A NOVEL ROUTE FOR THE FORMATION OF GAS SENSORS

The rapid development of conductive polymers shows great potential in temperature chemical gas detection as their electrical conductivity is often changed upon spotlight to oxidative or reductive gas molecules at room temperature. However, the relatively low conductivity and high affinity toward volatile organic compounds and water molecules always exhibit low sensitivity, poor stability and gas selectivity, which hinder their practical gas sensor applications. In addition, inorganic sensitive materials show totally different advantages in gas sensors like high sensitivity, fast response to low concentration analytes, high area and versatile surface chemistry, which could harmonize the conducting polymers in terms of the sensing individuality. It seems to be a good option to combine inorganic sensitive materials with polymers for gas detection for the synergistic effects which has attracted extensive interests in gas sensing applications. In this appraisal the recapitulation of recent development in polymer inorganic nanocomposites-based gas sensors. The roles of inorganic nanomaterials in improving the gas sensing performances of conducting polymers are introduced and therefore the progress of conducting polymer inorganic nanocomposites including metal oxides, metal, carbon (carbon nanotube, graphene) and ternary composites are obtainable. Finally, conclusion and perspective within the field of gas sensors incorporating conducting polymer inorganic nanocomposites are summarized. Keywords: Gas sensor, conducting polymer, polymer-inorganic nanocomposites; conducting organic polymers nanostructure, synergistic effect, polypyrrole (PPY), polyaniline (PANI).

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Metal-oxide based ammonia gas sensors: A review

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681210999200718005402 ◽

2020 ◽

Vol 10 ◽

Author(s):

Priya Gupta ◽

Savita Maurya ◽

Narendra Kumar Pandey ◽

Vernica Verma

Keyword(s):

Metal Oxide ◽

Metal Oxides ◽

Gas Sensor ◽

Gas Sensors ◽

Review Paper ◽

Gas Sensing ◽

Gas Sensitivity ◽

Ammonia Gas ◽

Ammonia Sensing ◽

Ammonia Gas Sensors

: This review paper encompasses a study of metal-oxide and their composite based gas sensors used for the detection of ammonia (NH3) gas. Metal-oxide has come into view as an encouraging choice in the gas sensor industry. This review paper focuses on the ammonia sensing principle of the metal oxides. It also includes various approaches adopted for increasing the gas sensitivity of metal-oxide sensors. Increasing the sensitivity of the ammonia gas sensor includes size effects and doping by metal or other metal oxides which will change the microstructure and morphology of the metal oxides. Different parameters that affect the performances like sensitivity, stability, and selectivity of gas sensors are discussed in this paper. Performances of the most operated metal oxides with strengths and limitations in ammonia gas sensing application are reviewed. The challenges for the development of high sensitive and selective ammonia gas sensor are also discussed.

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Optimization of a Low-Power Chemoresistive Gas Sensor: Predictive Thermal Modelling and Mechanical Failure Analysis

Sensors ◽

10.3390/s21030783 ◽

2021 ◽

Vol 21 (3) ◽

pp. 783 ◽

Cited By ~ 1

Author(s):

Andrea Gaiardo ◽

David Novel ◽

Elia Scattolo ◽

Michele Crivellari ◽

Antonino Picciotto ◽

...

Keyword(s):

Low Power ◽

Failure Analysis ◽

Gas Sensors ◽

High Performance ◽

Gas Sensing ◽

Mechanical Failure ◽

Sensing Applications ◽

Theoretical Approaches ◽

Sensing Material ◽

Silicon Bulk

The substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane sizes were developed using the microfabrication process. The performance of these devices was evaluated to predict their thermal and mechanical behaviors by using both experimental and theoretical approaches. Finally, a statistical method was employed to cross-correlate the thermal predictive model and the mechanical failure analysis, aiming at microheater design optimization for gas-sensing applications.

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Advanced development of metal oxide nanomaterials for H2 gas sensing applications

Materials Advances ◽

10.1039/d0ma00880j ◽

2021 ◽

Author(s):

Yushu Shi ◽

Huiyan Xu ◽

Tongyao Liu ◽

Shah Zeb ◽

Yong Nie ◽

...

Keyword(s):

Metal Oxide ◽

Gas Sensors ◽

Gas Sensing ◽

The Past ◽

Sensing Applications ◽

The Future ◽

Metal Oxide Nanomaterials ◽

Nanomaterials Synthesis ◽

Advanced Development

The scheme of the structure of this review includes an introduction from the metal oxide nanomaterials’ synthesis to application in H2 gas sensors—a vision from the past to the future.

