Ethanol Gas Research Articles

Synthesis and characterization of ZnO and Au/ZnO thin films for ethanol gas sensing application

Synthesis and characterization of ZnO and Au/ZnO thin films for ethanol gas sensing application

The effect of synthesis techniques on the gas sensing properties of TiO2/SiC/CoFe2O4 nanocomposites as gas sensor

This study investigates the impact of two distinct methodologies on the structural, morphological, and gas sensing properties of TiO2/SiC/CoFe2O4 (TSC) nanocomposites determined using x-ray diffraction (XRD), scanning electron microscopy (SEM), LCR meter, and gas sensing unit respectively. The TiO2/SiC/CoFe2O4 nanocomposites were synthesized using chemical co-precipitation method (C-TSC) and the solid state method (G-TSC). The Scherrer formula was used to calculate the average grain size of C-TSC and G-TSC, which was estimated to be 8 ± 2 nm and 10 ± 2 nm, respectively. The formation of TSC nanocomposites was confirmed by XRD, SEM, and EDX analysis. The response (%) toward ethanol and NH3 gas was tested as a function of flow rate (ppm) and temperature from room temperature (28 °C) to 300 °C. The response (%) was observed to be increasing with increasing temperature and three intermediate temperatures were found. The response and recovery time were also measured with varying gas concentrations. The long-term stability of devices was tested up to 30 days and less variation in result was found, which confirms stability of sensor. The material synthesized using chemical co-precipitation method (C-TSC) shows better properties than G-TSC.

Preparation of flower-like hierarchical structure SnO2/g-C3N4 and its ethanol gas-sensitive properties

The flower-like hierarchical structured SnO2/g-C3N4 nanocomposites were successfully prepared by one-step hydrothermal method with high-temperature calcination. The structure and morphology of the synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption-desorption. The gas-sensitive performance of the pure SnO2 and SnO2/g-C3N4 sensors were investigated and compared towards ethanol gas. The results showed that the response of the SnO2/g-C3N4 composites to 100 ppm ethanol gas at 200 °C was 18.88, which was 2.09 times that of pure SnO2, with response and recovery time of 2 s and 13 s. In addition, the gas sensor has excellent selectivity for ethanol gas, good repeatability, and long-term stability. These gas-sensitive properties of the flower-like graded structure SnO2/g-C3N4 to ethanol gas are attributed to the materials which have unique graded structure and n-n heterojunction. KEY WORDS: Hierarchical structure, SnO2/g-C3N4, Gas sensing property Bull. Chem. Soc. Ethiop. 2025, 39(1), 141-152. DOI: https://dx.doi.org/10.4314/bcse.v39i1.12

Development of High-Performance Ethanol Gas Sensors Based on La2O3 Nanoparticles-Embedded Porous SnO2 Nanofibers.

Porous pure SnO2 nanofibers (NFs) and La2O3 nanoparticles (NPs)-embedded porous SnO2 NFs were successfully synthesized via electrospinning followed by calcination. These materials were systematically evaluated as gas-sensing elements in metal-oxide-semiconductor (MOS) sensors. The La2O3 NPs embedded in porous SnO2 NFs demonstrated superior gas-sensing performance compared to pure SnO2 NFs. Specifically, the incorporation of La2O3 resulted in a 12-fold enhancement in gas-sensing response towards ethanol, significantly improving both sensitivity and selectivity by tuning the carrier concentration and modifying oxygen deficiencies and chemisorbed oxygen levels. Thus, La2O3 NPs embedded in SnO2 NFs present a promising strategy for the development of high-performance ethanol gas sensors.

Passive RFID integrated sensors based on ZnO/CuO/RGO and SnO2/CuS/RGO nanomaterials are used for CO2 and ethanol detection in fruit and vegetable storage and transportation

