Detection Of Ethanol Vapor Research Articles

Characteristic of graphene-based thick film gas sensor for ethanol and acetone vapor detection at room temperature

<p>Ethanol and acetone are volatile organic compound gases widely used in food processing. Health problems such as irritation of the eyes, nose, and throat can affect human health if exposed to these gases. Two graphene gas sensors were fabricated using a screen-printing technique onto a glass substrate to compare their performance to the acetone and ethanol vapors at room temperature. The graphene paste was prepared by mixing 95 wt.% of the binder with 5 wt.% of graphene nanoflakes. A silver paste was used asthe interdigitated electrode of the gas sensor and becamethe first layer of the gas sensor. The silver paste was deposited on the glass substrate using a screen-printing technique and fired at 150°C for 15 minutes. Next, the graphene paste was depositedonto the interdigitated electrode using a screen-printing technique and becamethe second layer of the gas sensor. The graphene was annealed at 200°C for 30 minutes. Both graphene gas sensors responded well to ethanol and acetone vapor with an n-typed gas sensor at room temperature. As a comparison, the graphene gas sensor showed better characteristics in terms of response and recovery characteristicsto ethanol vapor than acetone vapor at room temperature. The response and response time of the graphene-based thick film gas sensor to ethanol were approximately 21.89 and 24.08, respectively.</p>

Enhanced, selective, and room temperature detection of ethanol vapor by RF-sputtered TiO2 thin films

Enhanced, selective, and room temperature detection of ethanol vapor by RF-sputtered TiO2 thin films

Improved Ethanol Sensing Performance of α-MnO2 Nanorods at Room Temperature Enabled through PPy Embedding.

Ethanol is a colorless, highly flammable, volatile organic compound and is a biomarker for fatty liver diseases. So, high-performance and reliable ethanol sensors are the need of the day for biomedical and environmental monitoring applications and drunken driving detection. In this work, we have reported a polypyrrole (PPy)-embedded α-MnO2 nanorod (NR)-based chemiresistive sensor for the selective detection of trace ethanol vapor at room temperature (25 °C). PPy-embedded α-MnO2 NR nanocomposites (MP25, MP50, and MP100) were synthesized by in situ chemical oxidative polymerization of pyrrole followed by mixing of α-MnO2 NR having different weight ratios. The prepared nanocomposites were characterized by various sophisticated instruments such as XRD, FTIR, Raman spectroscopy, BET, FESEM, TEM, EDX, UV-vis spectroscopy, and current-voltage (I-V) measurement. The as-prepared sensor, namely, PPy-embedded α-MnO2 nanorod (MP50), shows the highest response to ethanol vapor with a detection lower limit of 1 ppm at room temperature with rapid response (∼2.39 s) and recovery (∼37.08 s) times associated with at least 60 days stability, excellent selectivity, good repeatability, and reproducibility. The formation of a p-n heterojunction and transfer of charge carriers between PPy and MnO2 nanoparticles are attributed to the enhancement of sensing performance. Thus, the prepared sensor could be potentially applicable to detect ethanol content in alcoholic beverages, diagnose liver disease from exhale breath analysis, and drunken driving detection.

Fabrication and characterization of a bifunctional zinc oxide/multiwalled carbon nanotube/ poly(3,4-ethylenedioxythiophene): Polystyrene sulfonate composite thin film

Hybrid thin film sensors based on semiconductor oxides and carbon nanostructures are promising materials to improve the sensing, thermomechanical and optical properties. In this study, a thin film based on a composite from ZnO nanoparticles, milled multiwalled carbon nanotubes, and conducting polymer was fabricated. The layer was spray-coated to the surface of amorphous polyethylene terephthalate substrate. The hybrid layer and components have been systematically characterized by transmission and scanning electron microscopy, dynamic light scattering and the optical absorption spectrum was observed by ultraviolet-visible spectroscopy. The change in glass transition temperature was measured by dynamic mechanical analysis. Gas sensing tests reveal that the ZnO/multiwalled carbon nanotube/ poly(3,4-ethylenedioxythiophene): polystyrene sulfonate film on amorphous polyethylene terephthalate has remarkably enhanced performance compared to the same layer on indium tin oxide /polyethylene terephthalate. It could detect ethanol vapor in a wide concentration range with good response, fast recovery, and repeatability at room temperature. The layer was also tested as an ultraviolet photodetector, showing a promising signal. These features indicate the composite usability in further sensor applications.

