scholarly journals A Review: Application and Implementation of Optic Fibre Sensors for Gas Detection

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6755
Author(s):  
Thomas Allsop ◽  
Ronald Neal
Keyword(s):  
Optical Fibre ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Working Environment ◽  
Oxide Semiconductor ◽  
Binding Reaction ◽  
Long Period Gratings ◽  
Optic Fibre ◽  
Chemical Selectivity ◽  
Safe Working

At the present time, there are major concerns regarding global warming and the possible catastrophic influence of greenhouse gases on climate change has spurred the research community to investigate and develop new gas-sensing methods and devices for remote and continuous sensing. Furthermore, there are a myriad of workplaces, such as petrochemical and pharmacological industries, where reliable remote gas tests are needed so that operatives have a safe working environment. The authors have concentrated their efforts on optical fibre sensing of gases, as we became aware of their increasing range of applications. Optical fibre gas sensors are capable of remote sensing, working in various environments, and have the potential to outperform conventional metal oxide semiconductor (MOS) gas sensors. Researchers are studying a number of configurations and mechanisms to detect specific gases and ways to enhance their performances. Evidence is growing that optical fibre gas sensors are superior in a number of ways, and are likely to replace MOS gas sensors in some application areas. All sensors use a transducer to produce chemical selectivity by means of an overlay coating material that yields a binding reaction. A number of different structural designs have been, and are, under investigation. Examples include tilted Bragg gratings and long period gratings embedded in optical fibres, as well as surface plasmon resonance and intra-cavity absorption. The authors believe that a review of optical fibre gas sensing is now timely and appropriate, as it will assist current researchers and encourage research into new photonic methods and techniques.

scholarly journals Silver Enhances Hematite Nanoparticles Based Ethanol Sensor Response and Selectivity at Room Temperature

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 440
Author(s):  
Daniel Garcia-Osorio ◽  
Pilar Hidalgo-Falla ◽  
Henrique E. M. Peres ◽  
Josue M. Gonçalves ◽  
Koiti Araki ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Ethanol Vapor ◽  
Oxide Semiconductor ◽  
Charge Carrier Density ◽  
Ethanol Sensor ◽  
Volatile Organic

Gas sensors are fundamental for continuous online monitoring of volatile organic compounds. Gas sensors based on semiconductor materials have demonstrated to be highly competitive, but are generally made of expensive materials and operate at high temperatures, which are drawbacks of these technologies. Herein is described a novel ethanol sensor for room temperature (25 °C) measurements based on hematite (α‑Fe2O3)/silver nanoparticles. The AgNPs were shown to increase the oxide semiconductor charge carrier density, but especially to enhance the ethanol adsorption rate boosting the selectivity and sensitivity, thus allowing quantification of ethanol vapor in 2–35 mg L−1 range with an excellent linear relationship. In addition, the α-Fe2O3/Ag 3.0 wt% nanocomposite is cheap, and easy to make and process, imparting high perspectives for real applications in breath analyzers and/or sensors in food and beverage industries. This work contributes to the advance of gas sensing at ambient temperature as a competitive alternative for quantification of conventional volatile organic compounds.

scholarly journals Discriminable Sensing Response Behavior to Homogeneous Gases Based on n-ZnO/p-NiO Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 785 ◽  
Author(s):  
Wen-Dong Zhou ◽  
Davoud Dastan ◽  
Jing Li ◽  
Xi-Tao Yin ◽  
Qi Wang
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Sol Gel ◽  
High Sensitivity ◽  
Oxide Semiconductor ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
P Type ◽  
Type Response ◽  
Properties Of Composites

