γ-Al2O3-supported molybdenum nitride,molybdenum phosphide and molybdenum carbide catalysts for hydrodesulphurization were prepared,respectively,by temperature-programmed reaction.The precursors were obtained by impregnation of γ-Al2O3 in an aqueous solution of ammonium heptamolybdate tetrahydrate [(NH4)6Mo7O24·4H2O] and diammonium hydrogen phosphate [(NH4)2HPO4],followed by drying at 120 ℃ and calcining at 500 ℃ in air.The three kinds of catalysts were characterized by XRD and BET.The results indicated that the molybdenum carbide prepared at a space velocity(CH4-H2) of 10 800 h-1 has the biggest surface area of 175.7 m2/g.The pore size distribution of molybdenum nitride catalyst was complex.The small pores of about 0.622 5 nm and the big pores of about 3.736 nm were mainly observed in the supported molybdenum nitride catalyst.The active components in all of the three catalysts were dispersed on γ-Al2O3 uniformly.The conversion of dibenzothiophene on the three catalysts could respectively reach 85.5%、81% and 78.6%.
