A novel P-doped and NCDs loaded g-C3N4 with enhanced charges separation for photocatalytic hydrogen evolution

Graphite carbon nitride (g-C3N4) is a promising non-metal photocatalyst for photocatalytic hydrogen production, but its performance is still limited due to sluggish charges separation and low utilization of light. In this work, P-doped and N-doped carbon dots (NCDs) supported g-C3N4 were successfully prepared via hydrothermal and polymerization reactions. The sub-bandgap formed by P-doping enhances the utilization of visible light, and the high electron density of P sites is conducive to the trapping of holes. NCDs also improve light utilization and, more importantly, act as electron acceptors and transporters to promote electron transport. The built-in electric field formed by the synergy of P-doping and NCDs-loading greatly promotes the separation of charges. The PCN/NCDs showed a significantly improved hydrogen evolution activity of 3731 µmol h−1 g−1, which was 6.7 times that of pure carbon nitride (560 µmol h−1 g−1). This strategy may be generalized to the design of g-C3N4 -based photocatalysts, facilitating the separation of charges for enhanced catalytic activity.