Tin bisulfide nanoplates anchored onto flower-like bismuth tungstate nanosheets for enhancement in the photocatalytic degradation of organic pollutant

The development of efficient heterojunctions through a simple and facile method is an effective way to enhance the photocatalytic performance of bismuth-based oxide semiconductors for industrial applications. Here, the novel flower-like type II SnS2/Bi2WO6 heterostructure consisting of bismuth tungstate (Bi2WO6) nanosheets and tin bisulfide (SnS2) nanoplates was successfully designed and synthesized. The crystal structure, composition, morphology, and photoelectric properties of the heterostructure were systematically characterized. In addition, the photocatalytic activity of SnS2/Bi2WO6 was analyzed and compared with Bi2WO6 or SnS2 alone or physical mixture of SnS2 and Bi2WO6. 2%SnS2/Bi2WO6 presents a 3.1 times greater degradation rate constant (0.0065 min-1) than that of Bi2WO6 (0.0021 min-1) under low visible light irradiation (5.3 mW·cm-2, a 44 W LED), while SnS2 alone exhibits no photocatalytic effect toward glyphosate. Furthermore, 2%SnS2/Bi2WO6 maintains 93% of its original photocatalytic activity even after four cycles. The possible photocatalytic degradation pathway of glyphosate and photocatalytic mechanism are also proposed. The excellent photocatalytic performance of SnS2/Bi2WO6 is attributed to the decoration of SnS2 nanoplates on the surface of Bi2WO6, appropriate (113)/(020) ratio, increased visible-light absorption, and effective separation of photoinduced carriers. This paper reports a new methodology that can act as a reference basis to design and develop visible-light responsive photocatalysts with outstanding photocatalytic performance for carbon dioxide reduction, water splitting, and pollutant degradation.