Highly efficient photocatalytic hydrogen evolution from simulated seawater splitting by regulating internal electric fields in ultrathin carbon nitride with nonmetal dopant

Non-metal doping is an efficient way to modify the electronic structure of graphitic carbon nitride for boosting photocatalytic activity. Herein, a series of non-metal (P, B, and F) doped into g-C 3 N 4 with molten-salt synthesis. Compared with the g-C 3 N 4 -based materials, the PBFCN can separate and transfer the charge efficiently to facilitate more h + and e - to participate in the photocatalytic reaction, which is more favorable to the adsorption of H∗, thus promoting the photodegradation process of hydrogen production from seawater splitting. Among these photocatalysts, PBFCN demonstrated the most outstanding photocatalytic performance with the AQE of 13.4 % at 420 nm and outperformed reported carbon nitride-based photocatalysts. The hydrogen production rate of the PBFCN can reach 13.02 mmol h -1 g -1 , which was 7.7 times higher than that of MCN (1.69 mmol h -1 g -1 ). In addition, in the co-degradation experiment of bisphenol A, 496.21 μmol h -1 g -1 H 2 was generated, and the degradation rate of bisphenol A was close to 100 %. The rapid charge separation rate of gradually transferring electrons through the F→N→P→C→B stepwise pathway enables more electrons and holes to participate in the photocatalytic reaction, thus promoting the photodegradation process of hydrogen production from seawater. This research offers a novel approach for modulating electron density to regulate the electron transfer pathway and enhance photocatalytic activity via non-metal doping engineering. • The hydrogen production rate of the PBFCN was 7.7 times higher than that of the MCN. • PBFCN demonstrated the most outstanding photocatalytic performance with the AQE of 13.4 % at 420 nm. • The electrons transfer through the F.→N→P→C→B stepwise pass.