This article proposes and designs a passive RFID integrated dual parameter gas sensor that can respond to ethanol and carbon dioxide gases at room temperature. Firstly, nanocomposite sensitive materials were prepared by hydrothermal method, and their microstructure and elemental composition were analyzed through TEM, SEM, XRD, XPS and UPS characterization tests. The dual frequency gas sensing antenna was designed and optimized using HFSS software, and a high-precision engraving mechanism was used to prepare the sensor model. Finally, two different gas sensitive materials were deposited on the corresponding positions of the symmetric structure of the sensing antenna, and the different gas concentration changes were converted into amplitude and frequency changes at different frequency points of the sensing antenna. The test results showed that the sensor operates within the range of carbon dioxide concentration of 600 ppm–1600 ppm, with an amplitude change of 10.3 dB and a sensitivity of 0.009 dB/ppm. The sensitivity of the sensor is 0.29 MHz/ppm when operating stably within the ethanol concentration range of 200 ppm–2800 ppm. Compared with traditional gas sensors, passive RFID dual parameter gas sensors have the advantages of selective response to carbon dioxide and ethanol gases in mixed gas environments, fast response speed, strong anti-interference to interfering gases, and strong temperature adaptability. It has a good application prospect transportation, agricultural greenhouses, and food testing.

Correlation Between Structural, Electrical, and Optical Properties of ZnO:In for Ethanol Gas Sensing Application

Correlation Between Structural, Electrical, and Optical Properties of ZnO:In for Ethanol Gas Sensing Application

Enhanced ethanol gas sensing performance of Ag/SnO2 composites

A simple hydrothermal method was adopted to synthesize rectangular block-shaped SnO2 nanomaterials loaded with different amounts of Ag. The structural composition, morphology and chemical state of the nanomaterials were systematically investigated using XRD, SEM, TEM and XPS analysis. The gas sensing performance to ethanol was comprehensively evaluated by testing key parameters including gas response, optimal operating temperature, response-recovery time, and selectivity. The result demonstrates that the Ag/SnO2 composite, compared to pure SnO2, exhibits enhanced efficiency in detecting ethanol. The gas sensor fabricated by the sample Ag/SnO2-2 had a response of up to 80 for 200 ppm ethanol at 300℃. Moreover, the response time (reduced from 52 s to 29 s) and the selectivity were significantly improved. The superior gas sensing performance of Ag/SnO2 is attributed to the generation of highly active sites from Ag ion loading, accelerated electron transfer processes, and modulation of Schottky heterojunctions. In summary, this work demonstrates an effective strategy to improve the gas sensing performance of SnO2-based sensors by Ag loading.

ZnSnO3 micro-polyhedrons with oxygen defects derived from rubidium incorporation for enhanced ethanol detection

Detecting ethanol in ambient air is of great significance in protection of ecological environment, human health and social economy. Herein, a strategy is adopted to substantially improve the gas sensing performance of the ZnSnO3 micro-polyhedrons through rubidium (Rb) doping. In this study, a series of ZnSnO3 micro-polyhedrons with different amounts of Rb doping were successfully synthesized through a typical hydrothermal procedure and air sintering. The sensor based on 2 mol% Rb-doped ZnSnO3 exhibits high response value (108) and rapid response/recover speed (20/8 s) to 100 ppm ethanol at 260 °C, as well as outstanding repeatability and stability. Combining theoretical calculations and various characterization techniques, the improved sensing property of the 2 mol% Rb-doped ZnSnO3 to ethanol gas can be ascribed to the large specific surface area and the abundant surface defects induced by Rb incorporation. We believe that this study opens up a new perspective for developing efficient and high-performance ethanol gas sensor.

Fe2O3-Co3O4 nanocomposite gas sensor for ethanol sensing studies

This study focused on pristine Fe2O3, pristine Co3O4, and Fe2O3-Co3O4 composite using the Pechini sol-gel method for ethanol gas sensing applications. Advanced characterization techniques were used to analyze the phase, morphology, and composition of the synthesized materials. Gas sensors were then fabricated and used for ethanol gas sensing at different temperatures. The results indicated that Fe2O3-Co3O4 composite gas sensor crystallized at 600 °C, had higher response compared to both pristine Fe2O3 and pristine Co3O4 gas sensors. The composite sensor manifested a high response of 26.2–100 ppm ethanol at 250 °C, while maximum responses of pristine Co3O4 gas sensor was only 4.4 at 200 °C and that of pristine Fe2O3 sensor was 11.4 at 300 °C. The boosted sensing performance of the composite sensor was related to the formation of p-n heterojunctions between Co3O4 and Fe2O3 in composite sensor, the formation of dangling bonds at interfaces, and high intrinsic ethanol sensing properties of Fe2O3.

