Abstract: Photocatalytic coating technology shows important application prospects in the field of NO treatment in tunnels due to its high efficiency environmental purification ability. A Bi₂O₂CO₃@C₃N₄ junction composite photocatalyst was prepared. Under simulated visible-light irradiation, the photocatalytic degradation efficiency of NO reached 37%, which was approximately 3 times higher than pure-phase Bi₂O₂CO₃. Exploring the mechanism of improving catalytic performance through PL, UV-Vis, electrochemical and other tests. Using epoxy resin as the film-forming matrix, a low-surface-energy modifier was introduced and a rough micro-nano structure was constructed. The coating was prepared by a one-step spraying method. The microstructure, chemical composition, and thermal stability of the coating were characterized by various testing techniques. This coating has good photocatalytic activity for NO with degradation efficiency of 30%. The surface dust-removal test proves that the coating has excellent self-cleaning performance. were characterized by various testing techniques. This coating has good photocatalytic activity for NO with degradation efficiency of 30%. The surface dust-removal test proves that the coating has excellent self-cleaning performance.