The band structure and photocatalytic mechanism of MoS2-modified C3N4 photocatalysts with improved visible photocatalytic activity

Highlights: • A series of MoS₂/g-C₃N₄ photocatalyst were prepared by water exfoliation method. • The heterojunction enhanced the visible response and separated charge carriers. • The MoS₂/g-C₃N₄ exhibits enhanced visible photocatalytic activity. - Abstract: A series of MoS₂/g-C₃N₄ photocatalysts were prepared by modifying g-C₃N₄ with different concentration of MoS₂ via a water exfoliation method. The crystal structure, morphology, band structure of heterojunction, behaviors of charge carries and the redox ability were characterized by XRD, HR-TEM, absorption spectra, XPS, PL, cyclic voltammetry curves and transient photocurrent spectra. It is revealed that the introduction of MoS₂ on the surface of g-C₃N₄ nanosheets to form micro-heterojunction could enhance the visible response and separate photogenerated charge carriers effectively. Moreover, the ability of the photocatalyst for generating reactive oxygen species (ROS, such as O₂⁻ and OH) was also investigated. Therefore, MoS₂/g-C₃N₄ samples exhibit better photocatalytic performance for the photodegradation of HCHO than g-C₃N₄ and MoS₂ under visible irradiation.