Preparation method and application of carbon nitride photocatalyst

The invention discloses a preparation method and application of a carbon nitride photocatalyst, and particularly relates to the technical field of photocatalyst functional materials. The preparation method of the carbon nitride photocatalyst comprises the following steps: S1, mixing a carbon nitride precursor and a copper source, and dispersing the mixture on a carrier; s2, calcining the carrier obtained in S1, a carbon nitride precursor and a copper source together to obtain a carbon nitride photocatalyst; the molar ratio of the carbon nitride precursor to the copper source in the step S1 is (12.5-100): 1. The copper single atoms and the nitrogen element of the carbon nitride form covalent bonds, the structure of the carbon nitride is changed, the surface active sites and the contact area of the carbon nitride are increased, the loading capacity of the carbon nitride on the carrier is increased, and the copper single atom anchored carbon nitride has a unique flower-shaped structure and has a large specific s