Abstract: The impregnating solution of Mo-Ni-Pprepared by using MoO₃·H₂O, NiCO₃, H₃PO₄ without the impurities of Na⁺ and NH₄⁺ is better than that made from MoO₃, 2NiO(OH)₂·Ni/CO₃ and H₃PO₄ and no precipitation is found for being kept for a long time. According to the results of amonia-dissolving and XRDexperiments, a solubility threshold of Mo or Ni component on the support is found and the Mo/Ni mole ratio is 0. 8:1 after ammonia-dissolving. Component Pcan suppress the interaction of the support with the compound of Mo and Ni on the surface of the support. The TPRresults reveal that the suppression of the reduction of NiOby component Pis reduced by the interaction of Pwith support, and the reduction temperature of MoO₃ can also be decreased by the inrteraction between the compound of Mo and support. In addition, a suitable load amount of Mo-Ni-Pimpregnating solution is given.

Key words: Mo-Ni-P/γ-Al₂O₃ catalyst, Mo-Ni-P impregnating solution, γ-Al₂O₃ support