Continuous Microreactor‐Based Synthesis of SnO2 Nanoparticles for Sensor Applications

Tin oxide nanoparticles are well‐established materials with a wide range of applications, including optoelectronic devices and solid‐state gas sensors. Conventional synthesis methods of these systems are often based on batch processes. In this study, we compare batch and continuous synthesis methods for tin dioxide nanoparticles using precipitation and sol‐gel processes. For the continuous processes we applied the so called microjet reactor method. The nanoparticles were characterized by TEM, elemental analysis and XRD and exhibited particle sizes of 1.7‐3.0 nm and crystallite sizes of 1.7‐2.3 nm, consisting of tetragonal (P42/mnm) and orthorhombic (Pbcn) phases. We have evaluated different post‐synthesis purification methods to remove impurities such as chlorides and carbon‐hydrogen species. Each purification method exhibited unique advantages and side effects, providing insight into selecting the most appropriate method for specific applications. We also demonstrated the potential of these SnO2 nanoparticles as ethanol gas sensing materials and compared their performance with a commercial sensor.

Highly selective ethanol vapour sensing materials for a new generation of gas sensors based on molecularly imprinted polymers

A simple gas sensor consisting of a molecularly imprinted polymer-carbon nanotube composite cast onto a screen-printed electrode has been developed with extremely high selectivity for ethanol vapour over methanol vapour. Ethanol gas sensors typically display selectivity for ethanol over methanol in the range 2–4 times, while the mean ratio of ethanol to methanol response observed with the described device was 672. This selectivity was achieved under ambient conditions. Additionally, the molecularly imprinted polymer was produced using reagents previously applied in the development of a device selective for methanol, with only the template being changed. This demonstrates the versatility of molecular imprinting and provides a foundation for their greater integration into future gas sensors.

In-doped ZnO films deposited by modified SILAR method for enhanced ethanol gas sensor application

The rapid and skillful detection of toxic gases is a crucial requirement for the advancement of gas sensors. In this study, we fabricated undoped and In-doped (1 %, 3 %, and 5 % by weight) ZnO films using a two-step modified SILAR deposition technique. The ethanol gas sensing properties of both undoped and In-doped ZnO films were examined across a range of operating temperatures (from room temperature, 27 °C–200 °C) and concentrations (1 ppm–50 ppm). Of all the films, those doped with 5 % Indium exhibited the most stable, reproducible, and highest response, achieving 86.27 % at 50 ppm ethanol at an operating temperature of 100 °C. Compared to the undoped ZnO films, all Indium-doped ZnO films demonstrated significantly shorter response times (17 s) and recovery times (19 s). The response of all the deposited films to various gases such as acetone, methanol, toluene, xylene, and formaldehyde was lower than their response to ethanol. The mechanism behind the enhanced sensing characteristics of the Indium-doped ZnO films is explored. Additionally, the impact of humidity on sensor performance was investigated. This study reveals that 5 % In-doped ZnO films hold great potential as materials for ethanol gas sensing applications.

Tunable sensing performance of BiSb monolayer for ethanol induced by strain: A DFT study

Developing tunable gas sensors is pivotal for advancing the embodied perception of robots. In this study, first-principles calculations explore the adjustable sensing capabilities of BiSb monolayers towards ethanol gas under external biaxial and uniaxial strain. The results indicate a reduction in adsorption energy with increasing tensile strain in both biaxial and b-directional uniaxial conditions. Furthermore, strain effectively modulates the electronic structure of the adsorption system. Additionally, computed recovery times suggest that BiSb monolayers face significant challenges in ethanol gas desorption without strain, making them unsuitable for gas sensing under normal conditions. However, under strain, BiSb monolayers demonstrate potential as gas sensors for ethanol detection. These findings introduce novel avenues for enhancing the sensing performance of BiSb monolayers and underscore their prospective application as reversible sensors for ethanol detection.

