Construction of Highly Dispersed Ni Sites on N‐rich Carbon Nitride for Enhanced Photocatalytic NO Removal

Abstract Intelligent active site engineering to harness photogenerated charge carriers and motivate surface reactions is at the core of catalysis. Herein, highly dispersed Ni sites are planted on C₃N₅, an N‐rich carbon nitride, by a facial two‐step annealing method to construct a Ni‐C₃N₅ material. The incorporation of Ni sites can significantly enhance the e^–/h⁺ separation efficiency of C₃N₅ under light irradiation and promote the activation of O₂ to produce reactive oxygen species. Compared with pristine C₃N₅ (with NO removal ratio of ≈35%), the as‐prepared 0.1‐ or 0.25‐Ni‐C₃N₅ material can remove ≈54% continuous‐flowing NO (initial concentration: 600 ppb) quickly in less than 25 min under white LED light irradiation. The long‐term photocatalytic performance demonstrates that the catalyst is stable without obvious attenuation in activity. The findings of the trapping experiments and in situ diffuse reflectance infrared fourier transform spectroscopy tests suggest that ^•O₂⁻ may mainly convert NO into NO₂, while ^•OH and ¹O₂ play a significant role in the NO₂ to NO₃^– conversion reaction. The present work brings new insights into the design of active sites on semiconductor photocatalytic materials for the treatment of NO_x species.