Aromatic Ring-Coordinated g-C3N4 Nanotubes for Enhanced Photocatalytic H2 Evolution
Chongze Cai, Huaiyu Lu, Cheng Cheng, Wengao Zeng, Xiangjiu Guan, Liuhao Mao, Tian Li, Jinwen Shi, Liejin Guo
Abstract
Abstract As one of the most promising metal-free photocatalysts for renewable H 2 evolution, graphitic carbon nitride (g-C 3 N 4 ) has attracted notable attention. Regulating its morphology and electronic structure is crucial for enhancing its performance. In this work, aromatic small molecules and melamine were hydrothermally cotreated to form a novel supramolecular precursor, which was subsequently calcined to obtain a π–π conjugated structure of g-C 3 N 4 photocatalyst. The introduction of benzene-ring structures expanded the conjugated system and promoted the excitation of π electrons, thereby broadening the light-absorption range of g-C 3 N 4 . The synergism of bromine and chlorine provided abundant active sites for g-C 3 N 4 , greatly promoted the migration of photogenerated charge carriers, and reduced the recombination probability, thus improving in photocatalytic performance. Therefore, the g-C 3 N 4 photocatalyst obtained from 2-bromo-5-chlorobenzoic acid-derived supramolecular precursor exhibited a visible-light ( λ ≥ 400 nm) photocatalytic H 2 evolution activity of 839.8 μmol/(h g), which was about three times that of the unmodified g-C 3 N 4 . This work offers a novel perspective for g-C 3 N 4 application in the field of photocatalysis and expands the utilization of aromatic small molecules in photocatalysts modification.