Development and prototyping of a concentrated ethanol gas monitoring system based on the MQ-3 sensor using the KAVi machine calibrator for environmental safety

This research outlines the development of a device for measuring concentrated ethanol gas concentrations using the MQ-3 sensor. The device is engineered utilizing an Arduino Uno microcontroller and an LCD as the output interface. The MQ-3 sensor has demonstrated optimal sensitivity and a linear response to ethanol gas. The range of ethanol gas concentrations tested, from 10% to 70%, was selected to match the capabilities of the KAVi machine in generating ethanol gas. The testing process of the sensor was conducted to generate data that were subsequently calibrated to ensure measurement accuracy. Validation results indicate that the MQ-3 sensor can measure ethanol gas concentrations with high accuracy and good linearity within this range. However, discrepancies between the sensor measurements and the calibrator values were observed and need attention. The development of this device provides improvements in the accuracy and linearity of the MQ-3 sensor compared to previous studies. It is important to note that the KAVi machine has limitations in producing ethanol gas concentrations above 70%, which should be considered in the practical applications of this device. Overall, this device shows great potential in applications for monitoring ethanol gas concentrations, with a note to consider the limitations of the ethanol gas production process from the KAVi machine for more optimal results.

Fast Responsive and Highly Sensitive Ethanol Gas Sensors Designed by Agar‐Laponite Hybrid Hydrogels

AbstractLaponite, a synthetic nanosilicate clay and agar, a natural polysaccharide, both imbibe large amount of water and form into hydrogels. Various physical and chemical stimuli elicit the hydrogel response, which has been applied in designing diverse sensors and biomedical systems. In this work, we exploit the change in hydrogel's ionic conductivity due to volatile organic compounds (VOCs) (e. g. ethanol) interaction with the surfaces of Laponite‐Agar hybrid hydrogel films. Gas sensing studies are carried out on silicon (Si) and flexible polyethylene terephthalate (PET) substrates by monitoring the resistance changes. Pristine Laponite hydrogel has shown increase in resistance as it interacted with the ethanol, whereas pure agar and Laponite‐Agar have shown decrease in resistance. Moreover, Laponite‐Agar gel films have exhibited high sensitivity, fast response (4 s) and recovery time (15 s) with lowest detection limit of 6 ppm. Selectivity test carried shows high ethanol sensing response and exhibited very good reproducibility. Observed responses and sensing mechanism are discussed based on changes in ionic conduction resulted due to interacting ethanol with the gel surface network structure. Present study paves the way for understanding and designing low cost, soft and flexible hydrogel gas sensors.

A novel peony shaped ZnO and its excellent ethanol gas-sensing performance

In order to improve the gas-sensing performance of ZnO, a novel peony shaped ZnO stacked with nanosheets were prepared using hydrothermal method, and the obtained ZnO was characterized and tested for gas sensitivity. The results showed that the particle distribution of the peony shaped ZnO was uniform, with a particle size of about 0.8 μm. The gas-sensing response test results show that the peony shaped ZnO has excellent selectivity to ethanol gas. When the concentration of ethanol gas is 100 ppm, the gas-sensing response of the peony shaped ZnO to ethanol gas reaches 17.4, and the response time and recovery time are 8 s and 12 s, respectively. Even at an ethanol gas concentration of 2 ppm, the gas-sensing response of the peony shaped ZnO to ethanol gas can reach 2.1. Compared to existing literature reports, the peony shaped ZnO prepared in this paper has better gas-sensing performance. This study will provide data support and theoretical reference for the development of high-performance gas sensors.

Fast identification of flammable chemicals based on broad learning system

Fast identification of flammable chemicals is essential for industrial production and laboratory safety. With the continuous advancement of sensor technology, data-driven methods have become a promising tool for gas identification. However, these methods face problems such as insufficient feature learning, unstable prediction of the single classifier, and overfitting caused by insufficient data. In this work, a kernel-based BLS (KBLS) method is proposed, in which the kernel matrix is used to calculate the sample distances and map the feature nodes to the kernel space to reduce the uncertainty. In addition, KBLS uses a pseudo-inverse method to solve the weights, which greatly avoids the risk of overfitting while improves computational efficiency. To avoid the errors caused by a single classifier for specific gas samples, KBLS is used as the weak learner and combined with the AdaBoost algorithm to form an Ada-KBLS classifier to achieve fast and accurate gas identification. In the Ada-KBLS model, the sample weights obtained by the previous weak learners are used to train the following weak learners. This method improves the classification performance by paying attention to difficult and misclassified samples and integrating the classification results of multiple weak learners. In addition, a dataset containing four flammable gases is used to verify the effectiveness of the Ada-KBLS model. The initial stage of all response data is divided into different time windows as the input of the model to test the fast gas identification ability of the method. The Ada-KBLS achieves an average classification accuracy of 98.4 % in the 4 s time window, the best among all models, and the training time is only 6.22 s. The result represents a 0.4 % improvement over the second-best model, KBLS, and a 4.5 % increase compared to the 93.9 % accuracy achieved by Random Forest (RF). In addition, the precision, recall, and F1-score of ethanol gas classification reach high values of 100 %. The experimental results demonstrate the robustness and effectiveness of the proposed method in handling the task of fast detection of flammable gases, thus promoting the application of BLS and ensemble learning in gas identification.

