Two-dimensional WS2-based nanosheets modified by Pt quantum dots for enhanced room-temperature NH3 sensing properties

As a typical two-dimensional (2D) layered transition metal dichalcogenides (TMDs), tungsten disulfide (WS 2 ) has been considered as a promising sensing material for room-temperature NH 3 detection. However, the bulk WS 2 -based room-temperature NH 3 sensors can hardly recover to its initial state after turning off gas . Although the recovery rate of bulk WS 2 was accelerated by thinning method, the response of few- or monolayer WS 2 nanosheets (NSs) to NH 3 was sharply decreased. Here, in premise of keeping fast recovery rate, few- or monolayer WS 2 NSs modified with Pt quantum dots (QDs) were prepared for room-temperature NH 3 detection, which exhibited significantly enhanced sensing properties with fast recovery speeds. Especially, the response of nanocomposite to 250 ppm NH 3 is nearly 10 times than that of WS 2 NSs, which could be attributed to the significantly decreased initial conductivity caused by electrons flowing from higher Fermi level of Pt QDs to that of WS 2 NSs and the higher catalytic activity. Furthermore, the Pt S bonds confirmed by XPS results could benefit electrons transfer between the interface. We hope that the 0D/2D heterostructure system in this work could provide a direction to improve sensing properties of 2D TMDs-based room-temperature sensors.