scholarly journals Development of a Novel Gas-Sensing Platform Based on a Network of Metal Oxide Nanowire Junctions Formed on a Suspended Carbon Nanomesh Backbone

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4525
Author(s):  
Taejung Kim ◽  
Seungwook Lee ◽  
Wootaek Cho ◽  
Yeong Min Kwon ◽  
Jeong Min Baik ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Microelectromechanical Systems ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Sensing Platform ◽  
Batch Fabrication ◽  
Sensor Platform ◽  
Carbon Microelectromechanical Systems

Junction networks made of longitudinally connected metal oxide nanowires (MOx NWs) have been widely utilized in resistive-type gas sensors because the potential barrier at the NW junctions leads to improved gas sensing performances. However, conventional MOx–NW-based gas sensors exhibit limited gas access to the sensing sites and reduced utilization of the entire NW surfaces because the NW networks are grown on the substrate. This study presents a novel gas sensor platform facilitating the formation of ZnO NW junction networks in a suspended architecture by growing ZnO NWs radially on a suspended carbon mesh backbone consisting of sub-micrometer-sized wires. NW networks were densely formed in the lateral and longitudinal directions of the ZnO NWs, forming additional longitudinally connected junctions in the voids of the carbon mesh. Therefore, target gases could efficiently access the sensing sites, including the junctions and the entire surface of the ZnO NWs. Thus, the present sensor, based on a suspended network of longitudinally connected NW junctions, exhibited enhanced gas response, sensitivity, and lower limit of detection compared to sensors consisting of only laterally connected NWs. In addition, complete sensor structures consisting of a suspended carbon mesh backbone and ZnO NWs could be prepared using only batch fabrication processes such as carbon microelectromechanical systems and hydrothermal synthesis, allowing cost-effective sensor fabrication.

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 Advanced development of metal oxide nanomaterials for H2 gas sensing applications

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.

scholarly journals Flexible Gas Sensors: Glass-Fabric Reinforced Ag Nanowire/Siloxane Composite Heater Substrate: Sub-10 nm Metal@Metal Oxide Nanosheet for Sensitive Flexible Sensing Platform (Small 44/2018)

Small ◽  
2018 ◽  
Vol 14 (44) ◽  
pp. 1870201 ◽  
Author(s):  
Ji-Soo Jang ◽  
Young-Woo Lim ◽  
Dong-Ha Kim ◽  
Daewon Lee ◽  
Won-Tae Koo ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Glass Fabric ◽  
Sensing Platform ◽  
Metal Metal ◽  
Ag Nanowire

Development of Synergistic Opto-Electronic Sensing Platform based on Zinc Oxide Semiconducting Nanostructures

2012 ◽  
Vol 2012 (1) ◽  
pp. 001191-001196
Author(s):  
Anurag Gupta ◽  
Bruce C. Kim ◽  
Mitchell Spryn ◽  
Eugene Edwards ◽  
Christina Brantley ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Cost Effective ◽  
Zinc Oxide Nanowires ◽  
Oxide Nanowires ◽  
Sensing Platform ◽  
Sensor Platform ◽  
Semiconducting Nanostructures ◽  
Ft Ir ◽  
Characterization Studies ◽  
Electronic Sensing

Potential of zinc oxide nanowires for developing a sensitive opto-electronic platform was demonstrated. Zinc oxide nanowires synthesized on insulating sapphire substrates were functionalized with an optically active receptor, 1-pyrenebutyric acid. Appropriate characterization studies including XPS and FT-IR ATR are reported. I-V curves of pristine and receptor-modified nanowires were utilized to highlight the potential of zinc oxide nano-heterostructures for developing a sensitive opto-electronic platform for p-nitrophenol sensing. Packaging issues for achieving an efficient and cost-effective sensor platform have also been outlined.

