Strategic review of gas sensing enhancement ways of 2D tungsten disulfide/selenide-based chemiresistive sensors: decoration and composite

Gas sensors that exhibit high sensitivity and possess astonishingly low detection limits are appealing for a wide range of practical applications, such as real-time environmental monitoring, exhaled breath diagnostics, security, medical diagnosis and the quality of food analysis. 2D tungsten disulfide/selenide is extensively investigated as a viable material for the fabrication of chemiresistive gas sensors due to its low price, high stability, high sensitivity, distinct electronics, and catalytic characteristics. To improve the performance parameters of the sensor, such as response, sensitivity, selectivity, and long-term stability, the sensing material layer of 2D-WS2 and WSe2 is modified by decorating it with different metal nanoparticles that form heterojunctions or composites of 2D material or semiconductor and carbon derivatives. In this article, we presented an in-depth review of current advancements in WS2 and WSe2-based chemiresistive gas sensors, with particular prominence on the role played by the various noble metal-decorated 2D materials and composites for high performance characteristics, including enhanced response, faster response and recovery times, reduced operating temperatures, and extremely low detection limits. We also talk about the difficulties that 2D-WS2 and WSe2 chemiresistive sensors face and their potential in the future.