Rational and green synthesis of novel two-dimensional WS2/MoS2 heterojunction via direct exfoliation in ethanol-water targeting advanced visible-light-responsive photocatalytic performance

Two-dimensional transition metal dichalcogenides (2D TMDs) and their heterostructures have by far stimulated growing research interests in the field of optoelectronics and photocatalysis . In this regard, scalable fabrication of 2D TMDs at an environmentally-benign and cost-effective manner via liquid phase exfoliation is a particularly fascinating concept. Herein we report a facile and green strategy to produce few-layered WS 2 suspensions at a large scale by a direct exfoliation of commercial WS 2 powders in water-ethanol mixtures. In turn, by making full use of the features of 2D layered WS 2 , a novel 2D WS 2 /MoS 2 composite was constructed for the first time via an in-situ hydrothermal reaction to grow MoS 2 nanoflakes onto few-layered WS 2 basal planes. The as-obtained WS 2 /MoS 2 heterostructure was investigated for photocatalytic applications. Such a hybrid material demonstrated superior photocatalytic activity in the photocatalysis of organic dye molecules relative to that of pristine 2D WS 2 , MoS 2 and their physical mixtures. This enhancement was associated with the 2D WS 2 /MoS 2 heterostructuring effect. In addition, comparisons of the photocatalytic performances of our heterojunctions with those of recently reported 2D TMD-based hybrid materials manifested a significantly higher efficiency.