LPG Sensor Research Articles

Rapid Response and Quick Recovery LPG Sensor Fabricated Using Aqueous Sol–Gel Synthesized ZnO/Zn(OH)2 Hexagonal Nanoparticles

Rapid Response and Quick Recovery LPG Sensor Fabricated Using Aqueous Sol–Gel Synthesized ZnO/Zn(OH)2 Hexagonal Nanoparticles

Exploring the effect of zinc substitution in nanocrystalline nickel ferrite for enhanced supercapacitor and gas sensing applications

A hydrothermal method was employed to synthesize Zn-substituted nickel ferrite nanoparticles at an optimized reaction temperature of 175 °C. X-ray diffraction analysis of as-synthesized nanoparticles exhibited a cubic spinel structure, and the average crystallite size decreased from 41 nm to 31 nm with increasing dopant concentration. Morphological study confirmed the cubic shape of the prepared nanoparticles. Raman spectra exhibited five Raman active modes (A1g + Eg + 3T2g), which are attributed to ferrite. The dielectric constant decreased and became constant with increasing frequency, whereas the AC conductivity demonstrated an increasing trend. The oxidation state and elemental composition of Zn2+, Ni2+ and Fe3+ in Zn-doped NiFe2O4 were confirmed by XPS measurements. Mossbauer spectra were recorded to determine the oxidation state of the iron. The coercivity increased with increasing Zn concentration. The Day plot analysis confirmed the pseudo-single-domain nature of the as-synthesized nanoparticles. Pseudocapacitive behavior was observed for all samples, whereas a high Csp value was achieved for ZNF3 (598 F/g). The LPG sensor made out of the synthesized nanoparticles demonstrated faster response and recovery times of 13 and 31 s, respectively, when exposed to a concentration of 10 ppm.

Design and Development of Paper/ZnO–SnO2 Heterostructured Ultra-Fast TENG Based LPG Sensor

This work establishes a very simple and economical preparation of paper-based triboelectric nanogenerators for self-powered LPG sensing. Magnification in the output of TENG was achieved by ZnO/SnO2 synthesized by hydrothermal. This material has been thoroughly characterized through XRD, UV, FESEM, FTIR, and Nanozetasizer. The average crystallite size of the heterostructure was obtained as 17.59 nm. Bandgap of ZnO/SnO2 material was found as 3.49 eV. FESEM exhibits that present heterostructure material exhibits spherical nature with lots of voids on the film surface. From Nanozetasizer, the diameter of particles resides between the range 50–80 nm with an average particle size as 63.23 nm. The fabricated TENG generates a maximum output voltage of ∼75 volts which is more than the output of paper-based TENG. This TENG was used as a power source to operate a resistive LPG sensing film. The maximum response of 24 and minimum response-recovery times of 120–135 ms were observed, which makes this LPG sensing device ultra-fast.

Highly selective ppm level LPG sensors based on SnO2-ZnO nanocomposites operable at low temperature

The nanoscaled SnO2, ZnO and SnO2-ZnO nanocomposite powders were prepared by microwave aided ultrasonication technique by employing centrifuge for the collection of dried powder of the materials. The fabrication of thick films of the pure ZnO and SnO2-ZnO nanocomposite powders were made by simple screen printing technique. The crystallographic phases of the pure ZnO and SnO2 doped ZnO are hexagonal in nature. The average crystallite size of 0 (pure), 1, 3, 5, 7 and 9 wt% of SnO2 doped ZnO films was found to be 30.2, 30.3, 109.7, 37.9, 36.8 and 45.6 nm, respectively. The SEM micrographs depict the porous nature of the thick films. The EDS analysis reveals that the pure ZnO and SnO2 doped ZnO films are oxygen deficient and show a semiconducting nature. The symmetric I-V characteristics depict the ohmic and non-ohmic natures of the thick films. The electrical resistivity measurements indicate a negative temperature coefficient of resistance. The gravimetric analysis shows that the average thickness of the pure ZnO thick film is 28 µm. The LPG response versus doping concentration plot suggests that the (1 wt%) SnO2 doped ZnO thick film exhibits crucial response to 100 ppm LPG at 50 °C and 100 °C. Therefore, the SnO2 doped ZnO thick film can be applicable in the field of LPG sensing with rapid response and recovery.

