Na-doped nitride-rich carbon nitride for efficient photocatalytic NO abatement

Nitride-rich carbon nitride (C₃N₅) is gaining prominence as a substantial catalyst for photocatalytic reaction because of its narrow bandgap, extensive light responsiveness, and photocatalytic stability. To enhance the efficiency of photogenerated carrier separation in C₃N₅, we propose a strategy for Na-doped modification. Photocatalytic NO removal efficiency of C₃N₅/Na achieved 73.9 % under 15 % relative humidity, which is 3.5 times higher than that of C₃N₅. Besides, the NO removal efficiency of C₃N₅/Na maintained above 70 % even after six cycles under different relative humidities. Detailed analytical characterization revealed that Na doping of C₃N₅ not only increased its specific surface area by 5.5-fold but also modulated its energy band structure and molecular structure, leading to improved hole-carrier separation efficiency and enhancing the photocatalytic performance of C₃N₅/Na. ESR and reactive species trapping experiments confirmed that electrons and superoxide are the main reactive species, and modulation of the energy band structure accelerates the reaction. This work explains the effect of Na doping on C₃N₅ and provides a new strategy for designing efficient for photocatalytic treatment of air pollution.