Highly selective ammonia gas sensor at room temperature based on MoO3/MWCNT-9 nanocomposites

Herein, a resistive gas sensor based on Molybdenum tri oxide (MoO 3 )/ 9 % mass fraction of multi-walled carbon nanotubes (MWCNTs-9) nanocomposites was developed by hydrothermal method to detect NH 3 gas at room temperature. According to the findings, outstanding resistance change rate of 187.5 % was observed in MoO 3 /MWCNT-9 sensor when exposed to 100 ppm NH 3 at room temperature (25 °C). In contrast, 8.2 % response rate was recorded for pure MoO 3 sensor when exposed to same condition and the response value of newly fabricated sensor was improved by about 22.9 times to unalloyed MoO 3 . In addition, the nanocomposite sensor consisting of MoO 3 /MWCNT-9 had demonstrated excellent selectivity, repeatability, and a high level of sensitivity in detecting low concentrations of NH 3 at low temperature. During experiment when the sensor desorbed NH 3 gas at room temperature, a certain instantaneous voltage was applied, which greatly reduces the sensor’s resistance recovery time to 90 s. MWCNTs’s doping decreased the operating temperature of MoO 3 and showed good gas sensitivity at room temperature. Finally, the results reveal that MoO 3 /MWCNT-9 nanocomposite-based sensor can be fruitful in the field of NH 3 monitoring.