Chemiresistive room temperature H2S gas sensor based on MoO3 nanobelts decorated with MnO2 nanoparticles

In this work, we develop ultrafast detection and reversible H2S gas sensor at room temperature (RT, 23 ℃). The optimized MoO3/MnO2 (MM-10) sensor exhibits remarkable sensitivity to H2S with a response of 32.51–100 ppm H2S at RT, which is approximately 21.82 times higher than that of the MoO3 sensor. Further, the MM-10 sensor demonstrates a fast response of 5.71–1000 ppb H2S with response/recovery times of 40/42 s at RT. More surprisingly, the theoretical limit of the MM-10 sensor for detecting H2S gas is as low as 4.58 ppb at RT, which addresses the limitation of binary heterojunction-based sensors in detecting ppb-level H2S gas at RT. After 49 days, the MM-10 sensor still demonstrates reliable stability, ensuring the long-term detection to ppb-level H2S at RT in practical applications. Notably, as the relative humidity increases from 30 % to 90 %, the response only decreases by about 17 %, indicating an excellent shielding ability against water molecules. Additionally, it is found that 1 % relative humidity change has a comparable effect on MM-10 sensor as approximately 5.58 ppb H2S gas. The significant enhancement mechanism on the sensing surface in the context of H2S/MoO3/MnO2 interaction is also thoroughly discussed. [Display omitted] •An ultralow detection limit and room temperature H2S gas sensor is demonstrated.•The MM-10 sensor possesses swift response/recovery speed and high response at RT.•The MM-10 sensor has an excellent shielding ability against water molecules.•The sensing procedure of H2S/MoO3/MnO2 interaction is deeply discussed under experimental conditions.