Catalyst as well as preparation method and application thereof

The invention discloses a catalyst as well as a preparation method and application thereof, and aims at providing the catalyst which has a simple preparation process, a wide raw material source, low cost, and relatively high effect of catalyzing heavy oil to be subjected to hydrogenation desulfurization, and also relatively high hydrogenation saturation activity on polycyclic aromatic hydrocarbon in the heavy oil. The catalyst is technically characterized in that gamma-Al2O3 is used as a carrier; by taking the mass of gamma-Al2O3 as the standard, the catalyst comprises the following components by weight percent: 4-16% of nickel and 2-12% of molybdenum. The preparation method of the catalyst sequentially comprises the following steps: (1) carrying out calcining pre-treatment on the carrier gamma-Al2O3; (2) preparing an impregnation solution containing Ni; adding the carrier gamma-Al2O3 and impregnating; drying and roasting to obtain an oxidized-state Ni-gamma-Al2O3 ball; (3) preparing an impregnation solution containing Mo, and adding the oxidized-state Ni-gamma-Al2O3 ball to be impregnated; drying and roasting to obtain an oxidized-state Ni-Mo/gamma-Al2O3 catalyst; and (4) putting the oxidized-state Ni-Mo/gamma-Al2O3 catalyst into an atmosphere of H2 gas and activating to obtain an activated-state Ni-Mo/gamma-Al2O3 catalyst. The catalyst as well as the preparation method and the application thereof belong to the technical field of treatment of the heavy oil.