Structure and Hydrodesulfurization Performances of Ni_2P/SBA-15 Catalysts

The samples containing nickel phosphide precursors were synthesized by co-impregnation method using mesoporous molecular sieve SBA-15 as support, nickel nitrate as nickel source, and (NH4)2HPO4 as phosphorus source. Then, the Ni2P/SBA-15 catalysts with different Ni2P contents were prepared by temperature-programmed reduction method in H2 flow. The structure of the catalysts was characterized using X-ray diffraction (XRD), N2 adsorption/desorption, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) techniques. The catalytic performances of hydrodesulfurization (HDS) were evaluated in a fixed-bed micro-reactor using thiophene and dibenzothiophene (DBT) as the model compounds. The results indicated that the mesoporous structure of SBA-15 was still preserved in the Ni2P/SBA-15 catalysts. The active component Ni2P was well dispersed on the surface of the catalysts. The BET surface area, pore volume, and pore diameter decreased obviously with the increase of Ni2P loading. The Ni2P/SBA-15 catalysts had the better catalytic performance at 320 ℃ when Ni2P loading was from 15% to 25% (w, mass fraction) . All of the catalysts showed an excellent deep HDS performance when reaction temperature was higher than 360 ℃. The mechanism of the HDS of DBT was the main direct desulfurization (DDS) over the Ni2P/SBA-15 catalysts.