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Double Notched Long-Period Fiber Grating Characterization for CO2 Gas Sensing Applications †

Sensors ◽

10.3390/s18103206 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3206 ◽

Cited By ~ 2

Author(s):

Hsiang-Chang Hsu ◽

Tso-Sheng Hsieh ◽

Tzu-Hsuan Huang ◽

Liren Tsai ◽

Chia-Chin Chiang

Keyword(s):

Gas Sensor ◽

Transmission Loss ◽

Gas Sensing ◽

Fiber Grating ◽

Co2 Gas ◽

Long Period Fiber Grating ◽

Long Period ◽

Sensing Applications ◽

Co2 Gas Sensor ◽

Period Fiber Grating

In this study, we applied a double-sided inductively coupled plasma (ICP) process to nanostructure long-period fiber grating (LPFG) in order to fabricate a double-notched LPFG (DNLPFG) sensor with a double-sided surface corrugated periodic grating. Using the sol-gel method, we also added thymol blue and ZnO to form a gas sensing layer, thus producing a DNLPFG CO2 gas sensor. The resulting sensor is the first double-sided etching sensor used to measure CO2. The experimental results showed that as the CO2 concentration increased, the transmission loss increased, and that the smaller the fiber diameter, the greater the sensitivity and the greater the change in transmission loss. When the diameter of the fiber was 32 μm (and the period was 570 μm) and the perfusion rate of CO2 gas was 15%, the maximum loss variation of up to 3.881 dB was achieved, while the sensitivity was 0.2146 dB/% and the linearity was 0.992. These results demonstrate that the DNLPG CO2 gas sensor is highly sensitive.

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SnO2 Nano/Microfibers for Gas Sensors

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.405.324 ◽

2020 ◽

Vol 405 ◽

pp. 324-329

Author(s):

Erika Mudra ◽

Ivan Shepa ◽

Alexandra Kovalcikova ◽

Ondrej Milkovič ◽

Jan Dusza

Keyword(s):

Gas Sensors ◽

Gas Sensing ◽

Operating Temperature ◽

Band Gap Energy ◽

Calcination Process ◽

Sensing Applications ◽

Amorphous Nature ◽

Coating Method ◽

Type Semiconductor

SnO2 is an n-type semiconductor with the band gap energy of 3.6 eV. It has been widely studied for gas sensing applications, the sensitivity of which can be easily tuned by the operating temperature. The presented paper is focused on the preparation and detailed characterization of the hollow SnO2 nano/microfibers suitable for gas detection sensors. Ceramic SnO2 fibers were produced by needleless electrospinning and followed by the calcination process. The characterization was performed by SEM, TEM, XRD, and Raman spectroscopy. The precursor PVP/SnO2 fibers had amorphous nature. The calcination of the electro spun precursor resulted in the formation of hollow crystalline fibrous structures. The formation mechanism of hollow fibers has been described. Subsequently, a homogeneous fibrous layer was created by the spin coating method for gas sensing applications.

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Nanomaterial-based gas sensors used for breath diagnosis

Journal of Materials Chemistry B ◽

10.1039/c9tb02518a ◽

2020 ◽

Vol 8 (16) ◽

pp. 3231-3248 ◽

Cited By ~ 8

Author(s):

Xinyuan Zhou ◽

Zhenjie Xue ◽

Xiangyu Chen ◽

Chuanhui Huang ◽

Wanqiao Bai ◽

...

Keyword(s):

Physicochemical Properties ◽

Gas Sensors ◽

Active Sites ◽

Gas Sensing ◽

High Surface ◽

Volume Ratio ◽

Sensing Applications ◽

Enormous Number

Gas-sensing applications commonly use nanomaterials (NMs) because of their unique physicochemical properties, including a high surface-to-volume ratio, enormous number of active sites, controllable morphology, and potential for miniaturisation.

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Antiresonant Hollow-Core Fiber-Based Dual Gas Sensor for Detection of Methane and Carbon Dioxide in the Near- and Mid-Infrared Regions

Sensors ◽

10.3390/s20143813 ◽

2020 ◽

Vol 20 (14) ◽

pp. 3813 ◽

Cited By ~ 2

Author(s):

Piotr Jaworski ◽

Paweł Kozioł ◽

Karol Krzempek ◽

Dakun Wu ◽

Fei Yu ◽

...