High sensitivity ethanol vapor sensor based on a nematic liquid crystal film embedded optical fiber Sagnac interferometer

Interferometric optical fiber sensors have become the preferred choice for ethanol vapor detection because of their high sensitivity and figure of merit. However, the response time of interferometric fiber optic ethanol vapor sensors is very long. To address this issue, we experimentally investigated an ethanol vapor sensor based on a nematic liquid crystal (NLC) film embedded optical fiber Sagnac interferometer. The high birefringent NLC film, which worked as the sensing media of ethanol vapor for its absorption of ethanol vapor, was penetrated into the Sagnac ring to generate the spectral interference. The results showed that the measurement sensitivity of ethanol gas concentration reached 2.22 pm ppm−1. The detection range was about 1210 ppm–10 000 ppm. Most importantly, the response time of the proposed sensor is only 15 s. The designed sensor, which showed the advantages of fast response, high sensitivity, and stability, could be a competitive candidate for ethanol vapor sensing.

An investigation of the influence of nanofibers morphology on the performance of QCM-based ethanol vapor sensor utilizing polyvinylpyrrolidone nanofibers active layer

Quartz crystal microbalances (QCMs) coated by polyvinylpyrrolidone (PVP) nanofibers with controlled morphology have been made for ethanol vapor detection. We used electrospinning to deposit PVP nanofibers of different morphologies (spherical-beaded, spindle-beaded, and pure nanofiber) on a QCM surface to study the effect on sensor performance. BET characterization revealed that the spherical-beaded nanofiber had the highest BET-specific surface area than the other morphologies, which improves the QCM sensor sensitivity, limit of quantification (LOQ), limit of detection (LOD), and sensor response. QCM coated with spherical-beaded nanofiber showed improved sensitivity of 2.632 Hz/ppm, lower LOD and LOQ of 0.018 ppm and 0.061 ppm, and better response compared to those coated with spindle-beaded and pure nanofiber. Based on adsorption isotherm models, Freundlich adsorption isotherm was found to be the most suitable for describing ethanol vapor adsorption on the sensor. The high sensitivity of the sensor to ethanol vapor was attributed to hydrogen bonding interactions between the sensor and the ethanol molecules. This study shows that the QCM-based sensor performance can be improved by modifying the morphology of nanofibrous coating layer.

Investigation of Annealing Process Effects on the Response and Stability of Sprayed Co2SnO4 Film under Ethanol Vapor

The ethanol (C2H5OH) vapor detection properties of a layer of cubic spinel cobalt stannate as-prepared Co2SnO4 (denoted as CTOas), elaborated by a low-cost spray pyrolysis method, were investigated before and after an annealing process. The response of layers under ethanol vapors of different concentrations exhibited a stable behavior in a dry atmosphere at the optimum working temperatures. The elaborated nanomaterials were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), direct current measurement (DC) and impedance spectroscopy techniques (AC). After the annealing process of pure CTOas, an n-type to p-type conductivity switch was observed and attributed to Co3O4 apparition in the Co2SnO4 structure. The layer’s ethanol response increased and became more stable after annealing. The stability was measured over a period of three months. DC and AC investigations allowed us to propose a detection mechanism involving grain boundary regions in a Co2SnO4/Co3O4 composite obtained after annealing (denoted as CTOann). According to its stable and receivable sensing response, the Co2SnO4/Co3O4 composite could be considered as a promising novel sensitive layer for ethanol gas sensors.

Enhanced Room-Temperature Ethanol Detection by Quasi 2D Nanosheets of an Exfoliated Polymeric Graphitized Carbon Nitride Composite-Based Patterned Sensor.

A novel room-temperature gas sensor composed of polymeric graphitic carbon nitride composite was fabricated and used for the detection of ethanol vapor under ambient conditions. Polymeric carbon nitride (PCN) microstructures composed of fluffy nanosheets were synthesized via a thermal polycondensation mechanism using melamine as the precursor, followed by vigorous chemical exfoliation. These sheet-like microstructures were employed as active materials in the form of composites, along with carbon paste consisting of graphite nanoplatelets and carbon black. The active sensing layer was fabricated on a PET sheet and assembled on an interdigitated gold electrode. The as-fabricated sensor exhibited excellent sensing efficiency (>100% response at 10 ppm) along with high selectivity and stability. In particular, for ultralow concentrations such as 1 ppm (>10% response), this resistive-based sensor exhibited a swift response time provided under ambient conditions. The exfoliated PCN composite sensor was found to be working with appreciable efficiency at moderate relative humidity (%) with the least fluctuation in response signals also demonstrating long-term stability for 30 days with consistent response signals.