High sensitivity LPG and H2 gas sensing behavior of MoS2/graphene hybrid sensors prepared by facile hydrothermal method

Here we design and fabricate the hybrid sensor based on molybdenum disulfide (MoS2)/graphene and evaluate the gas sensing permanence of various types of gases (LPG, ethanol, methanol, acetone, CO, and NO2) using a resistive gas sensor. The structural, morphological, elementary composition and textural properties of the sensors was systematically investigated through X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectra and N2 adsorption-desorption analysis. The fabricated hybrid sensor showed superior LPG gas sensing performance such as high sensitivity (12.2%), fast response (15 s) and recovery time (22 s) compared to H2 gas. Because of the high surface area of the hybrid sensor (78 m2/g) with a small pore size (35.45 nm), this outstanding performance is attributed to the combination of MoS2 spherical nanoparticles with 2D graphene layer providing a large active surface area that allows for additional absorption properties of gas molecules during chemical reaction. Studies of stability and selectivity further show that the fabricated MoS2/graphene hybrid sensor can be preferred for high-performance LPG sensor applications and home safety. It also deals with the process of present sensing.

Gigantic stimulation in response by solar irradiation in self-healable and self-powered LPG sensor based on triboelectric nanogenerator: Experimental and DFT computational study

The present paper reports the highest sensor response of Solar light induced, battery-less and self-healable LPG sensor powered by triboelectric nanogenerator. This work establishes the concept of waste to energy conversion and utilization of waste energy (finger tapping) for driving sensors for green and sustainable development. In this study synthesis of 2D PANI-PPY (2P) nanosheets by the polymerization and further its employment as PDMS/PANI-PPY (3P) based TENG is demonstrated. The fabricated TENG exhibits high output voltage of 142 volts and 80 µA current. 3P polymer nano-composite showed fast self-healing capability under 35 min. The assembled 3P based self-powered LPG sensor exhibits exceptional response and sensitivity under light illumination. The maximum sensor response of 94.67 (% response = 9367%) and the sensitivity 52.67 SR/vol% were found under 30 mW/cm2 visible light radiance, which illustrates that the developed material is extremely responsive and sensitive under light condition even at a very low concentration of LPG below LEL (2 vol%). The least recovery and response times of the material were measured to be 172 ms and 580 ms correspondingly. The theoretical analysis confirms that Cl-doped 2P was highly reactive and exhibited high negative potential sites to interact with the H+ ion of LPG.

Numerical Description of Jet and Duct Ventilation in Underground Garage after LPG Dispersion

Contamination of toxic and odorous gases emitted from stacks in buildings located in an urban environment are potential health hazards to citizens. A simulation using the computational fluid dynamic technique may provide detailed data on the flammable region and spatial dispersion of released gases. Concentrations or emissions associated with garage sources and garage-to-house migration rates are needed to estimate potential exposures and risk levels. Therefore, the aim of the study was to use an original mathematical model to predict the most accurate locations for LPG sensors in an underground garage for vehicles powered with LPG. First, the three-dimensional geometry of an underground garage under a multi-family building was reconstructed. Next, two types of ventilation, jet and duct, were considered, and different sources of LPG leakage were assumed. Then, the Ansys Fluent software was applied as a solver, and the same initial value of released LPG (5 kg) was assumed. As a simplification, and to avoid the simulation of choked outflow, the emission from a large area was adopted. The results showed stagnation areas for duct ventilation in which gas remained for both the jet and duct ventilation. Moreover, it was observed that the analyzed gas would gather in the depressions of the ground in the underground garage, for example in drain grates, which may create a hazardous zone for the users of the facility. Additionally, it was observed that for jet ventilation, turbulence appearance sometimes generated differentiated gas in an undesirable direction. The simulation also showed that for blowing ventilation around the garage, and for higher LPG leakage, a higher cloud of gas that increased probability of ignition and LPG explosion was formed. Meanwhile, for jet ventilation, a very low concentration of LPG in the garage was noticed. After 35 s, LPG concentration was lower than the upper explosive limit. Therefore, during the LPG leakage in an underground garage, jet ventilation was more efficient in decreasing LPG gas to the non-explosive values.

Visible light-induced, highly responsive, below lower explosive limit (LEL) LPG sensor based on hydrothermally synthesized barium hexaferrite nanorods

Here, the photo-enhanced behavior in LPG sensing of hydrothermally synthesized BaFe12O19 nanorods at room temperature under visible light radiation has been thoroughly inspected and reported. The sensing element is observed to be poorly responsive towards LPG in dark conditions at room temperature, while it reveals a good photo response in presence of visible light of 30 mW/cm2, and the visible light aids in improving the LPG sensing response up to a great extent at room temperature. Under the irradiation, the nanorods are found to detect the presence of LPG molecules of concentration as small as 0.5 vol% at the response and recovery times ~5.02 s and ~10.10 s respectively. The sensitivity of the visible-light induced material was evaluated ~41.27 sensor response/vol% with the maximum sensor response as high as 108, whereas, in dark, the same material showed a maximum response of ~6.64 with a sensitivity of merely 1.94 sensor response/vol%. The photo-generated carriers are suggested to be responsible for achieving a significant, stable, fast response in presence of LPG. This is the first ferrite based visible light-induced LPG sensor.

