Oxygen doped g-C₃ N₄ with nitrogen vacancy for enhanced photocatalytic hydrogen evolution

Generally, bulk graphic carbon nitride (g-C₃ N₄ ) suffers from fast photogenerated charge carrier combination, inferior light absorption and insufficient active sites. Herein, we developed a defect engineering approach which can simultaneously realize O dopant and N defects in the g-C₃ N₄ framework via an acid-assisted thermal treatment route. The modified g-C₃ N₄ demonstrated greatly enhanced photocatalytic H₂ activity with a H₂ evolution rate of 2.20 mmol ⋅ g^-1  ⋅ h^-1 , which is more than three times higher than that of bulk g-C₃ N₄ . The mechanism of the enhanced activity was investigated and proposed that the introduction of O dopants and N defects in the g-C₃ N₄ could optimize the electron structure, up-shift the conduction band, increase the surface area, and thus achieve more efficient separation of photogenerated carriers, stronger reduction ability and abundant active sites for photocatalytic H₂ evolution. Thus, defect engineering has been demonstrated to be a prospective strategy to modify the performance of g-C₃ N₄ for future photocatalytic energy generation.