One-step synthesis of C quantum dots/C doped g-C₃N₄ photocatalysts for visible-light-driven H₂ production from water splitting

Graphitic carbon nitride (g-C₃N₄) is gaining more and more attentions as a promising metal-free photocatalyst for H₂ production. Nevertheless, from the perspective of practical applications, the photocatalytic performance over g-C₃N₄ in visible-light region needs a further improvement. In this work, C doping and C quantum dots (QDs) are co-integrated in g-C₃N₄ by a one-step thermal polymerization method to obtain an advanced C QDs/C doped g-C₃N₄ photocatalyst. The synergistic effects of C doping and C QDs modification promote the photocatalytic activity of g-C₃N₄ significantly. The optimal C QDs/C doped g-C₃N₄ exhibits a significant improvement on visible-light-driven photocatalytic hydrogen production (205 μmol g⁻¹ h⁻¹) with an apparent quantum yield (AQE) at 420 nm reaching 1.24%, which is approximately nine-fold enhancement than that of pristine g-C₃N₄. The increased photocatalytic activity mainly benefits from the enhanced visible light absorption and carrier separation efficiency. This study may open a new perspective for the design and fabrication of C-modified g-C₃N₄ for photocatalytic hydrogen production.