Functionalized Multiwalled Carbon Nanotubes for Highly Stable Room Temperature and Humidity-Tolerant Triethylamine Sensing

Phase-Engineered MoSe2/CeO2 Composites for Room-Temperature Gas Sensing with a Drastic Discrimination of NH3 and TEA Gases

“…A type-IV isotherm was observed for the BET surface area of the MoSe 2 and MoSe 2 /CeO 2 composites, and it indicated a mesoporous structure with a well-defined pore size distribution, as shown in Figure S7a,b and presented in Table S2. The isotherm shape signifies the occurrence of multilayer adsorption within the material, characteristic of mesoporous materials with interconnected pores. , A larger surface area of the composites allowed more gas molecules to interact with the material, thereby enhancing the sensing response. All the aforementioned results confirm that 1T- and 2H-MoSe 2 crystals were successfully synthesized through the controlled variation of solvothermal reaction conditions.…”

“…This exceptional discrimination of NH 3 and TEA is attributed to the unique interaction between the composite materials and the two gases, as well as the synergistic effects of the integration of MoSe 2 with CeO 2 , and it is consistent with previous observations. − The sensitivity of the composites was quantified by calculating the detection limit, defined as the lowest concentration of gas that can be reliably detected from the signal-to-noise ratio (S/N ≥ 3) obtained from the calibrated curves. The lower limit of detection (LOD) of the sensor devices was calculated from the eq : LOD = 3 σ / s where σ is the standard deviation of the response curve and s is the slope of the linear fit; s is also known as sensitivity. The values of s and the LOD for NH 3 (TEA) were found to be 5.5 (2.1) and 70 (160) ppb, respectively, which showed the excellent sensitivity of the composite sensors.…”

“…In particular, water exhibits high reactivity, with concentrations ranging from 6000 to 25,000 ppm at ambient conditions, that is accompanied by humidity fluctuations. These levels far exceed the levels of various trace gases. , Sensing tests were performed under both low- and high-humidity conditions. Figure S14a,b show the baseline variation and response of composite sensors to 2 ppm of NH 3 and TEA.…”

“…However, there was a noticeable decrease in the proportion of adsorbed oxygen ions at room temperature, from 23.3% (22.5%) to 17.5% (10.8%) after NH 3 (TEA) exposure (Figure f–i). These findings suggest that the surface-adsorbed oxygen plays an important role in the NH 3 and TEA-sensing reactions, consistent with previous reports. , Gas chromatography–mass spectrometry (GC–MS) was employed to identify the oxidation reactions of NH 3 and TEA, which are described by eqs and . These reactions are important for generating sensor signals.…”

Quasicrystal Nanosheet/α-Fe2O3 Heterostructure-Based Low Power NO2 Sensors: Experimental and DFT Studies

“…Response time (τ res ) defines the time required for the electrical resistance of the sensor to increase by 90% of its maximum value. The sensor’s recovery time (τ rec ) indicates the time required for the electrical resistance to return to 90% of its saturation value after removing the target gas from the environment chamber …”