免焙烧制备Ni 2 P/SiO 2 加氢脱硫催化剂

Ni2P/SiO2 hydrodesulfurization(HDS)catalysts were prepared by a non-calcination method,in which the precursors containing Ni(NO3)2 and(NH4)2HPO4 were directly converted to the active phosphide phase through the temperature-programmed reduction(TPR)procedure.The HDS performances of the prepared Ni2P/SiO2 catalysts were studied with a model fuel containing 0.8%(mass fraction)dibenzothiophene in decalin,and the morphologies of the catalysts were characterized by XRD.The results indicated that the monolayer dispersion threshold of the Ni2P/SiO2 catalysts prepared by the non-calcination method was between 15%-25%(mass fraction).The increase of the active component loading in Ni2P/SiO2 catalyst led to the increase of HDS activity and the decrease of the direct desulfurization pathway selectivity.However,further increase in the active component loading would not affect the particle sizes and HDS activity of the catalyst,when the loading was above the monolayer dispersion threshold.The catalyst prepared by the non-calcination method exhibited a good stability during HDS reaction,and its HDS activity was equal to(when the loading was above the monolayer dispersion threshold)or higher than(when the loading was less than the monolayer dispersion threshold)that of the catalyst prepared by conventional method.The heating program in the TPR method was a key parameter affecting the HDS activity of Ni2P/SiO2.The heating rate at lower temperature region hardly affected the HDS performance of the catalyst,while holding at 400℃ for a short period had a positive action to its HDS activity.