Nb modified mesoporous SBA-15 and HMS materials were synthesized and studied as a support of NiMo. Calcined co-impregnated NiMo catalysts were prepared using ammonium heptamolybdate and nickel nitrate. Moreover, NiMo catalysts prepared in this manner were treated with thioglycolic acid (TGA). For comparison, NiMo catalysts were prepared by a simultaneous impregnation of the supports with Ni, Mo precursors and TGA. The TGA:Mo molar ratio was 4.0. The supports and NiMo catalysts were characterized by N-2 physisorption, small- and wide-angle XRD, TPD-NH3, SEM, UV-vis DRS, FTIR and XPS. Catalyst activity was examined in hydrodesulfurization (HDS) reactions of 1-benzothiophene and thiophene at 350 degrees C. It was found that simultaneous impregnation by Ni, Mo and TGA led to higher HDS activities than the sequential treatment of the calcined NiMo catalysts by TGA. (C) 2016 Elsevier B.V. All rights reserved.