One-pot synthesis of ordered mesoporous NiMo-Al2O3 catalysts for dibenzothiophene hydrodesulfurization

Ordered mesoporous NiMo-Al2O3 catalysts with 20.0 wt.% MoO3 and various NiO contents were synthesized by a facile one-pot evaporation-induced self-assembly (EISA) method, using P123 as structure-directing agent and anhydrous ethanol as solvent. The hydrophilic Al-, Ni-, and Mo-containing compounds surrounded the P123 micelles to form a hexagonal mesoporous structure. The NiMo-Al2O3 catalysts were characterized by a series of techniques, including N-2 adsorption, XRD, XRF, TEM, SEM, FTIR, TG-DSC (for the as-synthesized NiMo-Al2O3 precursors), and TPR. The catalytic activities were tested in hydrodesulfurization (HDS) of dibenzothiophene (DBT). Results show that calcination at 500 degrees C can fully remove the surfactant and solvent to form amorphous walls. Molybdenum and nickel atoms were incorporated into the channels of the ordered mesoporous alumina and highly dispersed, maintaining the hexagonal symmetry mesostructures. Incorporations of Ni promoted a transformation of molybdate from tetrahedral to octahedral sites and changed the relative intensities of the TPR peaks. Catalytic results reveal that the ordered mesoporous NiMo-Al2O3 catalysts had high activities towards DBT. Biphenyl was the abundant product in HDS reactions, and direct desulfurization was the dominant route. A high HDS activity was observed with a Ni/Mo molar ratio of 1:1, which was attributed to more easily reducible molybdate and better dispersion of the MoS2 nanoparticles. The ordered mesoporous NiMo-Al2O3 catalysts, synthesized by this facile one-pot EISA method, provide a new alternative for industrial HDS process. (C) 2016 Elsevier B.V. All rights reserved.