Effect of sodium doping on the structure and enhanced photocatalytic hydrogen evolution performance of graphitic carbon nitride

Construction of high-efficiency photocatalysis for hydrogen evolution has long been regarded as the significative and challenging work. Herein, we developed a facile ball milling combined calcination method to synthesize a series of sodium-doped graphitic carbon nitride (g-C 3 N 4 ) with different sodium content. The as-prepared samples were characterized by various techniques and applied in hydrogen production under visible-light irradiation. Results showed that the incorporation of sodium would have certain effect on the intrinsic properties of g-C 3 N 4 . The optimal sample with about 3.09   At% of sodium exhibited the highest photoactivity, the hydrogen production rate (176.0   μmol   h −1   g −1 ) of which was about 9.9 times higher than that of pure g-C 3 N 4 (17.8   μmol   h −1   g −1 ). The tremendously enhanced photoactivity could be ascribed to the expanding visible light absorption and immensely increased separation efficiency of photo-generated charge carriers. Therefore, this study proposes an effective route to synthesize sodium doping g-C 3 N 4 , which is promising for further practical applications in environmental issues.