Smart Air Quality Monitoring and Sensing Device (SAQM Sensing Device)

Abstract: Air pollution is the biggest problem of every nation, whether it is developed or developing. Health problems have been growing at faster rate especially in urban areas of developing countries where industrialization and growing number of vehicles leads to release of lot of gaseous pollutants. Harmful effects of pollution include mild allergic reactions such as irritation of the throat, eyes and nose as well as some serious problems like bronchitis, heart diseases, pneumonia, lung and aggravated asthma. According to a survey, due to air pollution 50,000 to 100,000 premature deaths per year occur in the U.S. alone. LPG sensor is added in this system which is used mostly in houses. The system will show temperature and humidity. The system can be installed anywhere but mostly in industries and houses where gases are mostly to be found and gives an alert message when the system crosses threshold limit. The advantages of the detector, have a reliable stability, rapid response recovery and long-life features. It is affordable, userfriendly, low-cost and minimum-power requirement hardware which is appropriate for mobile measurement, as well as comprehensible data collection

WITHDRAWN: GIS-GPS based national air pollution monitoring system

In the last years, the amount of contamination in metropolitan areas has become unbreakable. As a result, the consistency deteriorates day by day. Poor air quality is described as the presence of toxic pollutants in the atmosphere, including solid objects, chemicals, or liquid droplets. Carbon dioxide CO2, nitrogen oxides NOx, sulphur dioxide SO2, and, Carbon monoxide CO are some of the most common air contaminants. This research is proposed the designing and mobile implementing, low cost monitoring system for air pollution using Arduino microcontroller and gas sensor like MQ2, MQ131, MQ135, MQ136, DHT22, measuring different harmful gases NOx, CO, SO2, CO2, NH4, smoke, Acetone, Alcohol, LPG, Toluene, temperature, humidity and GPS sensor “NEO-6M” that has the ability to track latitude and longitude location of air pollution concentration, and display the analysis result on ESRI maps to give the air pollution authorities the ability to monitor online the pollution behavior in the subject area, the system also save the result on SQL server DB. The data is classified using data mining algorithms, presenting the result on a map helps government, chemist, and physicians to analyze data in real time to simplify the decision making process and offer appropriate services to people. The proposed system uses J48 pruning tree classifier generated using cross validation of fold (10) with highest accuracy 100%, while IBK ≈ 99.67, Naïve bays ≈ 90.89, and SVM ≈ 81.4. we find that the common air quality for Baghdad (study area) is between (“good”, “Satisfactory”, and “Moderately polluted”) for 1835 collected records of air weather during (January and February 2021) time period.

Design and fabrication of quick responsive and highly sensitive LPG sensor using ZnO/SnO2 heterostructured film

Highly efficient LPG sensor working at room temperature was developed using a simple and cost-effective route. For this purpose, ZnO/SnO2 heterostructure was synthesized using the hydrothermal route and thin films of the material were prepared. X-ray Diffraction revealed all the crystal parameters including grain size, texture coefficient, dislocation densities, surface area which are necessary for a sensor. Also, particle size, zeta potential, and conductivity were observed using nanozetasizer. Heterojunctions at the surface of the film were viewed by Scanning electron microscopy. An optical band-gap of ∼3.85 eV was measured using UV–vis absorption spectrum. Further, the film was used as room ambient sensor for different concentrations of LPG. Among them, the best sensor response and sensitivity of 276.51 and 3.78 respectively were obtained for 2.0 vol% of LPG whereas minimum response and recovery time of 10 s and 15 s were obtained for 0.5 vol% of LPG.

Zn2SnO4 Modified ZnO Thick Film Resistors as LPG Sensor

Zn2SnO4 Modified ZnO Thick Film Resistors as LPG Sensor

Gas leakage detection and alerting system using Arduino Uno

The presence of hazardous LPG gas leakage in a domestic, work place, also, stored gases container gas which exhibits ideal characteristic is use. For that sake, an alarm unit is used to vibrate an alarm which is buzzer. Buzzer gives an audible sign of the presence of LPG volume. The sensors are widely used to detect essence of propane, iso-butane, LPG and even smoke. The sensor has an advantage to combine a sensitivity response time. If the LPG sensor senses gas leak from work place or home, sensor output goes to active low (logic-0) condition. Arduino UNO is used in the project; low signals are overlooked by the Arduino and gas leakage is been noticed by the Arduino. The Arduino UNO turns on the LCD and buzzer. It even turns on the GSM modem after that, it continues to send messages SMS to mobile number specifically mentioned in the program of the source code for alerting danger to the people.

