3D/2D Bi2S3/SnS2 heterostructures: superior charge separation and enhanced solar light-driven photocatalytic performance

Abstract

In promoting the application of green and sustainable solutions towards the photodegradation of organic dyes and toxic ions, it is urgent to fabricate semiconductor-based effective and stable photocatalysts. Constructing a heterojunction is the new way to accelerate the photoinduced charge separation to achieve enhanced photocatalytic activity. In this article, a novel 3D/2D heterostructure has been fabricated by a simple two-step solvothermal process. First of all, 3D Bi₂S₃ urchins were synthesized and after that 2D SnS₂ nanosheets were decorated on Bi₂S₃ urchins. The formation of Bi₂S₃ urchins was monitored at different reaction times and probed by scanning electron microscopy. Both theoretical calculations and experiments suggest that an epitaxial relationship was formed between the (211) plane of Bi₂S₃ and the (012) plane of SnS₂. A type-II band alignment between Bi₂S₃ and SnS₂ was established by theoretical investigation, which accelerated photoinduced charge separation and improved the photocatalytic activity of the Bi₂S₃/SnS₂ heterostructure. The surface area analysis of the Bi₂S₃/SnS₂ heterostructure with different SnS₂ loading was monitored and the increased surface area and the porous structure make the heterostructures more active than that of the pure one. Therefore, this 3D/2D heterostructure is found to be important as a new generation photocatalytic system.