Metal oxide semiconductor (MOS) gas sensors have the advantages of high sensitivity, short response-recovery time and long-term stability. However, the shortcoming of poor discriminability of homogeneous gases limits their applications in gas sensors. It is well-known that the MOS materials have similar gas sensing responses to homogeneous gases such as CO and H2, so it is difficult for these gas sensors to distinguish the two gases. In this paper, simple sol–gel method was employed to obtain the ZnO–xNiO composites. Gas sensing performance results illustrated that the gas sensing properties of composites with x > 0.425 showed a p-type response to both CO and H2, while the gas sensing properties of composites with x < 0.425 showed an n-type response to both CO and H2. However, it was interesting that ZnO–0.425NiO showed a p-type response to CO but an discriminable response (n-type) to H2, which indicated that modulating the p-type or n-type semiconductor concentration in p-n composites could be an effective method with which to improve the discriminability of this type of gas sensor regarding CO and H2. The phenomenon of the special gas sensing behavior of ZnO–0.425NiO was explained based on the experimental observations and a range of characterization techniques, including XRD, HRTEM and XPS, in detail.

scholarly journals 3D Gas Distribution with and without Artificial Airflow: An Experimental Study with a Grid of Metal Oxide Semiconductor Gas Sensors

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 911 ◽  
Author(s):  
Javier Burgués ◽  
Victor Hernandez ◽  
Achim J. Lilienthal ◽  
Santiago Marco
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Three Dimensional ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Wind Tunnels ◽  
Gaseous Emissions ◽  
Gas Distribution ◽  
Life Saving

Gas distribution modelling can provide potentially life-saving information when assessing the hazards of gaseous emissions and for localization of explosives, toxic or flammable chemicals. In this work, we deployed a three-dimensional (3D) grid of metal oxide semiconductor (MOX) gas sensors deployed in an office room, which allows for novel insights about the complex patterns of indoor gas dispersal. 12 independent experiments were carried out to better understand dispersion patters of a single gas source placed at different locations of the room, including variations in height, release rate and air flow profiles. This dataset is denser and richer than what is currently available, i.e., 2D datasets in wind tunnels. We make it publicly available to enable the community to develop, validate, and compare new approaches related to gas sensing in complex environments.

Pure and Pr-doped Ce4W9O33 with superior hydroxyl scavenging ability: Humidity-independent oxide chemiresistors

2021 ◽  
Author(s):  
Jun-Sik Kim ◽  
Ki Beom Kim ◽  
Huayao Li ◽  
Chan Woong Na ◽  
Kyeorei Lim ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Oxide Semiconductor ◽  
Semiconductor Gas Sensors ◽  
First Time ◽  
Sensing Characteristics ◽  
Standing Problem

Water poisoning has been a long-standing problem in oxide semiconductor gas sensors. Herein, for the first time, we report that pure and Pr-doped Ce4W9O33 provide humidity-independent gas sensing characteristics. The...

scholarly journals Gas Sensors Based on Oxide Semiconductors with Porous Nanostructures

Proceedings ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 13
Author(s):  
Peng Sun
Keyword(s):  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Synergistic Effects ◽  
Response Speed ◽  
High Specific Surface Area ◽  
Oxide Semiconductor ◽  
Oxide Semiconductors ◽  
Sensing Properties ◽  
Porous Nanostructures

Gas sensor as a device composed of sensing material coupled with signal transducer, has been acknowledged as an analytical tool for detection and quantification of inflammable, explosive or toxic gases. The gas sensors based on nanostructured oxide semiconductor endowed with excellent sensing properties have exhibited great potential application in the fields of environmental monitoring, resource exploration, medical welfare, etc. It is well known that the sensing mechanism of sensor employing oxide semiconductors is mainly that the interactions between the surface adsorbed oxygen species and target gases lead to a change in the electrical conductivity. Therefore, the gas sensing properties of oxide semiconductors are closely related with their composition, crystalline size, and microstructure. In this regard, design and preparation of oxides with novel architectures will be increasingly important in the construction of high performance gas sensors. Due to high specific surface area, low density, and good surface permeability, porous nanostructures oxide semiconductor sensing materials have attracted growing interest in recent years. In our work, we successfully prepared various porous nanostructures oxides and their composites to the construction of high performances gas sensors with enhanced sensitivity, selectivity, as well as lowered detection limit. The subsequent gas sensing measurements explicitly revealed that these oxides and composites manifested superior sensing behaviors (like much higher sensitivity and faster response speed), which can be ascribed to the porous architectures and the synergistic effects.

