Metal loaded nano-carbon gas sensor array for pollutant detection ^*

Abstract

Many research works report a sensitive detection of a wide variety of gas species. However, their in-lab detection is usually performed by using single gases and, therefore, selectivity often remains an unsolved issue. This paper reports a four-sensor array employing different nano-carbon sensitive layers (bare graphene, SnO2@Graphene, WO3@Graphene, and Au@CNTs). The different gas-sensitive films were characterised via several techniques such as FESEM, TEM, and Raman. First, an extensive study was performed to detect isolated NO2, CO2, and NH3 molecules, unravelling the sensing mechanism at the operating temperatures applied. Besides, the effect of the ambient moisture was also evaluated. Afterwards, a model for target gas identification and concentration prediction was developed. Indeed, the sensor array was used in mixtures of NO2 and CO2 for studying the cross-sensitivity and developing a calibration model. As a result, the NO2 detection with different background levels of CO2 was achieved with an R2 of 0.987 and an RMSE of about 22 ppb.

Defect-Selective Functionalization of 2D-WS2 Nanofilms with Pt Nanoparticles for Enhanced Room-Temperature NO2 Gas Sensing

“…It reacts with other chemical compounds present in the ambient atmosphere, contributing to the formation of acid rain and ozone, thereby exacerbating air pollution concerns. Furthermore, the United States Environmental Protection Agency underscores the deleterious effects of long-term exposure to NO 2 , emphasizing that even at low concentrations, as low as several hundred parts per billion (ppb), it can induce eye and lung irritation; therefore, it is regulated with an exposure limit of 53 ppb. , Therefore, the reliable and highly responsive detection of trace amounts of NO 2 is crucial for environmental monitoring and health protection.…”

Selective gas detection of titania nanoparticles via impedance spectroscopy and capacitive measurement

“…In general capacitive sensors are fabricated in a vertical configuration where between the two electrodes a dielectric layer is incorporated which acts as a sensing layer [3]. Upon gas exposure, the capacitive change results from the effective dielectric (ɛ eff ) variation of sensing material, and its associated void region is used as an indicative mark for the detection of trace amounts of gases [14][15][16][17]. Resonance under gas exposure occurs at a particular frequency where the device showed maximum capacitive change than that of the air ambient.…”

“…Resonance under gas exposure occurs at a particular frequency where the device showed maximum capacitive change than that of the air ambient. Therefore, the sensitivity of the device toward specific gas or selectivity can be enhanced by finding resonant peaks over the tested frequency range [14,17].…”

Octahedral Molybdenum Iodide Clusters Supported on Graphene for Resistive and Optical Gas Sensing

“…Additionally, high specificity may result in limited reversibility of the gas–solid interactions, which compromises response repeatability. Finally, the last mainly used strategy is the decoration of graphene with metal or MOX nanoparticles. , With that, it is possible to significantly increase the sensitivity and tune the selectivity to some extent. However, these MOX nanoparticles usually need moderate or high operating temperatures for activating their sensing properties.…”