The invention discloses a composite catalyst, a preparation method and application thereof. The composite catalyst comprises an MXene substrate,
rhenium disulfide nanosheets loaded on the surface of the MXene substrate and doped with
nonmetal atoms, and
platinum monoatoms loaded on the
rhenium disulfide nanosheets doped with the
nonmetal atoms. According to the invention,the loaded
platinum single atoms can realize high atom utilization efficiency, greatly reduce the use amount of
platinum and save the cost; the
rhenium disulfide
nanosheet has a large surface area and can contain more platinum atoms, and by conducting non-
metal atom
doping on the rhenium disulfide
nanosheet,the number of active sites of the rhenium disulfide
nanosheet can be increased, and the
conductivity and the
proton capturing capacity of the rhenium disulfide nanosheet are improved; the MXene material is introduced, so that the number of active sites of the rhenium disulfide nanosheet is increased, and the
conductivity of the rhenium disulfide nanosheet is improved; and the MXene substrate and the rhenium disulfide nanosheet loaded on the surface of the MXene substrate and doped with
nonmetal atoms are integrally used as a platinum monatomic carrier to realize loading of platinum monatomic, so that the composite catalyst has excellent electro-catalytic performance.