Hierarchical nanodisk synthesis of α-MoO3 nanomaterials for highly selective and sensitive ethanol vapour detection

In this work, a facile metal oxide-based VOCs sensor was fabricated for ethanol detection at room temperature. The crystallite size was analysed to be 44 nm by Debye-Scherrer formula and bandgap was calculated to be 3.56 eV using tauc plot relation. The response of α-MoO3 sensor was about 24, 44, 66, 86, and 92 % towards the 100, 200, 300, 400 and 500 ppm concentrations of ethanol, respectively. The response and recovery time of sensor were 10 s and 4 s, respectively for 500 ppm concentrations of ethanol at ambient conditions. The response of the sensor was slightly decreased by increasing the relative humidity (RH). About 2 % decrement in response of the sensor was observed after 15 days under 97 % RH.

Novel insights into the unique intrinsic sensing essences of 2D tin chalcogenides for ethanol: From hexagonal SnS2 to orthorhombic SnS

Introducing orthorhombic SnS phase into two-dimensional (2D) hexagonal SnS2 crystal to form in-plane heterojunctions has become a promising approach to facilitate the sensitivity of SnS2 towards trace gases. However, its surface sensitization mechanism remains to be exploited in addition to the heterointerface effect. Hence, to dig into it, we explored the surface adsorption of SnS and SnS2 from unique surface electron configurations by combing experimental, computational and bionic approaches. Taking ethanol vapor as the target gas, orthorhombic SnS shows rapid detection of trace ethanol with a sub-ppm level at room temperature (RT). In contrast, hexagonal SnS2 is more suitable for detecting ethanol vapor with much higher concentrations (above 50 ppm). First-principles calculations and porcupine quill models further reveal that unlike the inactive symmetry of electrons on SnS2 surface, the rotational symmetry breaking of the stereochemically-active SnS surface leads to the oriented rearrangement of its surface electrons, which greatly facilitates the adsorption of trace ethanol molecules on SnS. On these basis, we renew the design concept of SnS–SnS2 in-plane heterostructures. This work reveals the structure-property relationship between the crystalline structures and gas-sensitive characteristics of 2D tin chalcogenides from a brand-new perspective, and helps the design and research of novel lateral heterostructures.

Design and development of SnO decorated BaTiO3 heterostructure device platform for ethanol vapor detection

Design and development of SnO decorated BaTiO3 heterostructure device platform for ethanol vapor detection

Amperometric Detection of Ethanol Vapors by Screen Printed Electrodes Modified by Paper Crowns Soaked with Room Temperature Ionic Liquids

AbstractA convenient assembly recently proposed for screen printed gold electrodes (SPEs) suitable for measurements in gaseous samples is here tested for the analysis of the ethanol content in alcoholic drinks. This assembly involves the use of a circular crown of filter paper, soaked in the room temperature ionic liquid (RTIL) 1‐butyl‐3‐methylimidazolium hydrogen sulfate, which is simply placed upon a disposable screen printed cell, so as to contact the outer edge of the gold disc working electrode, as well as peripheral counter and reference electrodes. The electrical contact between the paper crown soaked in RTIL and the SPE electrode is assured by a gasket and all components are installed in a polylactic acid holder. This assembly provides a portable and disposable electrochemical platform, assembled by the easy immobilization onto a porous and inexpensive supporting material such as paper of a RTIL characterized by profitable electrical conductivity and negligible vapor pressure. The electroanalytical performance of this device was assayed for the flow injection analysis of the ethanol concentration in some real samples of wine and beer and the results obtained are compared with the alcoholic degree reported in the relevant bottle‐labels, thus highlighting a substantially satisfactory agreement. Repeatable sharp peaks (RSD=6–8 %) were detected for ethanol over a wide linear range (1–20 % v/v in water) and a detection and quantitation limit of 0.55 % v/v and 1.60 % v/v were inferred for a signal‐to‐noise ratio of 3 and 10, respectively.

