MOR nanosheet assemblies supported NiW catalysts in the hydrodesulfurization of the 4,6-DMDBT: Effect of Ni/W ratio on the catalytic performance

Abstract

The preparation of highly active hydrodesulfurization (HDS) catalyst is of vital importance for the production of ultra-clean fuel. Herein, nanosheet assemblies MOR were employed as support to prepare series of NiW catalyst with different Ni/W ratio (NiW/NS-MOR). After impregnation of Ni and W species and sulfidation, the obtained NiW/NS-MOR catalyst showed an increasing activity in the HDS of the refractory 4,6-dimethyldibenzothiophene with the rise of the Ni content in the prepared NiW catalysts, and reached the maximum HDS activity at the Ni/W ratio of 0.55. Also, the reaction rate constant and TOF on NiW/NS-MOR-0.55 (11.1 × 10−4 mol g−1 h−1 and 3.3 h−1) were much higher than those on NiW/γ-alumina catalyst (8.1 × 10−4 mol g−1 h−1 and 2.2 h−1). All the prepared supported-NiW catalysts were characterized by N2 physisorption, X-ray powder diffraction, Ultraviolet visible spectroscopy, Raman spectroscopy, temperature-programmed reduction by H2, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. Characterization results show that the increase in Ni/W for the prepared catalyst weakened the interaction of the tungstate oxide species with NS-MOR, and then more tungstate oxide species were transformed into stacked and highly active Type II NiWS active phase, improving the HDS activity of the catalyst.