Synthesis of NiMo catalysts supported on mesoporous Al-SBA-15 with different morphologies and their catalytic performance of DBT HDS

Mesoporous SBA-15 materials with different morphologies were successfully synthesized through different methods by using pluronic P123 triblock copolymer (EO20PO70EO20) and cosurfactant (CTAB) as structure-directing agent. Moreover, highly ordered mesoporous Al-SBA-15 with a Si/Al molar ratio of 10 has been prepared with three different Al resources using post-synthesis methods. The characterization results of X-ray fluorescence spectroscopy, X-ray power diffraction, N-2 adsorption-desorption and Al-27 nuclear magnetic resonance spectroscopy revealed that the chemical grafting of aluminum chloride on the surface of SBA-15 was the best post-synthesis route for the preparation of Al-SBA-15 with different morphologies. The corresponding Al-SBA-15-supported NiMo hydrodesulfurization (HDS) catalysts with different morphologies were prepared and evaluated using DBT as a probe reactant. The sphere NiMo/AS-SP catalyst has higher dispersion degree of MoS2 slabs and more acid sites than other catalysts. The catalytic results showed that the morphologies and mesochannels of SBA-15 played an important role in the catalytic performance of DBT HDS over NiMo catalysts, especially in the diffusivity of DBT molecules in the catalysts, while they have little effect on the selectivity of DBT HDS. The kinetics investigations confirmed that the activity of DBT HDS over these catalysts followed the order: long-rod catalyst (NiMo/AS-LR)< hexagonal prism catalyst (NiMo/AS-HP) < short-rod catalyst (NiMo/AS-SR) < sphere catalyst (NiMo/AS-SP). The high activity of the last one was attributed to the superior diffusion of the supports and the better dispersion of the active components. (C) 2014 Elsevier B.V. All rights reserved.