Hierarchical flower-like Bi2SiO5/MWCNT nanocomposites for highly sensitive LPG sensor at room temperature

Designing and fabricating a heterojunction pn-type semiconductor can provide significant advantages for improving the gas sensing performance. Herein, a facile and cost-effective hydrothermal method is used to synthesize a flower-like Bi2SiO5/MWCNT-x (where MWCNT is x = 0–20 wt%) nanocomposites. Structural and morphological studies of as-prepared samples are carried out by using various characterization techniques viz., X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM). The enhanced LPG sensing performance at room temperature of flower-like Bi2SiO5/MWCNT nanocomposites is reported here. A systematic investigation of Bi2SiO5/MWCNT nanocomposites demonstrates that 10 wt% content Bi2SiO5/MWCNT nanocomposites exhibit excellent sensing properties: high sensitivity as well as selectivity towards LPG along with good reproducibility at room temperature. The Bi2SiO5/MWCNT-10 nanocomposite response towards 1500 ppm of LPG reached 77.71% at 30 °C (room temperature) and the response and recovery times are 21 s and 37 s respectively. The unique flower-like structure and synergetic effects are supposed to be responsible for improving the gas sensing performance of Bi2SiO5/MWCNT nanocomposites. Besides, the effect of relative humidity on the sensing performance of the Bi2SiO5/MWCNT nanocomposites is investigated. However, the as-prepared Bi2SiO5/MWCNT nanocomposites based sensor showed effective gas sensing performance at high humidity. The present sensor shows a high LPG response at room temperature and decreases with increase of temperature suggest its promising usage for the low-temperature region. This novel Bi2SiO5/MWCNT nanocomposite promises to provide an essential gas sensing material for the detection of LPG.

Development of high sensitivity LPG and NO2 gas sensor based ZnGa2O4/graphene nanoplates hybrid structure - A novel approach

The report is on high performance LPG gas sensor based ZnGa2O4/Graphene (ZGO/GR) structure by using facile hydrothermal approach. The heterostructure was characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), Raman and Brunauer-Emmett-Teller (BET) analysis. XRD results exposed that ZGO/GR is cubic phase with spinel structure. The fibers and platelets morphologies obtained were ZnGa2O4 and ZGO/GR sample, confirmed through FESEM and TEM analysis. Mesoporous with high porous nature and huge surface area (108 m2/g) of ZGO/GR hybrid samples was confirmed by N2 adsorption-desorption analysis. The resistive sensor was fabricated and the prepared sensors were evaluated towards LPG and NO2 gases with various concentrations at room temperature. The results deliver that the hybrid sensors have excellent sensing performance such as high sensitivity (52%), fast response (32 s) and recovery time (41 s) as well as high stability towards LPG gas. The obtained hybrid sensor is not only high sensitivity, it also high selectivity to LPG gas then other gas spices (NH3, ethanol, ammonia, CO and acetone). The improved mechanism is also proposed in detail.

Healable, highly sensitive LPG sensor based on Ni0.4Zn0.6Fe2O4 nanohybrid grown by autocombustion process

In this study, dual-layered self-healable LPG sensor which can successfully re-establish both of its structural and sensing properties after an external deformation occurred, has been reported. Here Ni0.4Zn0.6Fe2O4 (NZF) works as a highly sensitive LPG sensor which can detect LPG well below the lowest explosion limit (LEL) efficiently. The self-healing phenomenon has been achieved by urea-formaldehyde (U-F) microcapsules encapsulating NZF and linseed oil. The dual-layered self-healable sensing film is prepared by forming a lower layer using urea-formaldehyde (U-F) microcapsules capturing linseed oil and NZF, serving as healing layer, and an upper layer using NZF aiding sensing phenomenon. LPG sensing parameters like sensitivity, sensor response, recovery time and response time were investigated in case of both uncracked sample and healed sample to get a clear idea of how much sensing properties were recovered after healing took place. The minimum response and recovery times of the uncracked film corresponding to 0.5 vol.% LPG concentrations were found to be 28.08 s and 52.46 s respectively, whereas, the same after healing were as 34.39 s and 45.17 s respectively. After healing, ∼ 86.4 % sensitivity was restored. This is the first dual-layered microcapsule-based LPG sensor, which has healing property.

