Pt and black phosphorus co-modified flower-like WS composites for fast NO gas detection at low temperature.

Incomplete recovery, baseline drift, and a long response time have been impeding the practical applications of transition metal dichalcogenide (TMD)-based gas sensors. Here, we report WS sensors with significantly improved gas recovery, rapid response, and negligible baseline drift by the incorporation of black phosphorus (BP) as well as the decoration of Pt to detect NO for the first time. Compared to bare WS, the BP-WS sensors show higher sensitivity, better repeatability, and more excellent selectivity towards NO at the optimal operating temperature of 50 °C. Furthermore, the optimized 30%BP-WS/Pt sensors exhibit a continuous enhancement in the recovery level and sensitivity with negligible baseline drift. The 30%BP-WS/Pt sensor also exhibits a shorter response time of 28 s than 49.5 s for its counterpart WS sensor towards 32 ppm NO. The enhanced sensing properties are primarily due to the combined effects of more adsorption sites provided by BP, the spill-over effect of Pt catalysis, and the WS/BP heterostructure. Therefore, the Pt-decorated 30%BP-WS sensor exhibits prominent gas-sensing properties of high gas sensitivity, a low detection limit of 100 ppb, good selectivity, and fast response. Our strategy provides a new route for designing and optimizing TMD-based gas sensors with excellent gas-sensing performance.