scholarly journals Metal Oxide Semiconductor: Future Material for Gas Sensors and it’s Synthesis Techniques

2019 ◽  
Vol 8 (6S3) ◽  
pp. 1615-1619
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Oxide Semiconductors ◽  
Methods Of Synthesis

This paper provides a complete idea about metal oxide semiconductors ((MOSs) for gas sensing application. Metal oxide semiconductor nano-materials are showing much higher strength in many industries, research laboratories and public health and so on with their effective chemical, physical, and electronic properties. The morphology, band gap, porosity, conductivity properties, low cost and high surface area etc. are few of the properties of MOSs that are responsible for the enhancement of sensing properties in various applications. Besides these, now-a-days MOSs are grown in different nanostructures like nano rods, nano flowers, nano sheets, nanowires etc. using the various growth techniques which are further responsible for their betterment as gas sensors. Therefore, this paper gives a complete idea about the different methods of synthesis of MOSs.

scholarly journals Improving Gas-Sensing Performance Based on MOS Nanomaterials: A Review

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4263
Author(s):  
Shirui Xue ◽  
Sicheng Cao ◽  
Zhaoling Huang ◽  
Daoguo Yang ◽  
Guoqi Zhang
Keyword(s):  
Gas Sensors ◽  
Agricultural Production ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Oxide Semiconductor ◽  
Sensing Properties ◽  
Advantages And Disadvantages ◽  
Short Recovery Time ◽  
Gas Sensing Properties

In order to solve issues of air pollution, to monitor human health, and to promote agricultural production, gas sensors have been used widely. Metal oxide semiconductor (MOS) gas sensors have become an important area of research in the field of gas sensing due to their high sensitivity, quick response time, and short recovery time for NO2, CO2, acetone, etc. In our article, we mainly focus on the gas-sensing properties of MOS gas sensors and summarize the methods that are based on the interface effect of MOS materials and micro–nanostructures to improve their performance. These methods include noble metal modification, doping, and core-shell (C-S) nanostructure. Moreover, we also describe the mechanism of these methods to analyze the advantages and disadvantages of energy barrier modulation and electron transfer for gas adsorption. Finally, we put forward a variety of research ideas based on the above methods to improve the gas-sensing properties. Some perspectives for the development of MOS gas sensors are also discussed.

Metal-oxide based ammonia gas sensors: A review

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.

scholarly journals On the Use of MOFs and ALD Layers as Nanomembranes for the Enhancement of Gas Sensors Selectivity

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1552 ◽  
Author(s):  
Weber ◽  
Graniel ◽  
Balme ◽  
Miele ◽  
Bechelany
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Metal Organic Frameworks ◽  
Atomic Layer ◽  
Operational Performance ◽  
Layer Deposition ◽  
Metal Organic ◽  
Further Development ◽  
Different Gases

Improving the selectivity of gas sensors is crucial for their further development. One effective route to enhance this key property of sensors is the use of selective nanomembrane materials. This work aims to present how metal-organic frameworks (MOFs) and thin films prepared by atomic layer deposition (ALD) can be applied as nanomembranes to separate different gases, and hence improve the selectivity of gas sensing devices. First, the fundamentals of the mechanisms and configuration of gas sensors will be given. A selected list of studies will then be presented to illustrate how MOFs and ALD materials can be implemented as nanomembranes and how they can be implemented to improve the operational performance of gas sensing devices. This review comprehensively shows the benefits of these novel selective nanomaterials and opens prospects for the sensing community.

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