Ultralow-detection limit ammonia gas sensors at room temperature based on MWCNT/WO3 nanocomposite and effect of humidity

Characteristics of porous spherical LaFeO3 as ammonia gas sensing material

“…The response and recovery times are defined as the time required to take 90 % of the whole resistance change in the response and recovery processes, respectively. [34] The results revealed that both response and recovery times decreased with the increased working temperature from 300 to 375 o C, which could be assigned to the higher diffusion speed of NH3 gas at higher temperature. The transition resistance and the response of PS-LFO with different NH3 concentrations was presented in figure 6a and 6b, respectively.…”

“…The detail of the gas-sensing measuring system could be found elsewhere. [8,[33][34][35] 3. RESULTS AND DISCUSSION…”

“…The results showed that the response was linearly proportional to the NH3 concentrations with the sensitivity (or the slope of the linear line) was 0.0081 times/ppm. From linear relationship between response and NH3 gas concentration, the detection limit (DL) of the sensor was calculated via following equation [8,[33][34][35] DL = 3 × (rms/slope) (1) where rms is the root-mean-square deviation extrapolated from the fifth-order polynomial fit of the baseline (figure 6c); the slope is the sensitivity of gas sensor, which was extracted from the linear fit of response versus the NH3 concentration (figure 6b). The calculated DL was 0.32 ppm which implied a high potential of PS-LFO for the sub-ppm NH3 gas detection.…”

Recent progress in the fabrication of flexible materials for wearable sensors

“…fabricated nanocomposite-based NH 3 gas sensors that work at room temperature by compositing multi-walled carbon nanotubes (MWCNTs) and tungsten oxide (WO 3 ) nanobricks in different mass ratios. 87 He et al designed a bifiller of carbon nanotubes (CNTs) and graphene for filling flexible porous polydimethylsiloxane (CNTGR/PDMS) nanocomposites. The combination of 1D and 2D fillers was effective for good dispersion in the polymer matrix, and improved thermal stability of the nanocomposites was also achieved under the proper filler loading.…”

Conductive Polymer (Graphene/PPy)–BiPO4 Composite Applications in Humidity Sensors

“…Mallick et al enhanced the humidity-sensing properties of polyvinylidene fluoride titanium dioxide (PVDF-TiO 2 ) nanocomposites-based capacitive humidity sensors by modifying the film surface of the TiO 2 [14]. Duong et al fabricated composite multi-walled carbon nanotubes (MWCNTs) and tungsten oxide (WO 3 ) nanobricks at different mass ratios, which attained a high response with 95 wt.% of MWCNT/WO 3 nanocomposite [15]. Arularasu et al developed a PVDF/ZnO nanocomposite that was prepared as a humidity sensor through a Polymers 2021, 13, 2013 2 of 11 simple hydrothermal approach in which the PVDF/ZnO provided more water molecule adsorption and desorption across the humidity sensor surface compared to pure ZnO nanoparticles [16].…”