▎ 摘　　要

NOVELTY - Preparing nitrogen-doped graphene, comprises dissolving the mask, nitrogen source and template in water, freezing and drying, and thermally decomposing under an inert atmosphere to obtain the nitrogen-doped graphene, where the material of the mask is polypropylene. The nitrogen source comprises dicyandiamide, urea and/or melamine. The template agent comprises sodium chloride, potassium chloride and/or cesium chloride. The inert atmosphere is argon or nitrogen. USE - The nitrogen-doped graphene is used as a catalyst in the electrocatalytic reduction of carbon dioxide to generate carbon monoxide (claimed). ADVANTAGE - The nitrogen-doped graphene is an ultra-thin sheet structure, because polypropylene is decomposed into small molecule at high temperature, carbonized carbon is deposited on the crystal surface of the template agent to obtain a thin sheet structure, and in-situ doped with metal element in the synthesis process, using nitrogen anchor metal site, as catalyst applied to electro-catalytic carbon dioxide reduction to generate carbon monoxide. The preparation process is simple, the preparation condition requirement is low, and the method can realize the repeated use of the mask resource. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for nitrogen-doped graphene.