Donor–acceptor covalent organic framework/g-C3N4 hybrids for efficient visible light photocatalytic H2 production

Abstract

Photocatalytic water splitting is a promising strategy for hydrogen energy production. However, it is still challenging to develop efficient and stable photocatalytic systems. Herein, a donor–acceptor type covalent organic framework (COF) was used to construct TBTA/g-C₃N₄ hybrids by the in situ condensation procedure of 2,4,6-triformylphloroglucinol (TP) and 4,4′-(benzo-1,2,5-thiadiazole-4,7-diyl)dianiline (BTDA) on g-C₃N₄. The obtained hybrids displayed higher photocatalytic activity than the individual components. The H₂ evolution rate of the hybrids achieves 11.73 mmol g⁻¹ h⁻¹ without a noble metal, which is competitive with cutting-edge g-C₃N₄ hybrid materials, and can be further increased to 26.04 mmol g⁻¹ h⁻¹ with Pt as a co-catalyst. A series of experimental methods combined with theoretical calculations have demonstrated that TBTA/g-C₃N₄ hybrids exhibit broad visible light absorptions and appropriate energy levels, resulting in an efficient charge separation upon irradiation and in turn excellent photocatalytic activity.