Photocatalysis has been regarded as an emerging and promising air purification technology. However, nitrogen dioxide (NO₂) as the by-product is easily generated in the process of photocatalytic NO oxidation, which is more toxic and harmful to human health than NO. To inhibit the generation of NO₂ and promote the deep oxidation of No into nitrate (NO₃^-), boron nitride (BN) nanosheets was used as templates and bismuth oxybromide (BiOBr) nanosheets were introduced by the in-situ growth method to fabricate the two dimensional-two dimensional (2D-2D) BiOBr-BN photocatalysts. After introducing the BN nanosheets, the thickness and diameter of BiOBr nanosheets greatly decrease. At the same time, the specific surface area of 5% BiOBr-BN increases nearly by 15 times compared with the pure BiOBr nanosheets, which could provide more active sites for the reaction. According to the photocatalytic NO removal tests, the composites present the higher photocatalytic activity than pure BiOBr nanosheets and BN nanosheets. Among them, 5% BiOBr-BN sample reveals the best NO removal rate of 39.5%, which is higher than that of pure BiOBr nanosheets (24.6%) under visible light irradiation. More importantly, the NO₂ generation rate is suppressed from 16.4% to 7% and the oxidation selectivity of NO₃^- is increased from 36.6% to 81.5% compared with the pure BiOBr nanosheets. On the one hand, there is a strong interfacial interaction between BiOBr nanosheets and BN nanosheets, identifying by the X-ray Photoelectron Spectroscopy (XPS) and Density Functional Theory (DFT) results. Hence, 0.98 e electrons transfer from BiOBr to BN through the interface area, resulting in the formation of built-in electric field. Benefiting from this, the recombination of photogenerated charge carriers is effectively inhibited. On the other hand, BiOBr as the active surface enhances the adsorption of O₂ and promotes its activation to superoxide radicals (·O₂^-), which is proved by DFT and Electron Spin Resonance (ESR) results. As a result, the generation of toxic by-product NO₂ is effectively inhibited and NO can be directly oxidized into NO₃^-. These findings could provide a facial strategy for the design of 2D-2D photocatalysts and control of the separation of photo-generated electrons and holes.