In situ ion-exchange synthesis of SnS2/g-C3N4 nanosheets heterojunction for enhancing photocatalytic activity

Abstract

In this paper, free standing graphitic carbon nitride (g-C₃N₄) nanosheets have been synthesized by mixed solvents (water/IPA = 2/1) liquid phase exfoliation, and a series of SnS₂/g-C₃N₄ heterojunctions with different contents of SnS₂ have been prepared via a simple ion-exchange process. Exfoliated g-C₃N₄ presents a two-dimension sheet-like structure with the thickness of 2.8 nm and small SnS₂ nanoparticles with diameter of 5–10 nm are well anchored on the surface of g-C₃N₄ nanosheets, which was proved by transmission electron microscopy (TEM) and atomic force microscope (AFM). The 4.0-SnS₂/g-C₃N₄ sample shows the highest photocurrent density of 13.66 μA cm⁻² at 0.8 V, which is about 1.5 time of the g-C₃N₄ nanosheets and 2 times of the bulk g-C₃N₄, respectively. Photocatalytic measurement also demonstrated that constructing heterojunction of SnS₂/g-C₃N₄ can improve the photocatalytic efficiency as compared to pure g-C₃N₄ and g-C₃N₄ nanosheets. The highly effective photoelectrochemical and photocatalytic activities of SnS₂/g-C₃N₄ heterojunctions are attributed to the efficient separation of photogenerated hole–electron pairs. This work may provide a novel concept for the rational design of high performance g-C₃N₄-based photocatalysts.