Semiconducting metal oxides (SMOXs) are used widely for gas sensors. However, the effect of ambient humidity on the baseline and sensitivity of the chemiresistors is still a largely unsolved problem, reducing sensor accuracy and causing complications for sensor calibrations. Presented here is a general strategy to overcome water‐sensitivity issues by coating SMOXs with a hydrophobic polymer separated by a metal–organic framework (MOF) layer that preserves the SMOX surface and serves a gas‐selective function. Sensor devices using these nanoparticles display near‐constant responses even when humidity is varied across a wide range [0–90 % relative humidity (RH)]. Furthermore, the sensor delivers notable performance below 20 % RH whereas other water‐resistance strategies typically fail. Selectivity enhancement and humidity‐independent sensitivity are concomitantly achieved using this approach. The reported tandem coating strategy is expected to be relevant for a wide range of SMOXs, leading to a new generation of gas sensors with excellent humidity‐resistant performance.

No abstract

Au-Doped mesoporous WO3 is prepared and it exhibited higher response to TMA gas.

Semiconducting metal oxides (SMOXs) are used widely for gas sensors. However, the effect of ambient humidity on the baseline and sensitivity of the chemiresistors is still a largely unsolved problem, reducing sensor accuracy and causing complications for sensor calibrations. Presented here is a general strategy to overcome water‐sensitivity issues by coating SMOXs with a hydrophobic polymer separated by a metal–organic framework (MOF) layer that preserves the SMOX surface and serves a gas‐selective function. Sensor devices using these nanoparticles display near‐constant responses even when humidity is varied across a wide range [0–90 % relative humidity (RH)]. Furthermore, the sensor delivers notable performance below 20 % RH whereas other water‐resistance strategies typically fail. Selectivity enhancement and humidity‐independent sensitivity are concomitantly achieved using this approach. The reported tandem coating strategy is expected to be relevant for a wide range of SMOXs, leading to a new generation of gas sensors with excellent humidity‐resistant performance.

No abstract

No abstract

No abstract

Surface modification by employing precious metals is one of the most effective ways to improve the gas-sensing performance of metal oxide semiconductors (MOS). Pure α-Fe2O3 nanoparticles and Pt-modified α-Fe2O3 nanoparticles were prepared sequentially using a rather simple hydrothermal synthesis and impregnation method. Compared with the original α-Fe2O3 nanomaterials, the Pt-α-Fe2O3 nanocomposite sensor shows a higher response value (Ra / Rg= 58.6) and a shorter response/recovery time (1 s / 168 s) to 100 ppm DMDS gas at 375 °C. In addition, it has better selectivity to dimethyl disulfide (DMDS) gas with the value of more than 9 times higher than the other target gases at 375 °C. This study indicates that the Pt-α-Fe2O3 nanoparticle sensor has good prospects and can be used as a low-cost and effective DMDS gas sensor.