Internet of Things based Integrated Smart Home Automation System

Users often need to control and monitor activities inside the home remotely, for elderly parents, children, or pets. This paper presents a multifunctional, low-cost, and flexible system for smart home monitoring and control. The system is based on node-MCU ESP32 with Internet connectivity that allows remote device control. The system transmits sensor data to the Firebase database and can receive commands from the server, allowing automatic control. The android-based mobile app is designed for communication with the Firebase database and updating its values to monitor and control the various home appliances. For the demonstration of the feasibility of the system, various sensors like temperature, humidity, light, LPG (MQ-6), and motion sensors were integrated into a prototype of the home automation system. For the authentication and validation of the proposed system, the performance of the system is studied rigorously and is also evaluated.

The effect of annealing temperature thin films indium doped SnO2 to optics properties and material composition

This study aims to analyze the effect of annealing of tin oxide thin film doped with Indium. SnO2 thin film has many benefits as electronic devices, solar cells, LPG sensors, etc. Preparation of SnO2: In a thin film using a sol-gel spin coating technique that produces a thin film of high quality. The transmittance of the thin film experienced decreases with increasing ripening temperature with the transmittance of 96.6, 94.7, 89.6, 87.1, and 78.2% at a wavelength of 350 nm with annealing temperature increase, respectively. Thin-film absorbance has increased with higher heating temperatures i.e 3.01, 3.34, 3.41, 3.62, and 3.77, respectively. SnO2 thin film gap energy: In decreases due to increased ripening temperature at room temperature (35), 50, 100, 150, and 200 °C ie 3.65, 3.61, 3.59, 3.58, and 3.56 eV for direct energy gap and 3.96, 3.94, 3.93, 3.91, and 3.89 eV for indirect energy gap, respectively. The decreasing value of the gap energy makes the SnO2: In thin-film material faster in carrying current. The activation energy are decreased by increasing annealing temperature with value 2.91, 2.73, 2.15, 2.11 and 2.09 eV, respectively for increase temperature which makes electrons flow faster. Furthermore, thin-films composition with mass percentage Sn are 16.97% with atomic 2.77% and In are 1.46% with atomic 0.25%.

Sensing and structural characteristics of TiO2 thick film for LPG sensor

The sensing behavior and structural properties of cadmium sulfide (CdS) doped titanium dioxide (TiO2) thick film gas sensor were investigated and grown onto the alumina substrate. Microstructural properties are studied using X-Ray diffraction (XRD). The XRD measurement reveals that, the crystallites size of TiO2 was found ∼25.6 nm and ∼22.6 nm for sensor T1 (undoped TiO2) and T2 (CdS-TiO2) respectively. The response of the fabricated sensor T1 and T2 is measured varying the concentration of LPG (0–5000 ppm) in air ambient at 300 K. We observed that the sensor T2 has the highest response toward LPG (35) which is 2.5 times more than sensor S1 for the concentration of LPG (5000 ppm). The transient times of the fabricated sensor T2 are 130 sec and 350 sec.

Microwave-enhanced pyrolysis grown nanostructured SnO2 thin films for near room temperature LPG detection and the impedance analysis

Near room temperature LPG sensing ability of polycrystalline nanoparticulate SnO2 thin films prepared by pyrolysis of microwave irradiated (MwI) precursor is investigated without any post annealing process. This technique facilitates to produce homogeneous nano-structured thin films in just 15 min. The phase composition, morphology, and microstructure of the films obtained by pyrolysis of different duration MwI precursors are examined by XRD, FT-IR, TEM and HRTEM. The gas sensing properties of the films display a significant advancement in lowering LPG and CO2 sensing temperature in addition to sensitivity in comparison with the films from unirradiated precursor. The LPG sensors have shown considerable response down from 50 ppm at a lower operating temperature of 50 °C and for CO2 from ∼150 °C, along with high selectivity to NH3 and NO2. The 1 min irradiated films exhibit an excellent LPG response of −98.4 % in 500 ppm with a resistance ratio Ra/Rg of 78, whereas for 3 min irradiated, the CO2 response is +77.9 % in 500 ppm of gas. The photoluminescence and dielectric properties are investigated to elucidate the factors responsible for the enhancement in response of the microwave processed films. From the results of the impedance investigation, the role of interface states promoted by defects in microstructure on the gas sensing of SnO2 films is discussed.