Keyword(s):

Carbon Dioxide ◽

Gas Sensor ◽

Gas Sensing ◽

Simultaneous Detection ◽

Hollow Core ◽

Mid Infrared ◽

Sensing Applications ◽

Core Fiber ◽

Sensor Configuration ◽

Carbon Dioxide Co2

In this work, we present for the first time a laser-based dual gas sensor utilizing a silica-based Antiresonant Hollow-Core Fiber (ARHCF) operating in the Near- and Mid-Infrared spectral region. A 1-m-long fiber with an 84-µm diameter air-core was implemented as a low-volume absorption cell in a sensor configuration utilizing the simple and well-known Wavelength Modulation Spectroscopy (WMS) method. The fiber was filled with a mixture of methane (CH4) and carbon dioxide (CO2), and a simultaneous detection of both gases was demonstrated targeting their transitions at 3.334 µm and 1.574 µm, respectively. Due to excellent guidance properties of the fiber and low background noise, the proposed sensor reached a detection limit down to 24 parts-per-billion by volume for CH4 and 144 parts-per-million by volume for CO2. The obtained results confirm the suitability of ARHCF for efficient use in gas sensing applications for over a broad spectral range. Thanks to the demonstrated low loss, such fibers with lengths of over one meter can be used for increasing the laser-gas molecules interaction path, substituting bulk optics-based multipass cells, while delivering required flexibility, compactness, reliability and enhancement in the sensor’s sensitivity.

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Gas Sensing Properties of Mg-Incorporated Metal–Organic Frameworks

Sensors ◽

10.3390/s19153323 ◽

2019 ◽

Vol 19 (15) ◽

pp. 3323 ◽

Cited By ~ 4

Author(s):

Jae-Hyoung Lee ◽

Thanh-Binh Nguyen ◽

Duy-Khoi Nguyen ◽

Jae-Hun Kim ◽

Jin-Young Kim ◽

...

Keyword(s):

Pore Size ◽

Gas Sensors ◽

Gas Sensing ◽

High Surface ◽

Metal Organic Frameworks ◽

Kinetic Properties ◽

Sensing Properties ◽

Sensing Applications ◽

Gas Sensing Properties ◽

Metal Organic

The gas sensing properties of two novel series of Mg-incorporated metal–organic frameworks (MOFs), termed Mg-MOFs-I and -II, were assessed. The synthesized iso-reticular type Mg-MOFs exhibited good crystallinity, high thermal stability, needle-shape morphology and high surface area (up to 2900 m2·g−1), which are promising for gas sensing applications. Gas-sensing studies of gas sensors fabricated from Mg-MOFs-II revealed better sensing performance, in terms of the sensor dynamics and sensor response, at an optimal operating temperature of 200 °C. The MOF gas sensor with a larger pore size and volume showed shorter response and recovery times, demonstrating the importance of the pore size and volume on the kinetic properties of MOF-based gas sensors. The gas-sensing results obtained in this study highlight the potential of Mg-MOFs gas sensors for the practical monitoring of toxic gases in a range of environments.

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Ammonia Gas Detection by Tannic Acid Functionalized and Reduced Graphene Oxide at Room Temperature

Journal of Nanomaterials ◽

10.1155/2014/497384 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 40

Author(s):

Sweejiang Yoo ◽

Xin Li ◽

Yuan Wu ◽

Weihua Liu ◽

Xiaoli Wang ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Gas Sensor ◽

Tannic Acid ◽

Room Temperature ◽

Gas Sensing ◽

High Sensitivity ◽

Gas Detection ◽

Ammonia Gas ◽

Reduced Graphene

Reduced graphene oxide (rGO) based chemiresistor gas sensor has received much attention in gas sensing for high sensitivity, room temperature operation, and reversible. Here, for the first time, we present a promising chemiresistor for ammonia gas detection based on tannic acid (TA) functionalized and reduced graphene oxide (rGOTA functionalized). Green reductant of TA plays a major role in both reducing process and enhancing the gas sensing properties ofrGOTA functionalized. Our results showrGOTA functionalizedonly selective to ammonia with excellent respond, recovery, respond time, and recovery times.rGOTA functionalizedelectrical resistance decreases upon exposure to NH3where we postulated that it is due to n-doping by TA and charge transfer betweenrGOTA functionalizedand NH3through hydrogen bonding. Furthermore,rGOTA functionalizedhinders the needs for stimulus for both recovery and respond. The combination of greener sensing material and simplicity in overall sensor design provides a new sight for green reductant approach of rGO based chemiresistor gas sensor.

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