Gas Sensor Based on ZnO Nanostructured Film for the Detection of Ethanol Vapor

In this paper, the ZnO<La> target was synthesized by the solid-state reaction method and a nanostructured thin film was deposited by the RF (radio frequency) magnetron sputtering method on a Multi-Sensor-Platform. The obtained ZnO<La> nanostructured film was investigated as the sensing material. Energy-Dispersive X-ray (EDX) analysis indicated the existence of La in the synthesized ZnO<La> material. Scanning Electron Microscope (SEM) images of the film showed the grain sizes in the range of 20–40 nm. Sensor performance characteristics such as a dynamic response, response and recovery times, and ethanol detection range were investigated at 50–300 °C. A sensitivity was observed at extremely low concentrations of ethanol (0.7 ppm). The minimum response and recovery times of the sensor corresponding to 675 ppm ethanol vapor concentration at 250 °C were found to be 14 s and 61 s, respectively. The sensor showed a high response, good selectivity, fast response/recovery behavior, excellent repeatability toward ethanol vapor, and low sensitivity toward humidity. These characteristics enable the use of a ZnO<La> based sensor for ethanol detecting applications.

Broadband Dielectric Spectroscopic Detection of Ethanol: A Side-by-Side Comparison of ZnO and HKUST-1 MOFs as Sensing Media

The most common gas sensors are based on chemically induced changes in electrical resistivity and necessarily involve making imperfect electrical contacts to the sensing materials, which introduce errors into the measurements. We leverage thermal- and chemical-induced changes in microwave propagation characteristics (i.e., S-parameters) to compare ZnO and surface-anchored metal–organic-framework (HKUST-1 MOF) thin films as sensing materials for detecting ethanol vapor, a typical volatile organic compound (VOC), at low temperatures. We show that the microwave propagation technique can detect ethanol at relatively low temperatures (<100 °C), and afford new mechanistic insights that are inaccessible with the traditional dc-resistance-based measurements. In addition, the metrological technique avoids the inimical measurand distortions due to parasitic electrical effects inherent in the conductometric volatile organic compound detection.

The detection of ethanol vapors based on a p-type gas sensor fabricated from heterojunction MoS2–NiCo2O4

In this paper, the hydrothermally synthesized nanocomposites (MoS2–NiCo2O4) were exploited to detect various volatile organic compounds (VOCs). Some characterizations such as XRD, Raman, N2 adsorption-desorption isotherms, SEM, EDS and XPS were explored to identify the structure and morphology of these materials. More importantly, different sensors were designed from synthesized nanocomposites to see their sensing performance to various VOCs. Among these sensors, the sensor of MNCO-6 (6 mL MoS2 decorated with NiCo2O4) detected the highest response to 100 ppm ethanol while an insignificant response to other VOCs was noticed; moreover, good repeatability and response/recovery time (15/6 s), the response (1.63) to 0.1 ppm ethanol was also distinguished.

Highly sensitive and low detection limit of ethanol gas sensor based on CeO2 nanodot-decorated ZnSnO3 hollow microspheres

In order to achieve high response, excellent selectivity and stable detection of ethanol vapor, CeO2 nanodot-decorated ZnSnO3 hollow microspheres with heterostructures that could meet the requirements of ethanol detection were obtained through a convenient hydrothermal method. The prepared uniform nanodot-decorated hollow microspheres were observed by SEM and TEM, it is noticeable that CeO2 nanodots of about 10 nm were uniformly anchored on the surface of ZnSnO3 hollow microspheres with a diameter of 0.8–1.4 μm. Compared with the pure ZnSnO3, the 15% CeO2/ZnSnO3 hollow microspheres exhibited higher response (219.2) to 100 ppm ethanol, superior selectivity (ethanol) and rapid response recovery. In addition, a scientific and effective method was used to calculate the ultra-low theoretical gas detection limit (11.3 ppb) of the CeO2 nanodot-decorated ZnSnO3 hollow microspheres. The outstanding gas sensing properties were attributed to the existence of large amounts of dissociative oxygen and the n-n heterojunction between ZnSnO3 and CeO2. Meanwhile, our work confirmed that CeO2 nanodot-decorated ZnSnO3 hollow microspheres have satisfied the application needs of ethanol detection.