Modification of chromium oxide nanofibers by polyoxometalate electron acceptor doping for enhancement of ethanol gas detectability

Herein, we introduced polyoxometalates (POMs) as electron acceptors into a typical gas sensitive material Cr2O3 for the first time. A series of Cr2O3/PW12 composite gas sensors were fabricated. The sensing properties to ethanol vapor were studied. The optimized Cr2O3/5%PW12 sensor exhibited a response of 7.65 to 100 ppm ethanol, which is much higher than pure Cr2O3. The improvement can be attributed to the synergistic effect between the two components. As an electron acceptor, PW12 promotes carrier migration between PW12 and Cr2O3, thereby improving the gas sensing performance of Cr2O3. This work promotes the practical application of polyoxometalate in sensing field.

Vertically aligned 2D tin sulfide (SnS) nanoplates for selective detection of ethanol gas at room temperature

Abstract Detection of ethanol gas quickly and efficiently at room temperature is crucial for ensuring environmental, human as well as industrial safety. In this work, we have demonstrated a chemiresistive room temperature ethanol gas sensor based on vertically aligned tin sulfide (SnS) nanoplates. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) analysis have revealed the formation of orthorhombic, vertically aligned SnS nanoplates with high specific surface area. The sensor has been fabricated by depositing the SnS powder sample on ITO sheets using electrophoretic deposition (EPD), followed by the deposition of silver (Ag) electrodes using the thermal evaporation technique. The sensor obtained has exhibited a response value (R g/R a) of 17.4–400 ppm ethanol gas concentration, a quick response, and a recovery time of 12.4 s and 20.2 s at room temperature. The sensor has demonstrated long-term stability of 15 min, impressive selectivity, and remarkable repeatability across three successive test cycles of ethanol gas at 400 ppm. Based on the experimental sensing results, a plausible mechanism has been proposed for the sensor. The sensing response of SnS-based sensor at room temperature expands its potential for innovative applications across industries, marking a significant advancement in sensing technology.

Effect of doping level on the photoconduction and chemiresistive ethanol gas sensing of lanthanum-doped CuO films

Undoped and lanthanum (La)-doped copper oxide (CuO) thin films were prepared by the nebulizer spray pyrolysis technique. The X-ray diffraction analysis revealed that the effective doping of lanthanum does not alter the monoclinic crystalline structure of copper oxide thin films. Raman spectra confirmed the crystalline quality of undoped and La-incorporated CuO films. From, scanning electron micrograph images, the La-doped CuO films exhibit spherical particles. Energy dispersive X-ray analysis confirmed the existence of copper, lanthanum and oxygen elements. The doping of La-substituted CuO films showed a minimum bandgap when compared to undoped CuO film. The oxidation states of Cu 2p, La 3d and O 1s elements were observed. The electrical resistivity of the films was considerably decreased due to the doping of La ions in CuO matrix. The photoluminescence spectra show that the doping of La ions increases the defect states and shows increased intensity. The time resolved photoluminescence analysis revealed that an extended carrier lifetime was observed for the La-doped films. The La-doped CuO sensors achieved a superior gas sensing performance at room temperature and exhibited quick response and recovery times, suggesting that the sensor has the potential for the detection of harmful volatile gases in real-world applications. The photoconductive investigation revealed that the La-doped CuO films exhibited higher charge-transporting properties and increased light-harvesting ability. This study sheds light on designing gas sensors working under ambient conditions and photosensors for optoelectronic devices.