Oxide-molecular sieve composite catalyst as well as preparation method and application thereof

The invention provides an oxide-molecular sieve composite catalyst and a preparation method and application thereof.The preparation method comprises the steps that a rare earth modified copper molecular sieve, water, a thickening agent, a binder and a metal oxide precursor are mixed, the pH is adjusted, and slurry is obtained; coating a carrier with the obtained slurry, drying and roasting to obtain a metal oxide-molecular sieve composite catalyst; the metal oxide precursor comprises any three or a combination of more than three of Fe salt, Ce salt, Sm salt, Ni salt or Co salt; according to the preparation method, through a slurry preparation method, a metal oxide with specific components is introduced on the basis of a modified copper molecular sieve for composite modification treatment, and the prepared metal oxide-copper molecular sieve composite catalyst greatly reduces the generation amount of N2O under the condition that the NO conversion efficiency is guaranteed, and meanwhile, the generation amount of