Electron, hole and radical competition mechanism of layered porous g-C3N4 for hydrogen generation and organic pollutant degradation

Halogen doping is an effective approach to regulate the electronic structure and improve photocatalytic properties of g-C 3 N 4 . Here, a salt-assisted approach was employed to prepare layered porous halogen-doped g-C 3 N 4 . The effects of halogen electronegativity and pore morphology were discussed. Highly electronegative F-doped g-C 3 N 4 with smaller pore size and higher surface area displayed the enhanced absorption property on reactants. The H 2 production rate decreased and the RhB degradation significantly increased with increasing the electronegativity of layered porous g-C 3 N 4 , which was significantly different from the conventional halogen-doped g-C 3 N 4 prepared with halogenated acid and monolayer g-C 3 N 4 . The decreased H 2 evolution can be ascribed to the strong adsorption property, and the strong interactions between halide ions and H + were difficult to be disassociated. Additionally, the RhB degradation performance of halogen-doped g-C 3 N 4 significantly increased with increasing the electronegativity. The most active species that dominated the RhB degradation of F-doped g-C 3 N 4 are leaved holes (h + ), which are totally different from that of the pristine g-C 3 N 4 and Cl/Br-doped g-C 3 N 4 (superoxide radicals,·O 2 – ). This work helps us to well understand the role and importance of electronegativity and pore morphology on the H 2 generation and RhB degradation properties of layered porous g-C 3 N 4 .