Two Dimension C₃N₄/MoS₂ Nanocomposites with Enhanced Photocatalytic Hydrogen Evolution under Visible Light Irradiation

Abstract

MoS₂-decorated C₃N₄ (C₃N₄/MoS₂) nanosheets hybrid photocatalysts were prepared by a simple sonication-impregnation method. Face-to-face lamellar heterojunctions were well established between two dimension (2D) C₃N₄ and MoS₂ nanosheets. The effects of MoS₂ content on the light absorption, charge transfer and photocatalytic activity of the hybrid samples were investigated. Characterization results show that MoS₂ nanosheets are well anchored on the face of C₃N₄ nanosheets and the composites have well dispersed layered morphology. After loading with MoS₂, the light absorption of composites was much improved, especially in visible-light region. The photocatalytic activities of C₃N₄/MoS₂ samples were evaluated based on the H₂ evolution under visible light irradiation (λ > 400 nm). When the loading amount of MoS₂ was increased to 5 wt%, the highest H₂ evolution rate (274 μmol·g^-1·h^-1) was obtained. Compared with samples obtained from direct impregnation method, sonication pretreatment is favorable for the formation of 2D layered heterojuctions and thus improve the photocatalytic activity. Slightly deactivation of C₃N₄/MoS₂ composites could be observed when recycled due to the mild photocorrosion of MoS₂. Based on the band alignments of C₃N₄ and MoS₂, a possible photocatalytic mechanism was discussed, where MoS₂ could efficiently promote the separation of the photogenerated carriers of C₃N₄.

Keywords

C₃N₄/MoS₂ / nanosheet / heterojunction / photocatalytic activity / H₂ evolution