Exploiting the capabilities of MoS2-WO3 heterojunction sensors for harmful NO2 gas detection at low temperature

Nitrogen dioxide (NO2) gas sensors have working at higher operating temperatures (200–400 °C), resulting in excessive energy consumption. Thus, there is a pressing need to develop novel nanomaterials or improve the prevailing functional nanomaterials to fascinatingly detect NO2 gas at lower temperatures. Herein, we present the operation of a MoS2-WO3 (MW) heterostructure at a notably reduced temperature of 50 °C. MoS2 nanoparticles (NPs) and WO3 nanoflowers (NFs) have fabricated by surfactant free, simple hydrothermal approach. The MW3 sensor with an atomic ratio of M:W (1:0.25) has demonstrated notably enhanced response (increasing from 0.4% for 1 ppm to 42.31% for 100 ppm), accompanied by a rapid 0.92 s response time and impressive baseline recovery in 10.74 s. The MW sensor at 50 °C has exhibited remarkable selectivity and stable performance toward NO2 gas. The exceptional sensitivity of porous MoS2-WO3 heterojunctions to NO2 arises from their distinct porous configuration and the combined impact of MoS2 NPs and WO3 NFs. This configuration offers a considerable specific surface area, complemented by the existence of oxygen vacancies within the sensing material. The impedance and X-ray photoelectron spectroscopy (XPS) have utilized to explore the plausible NO2 sensing mechanism of MW3 heterojunction sensor.