1.5 times that of NiMo/Al2O3 in 4,6-DMDBT HDS. It is thought that HY in carbon composites promotes C–S bond cleavage of sulfur-containing molecules in DBT HDS. The unique dispersion of Mo species induced by HY favors the formation of highly stacked NiMoS active phases, which may be the crucial in 4,6-DMDBT HDS.