Nitrogen incorporated zinc oxide thin film for efficient ethanol detection

Zinc oxide which is a n-type semiconducting metal oxide (SMO) has been a promising material for detecting ethanol vapor. However, pure ZnO based ethanol sensors often suffer from high working temperature, cross sensitivity towards methanol and poor stability against humidity. Here in we report improving the ethanol sensing characteristics of ZnO thin films by substitutional nitrogen doping. Ethanol sensing characteristics of the N-ZnO thin film has been compared with pure ZnO sensor over a wide range of temperature and relative humidity conditions. The N-ZnO sensor exhibits significantly large ethanol sensing response at a lower operating temperature (~99% at 225 °C vs ~81% at 250 °C for ZnO), faster response time (12 s vs 33 s for ZnO), long term stability, improved resilience against humidity and selectivity towards ethanol over other VOCs. The experimental observations have been supplemented by estimating the adsorption energies of ethanol on ZnO and N-ZnO surface using density functional theory (DFT) calculations. We discuss that the microscopic origin of improved ethanol sensing of N-ZnO is related to the facile adsorption of ethanol molecules on the oxide surface which is promoted by modification of electronic properties of ZnO by the nitrogen dopant atoms.

The Effect of Current Density on the Properties of Porous Silicon Gas Sensor for Ethanol and Methanol Vapour Detection

In this paper, Gas sensors for ethanol and methanol were created utilizing porous silicon (PSi).n-type silicon was employed for all PSi samples, photo-electrochemical etching technique (PECE) was used to prepare porous surface. The intensity of the three etchings current densities was 12, 24 and 30 mA / cm2, with 40% hydrofluoric acid concentration (HF) and a time of etching 10 minutes. Porous silicon (100) has been strictly studied by the structure and formation of surface bonding of the PSi layer; the structural properties, morphological characteristics, pore diameter, and roughness were described using X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). All PSi samples were applied as a sensor for ethanol and methanol at room temperature. The results showed that the best sensitivity of PSi was to ethanol gas compared to methane under the same used conditions at etching current density 30mA/cm2, reaching about 1.809 at a concentration of 500 ppm. From these results, the PSi layers act as high-quality, low-cost gas sensors. It can be used as a replacement for expensive material that is used as gas sensors, which operate at low temperatures, including room temperature. The interest in this material is due to study the effect of extremely high surface to volume ratio (increasing surface area), and easy manufactured and compatibility with modern silicon microelectronics manufacturing technologies.

Design of high-sensitivity ethanol sensor based on Pr-doped SnO2 hollow beaded tubular nanostructure

Pr-doped SnO2 hollow beaded tubular nanostructure was synthesized by electrospinning technique, accompanied by using carbon spheres as sacrificial templates. The crystalline phase, morphology, microstructure, and element composition of the samples were explored and analyzed. The gas sensitivity test results show that Pr-doped SnO2 sensor exhibits high response value, excellent selectivity and rapid response-recovery ability to ethanol at 200 °C. The sensor can effectively detect ethanol vapor as low as 2 ppm. Response/recovery time to 100 ppm ethanol are about 12 s/8 s, respectively. The possible enhancement mechanism caused by the synergistic effect of the unique nanostructure, the carbon templates, and Pr dopant are discussed. The research may provide a better design of ethanol sensors.

Gas Sensor Based on Surface Enhanced Raman Scattering.

In order to address problems of safety and identification in gas detection, an optical detection method based on surface enhanced Raman scattering (SERS) was studied to detect ethanol vapor. A SERS device of silver nanoparticles modified polyvinylpyrrolidone (PVP) was realized by freeze-drying method. This SERS device was placed in a micro transparent cavity in order to inject ethanol vapor of 4% and obtain Raman signals by confocal Raman spectrometer. We compared different types of SERS devices and found that the modification of polyvinylpyrrolidone improves adsorption of ethanol molecules on surfaces of silver nanoparticle, and finally we provide the mechanism by theory and experiment. Finite Difference Time Domain(FDTD) simulation shows that single layer close-packed Ag nanoparticles have strong local electric field in a wide spectral range. In this study, we provide a case for safety and fingerprint recognition of ethanol vapor at room temperature and atmospheric pressure.