Applications of Nanostructured Materials as Gas Sensors

2013 ◽  
Vol 201 ◽  
pp. 131-158 ◽  
Author(s):  
Ravi Chand Singh ◽  
Manmeet Pal Singh ◽  
Hardev Singh Virk
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Dominant Role ◽  
Low Cost ◽  
Critical Role ◽  
Health And Safety ◽  
Chemical Route ◽  
Metal Oxide Sensors

Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring, and process control. To meet this demand, considerable research into new sensors is underway, including efforts to enhance the performance of traditional devices, such as resistive metal oxide sensors, through nanoengineering. The resistance of semiconductors is affected by the gaseous ambient. The semiconducting metal oxides based gas sensors exploit this phenomenon. Physical chemistry of solid metal surfaces plays a dominant role in controlling the gas sensing characteristics. Metal oxide sensors have been utilized for several decades for low-cost detection of combustible and toxic gases. Recent advances in nanomaterials provide the opportunity to dramatically increase the response of these materials, as their performance is directly related to exposed surface volume. Proper control of grain size remains a key challenge for high sensor performance. Nanoparticles of SnO2have been synthesized through chemical route at 5, 25 and 50°C. The synthesized particles were sintered at 400, 600 and 800°C and their structural and morphological analysis was carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The reaction temperature is found to be playing a critical role in controlling nanostructure sizes as well as agglomeration. It has been observed that particle synthesized at 5 and 50°C are smaller and less agglomerated as compared to the particles prepared at 25°C. The studies revealed that particle size and agglomeration increases with increase in sintering temperature. Thick films gas sensors were fabricated using synthesized tin dioxide powder and sensing response of all the sensors to ethanol vapors was investigated at different temperatures and concentrations. The investigations revealed that sensing response of SnO2nanoparticles is size dependent and smaller particles display higher sensitivity. Table of Contents

scholarly journals Development of a Cost-Effective Sensing Platform for Monitoring Phosphate in Natural Waters

Chemosensors ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 57 ◽  
Author(s):  
Andrew Donohoe ◽  
Gareth Lacour ◽  
Peter McCluskey ◽  
Dermot Diamond ◽  
Margaret McCaul
Keyword(s):  
Natural Waters ◽  
Limit Of Detection ◽  
Low Cost ◽  
Unit Cost ◽  
High Standard ◽  
Cost Effective ◽  
Remote Access ◽  
Sampling Location ◽  
Sensing Platform

A sensing platform for the in situ, real-time analysis of phosphate in natural waters has been realised using a combination of microfluidics, colorimetric reagent chemistries, low-cost LED-based optical detection and wireless communications. Prior to field deployment, the platform was tested over a period of 55 days in the laboratory during which a total of 2682 autonomous measurements were performed (854 each of sample, high standard and baseline, and 40 × 3 spiked solution measurements). The platform was subsequently field-deployed in a freshwater stream at Lough Rea, Co., Galway, Ireland, to track changes in phosphate over a five day period. During this deployment, 165 autonomous measurements (55 each of sample, high standard, and baseline) were performed and transmitted via general packet radio service (GPRS) to a web interface for remote access. Increases in phosphate levels at the sampling location coincident with rainfall events (min 1.45 µM to max 10.24 µM) were detected during the deployment. The response was found to be linear up to 50 µM PO43−, with a lower limit of detection (LOD) of 0.09 µM. Laboratory and field data suggest that despite the complexity of reagent-based analysers, they are reasonably reliable in remote operation, and offer the best opportunity to provide enhanced in situ chemical sensing capabilities. Modifications that could further improve the reliability and scalability of these platforms while simultaneously reducing the unit cost are discussed.

scholarly journals High-Performance Gas Sensor of Polyaniline/Carbon Nanotube Composites Promoted by Interface Engineering

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 149 ◽  
Author(s):  
Weiyu Zhang ◽  
Shuai Cao ◽  
Zhaofeng Wu ◽  
Min Zhang ◽  
Yali Cao ◽  
...  
Keyword(s):  
High Performance ◽  
Structural Changes ◽  
Gas Sensing ◽  
Response Times ◽  
Limit Of Detection ◽  
Hierarchical Structures ◽  
Cost Effective ◽  
One Dimensional ◽  
P Type ◽  
Sensing Performance

Inspired by the enhanced gas-sensing performance by the one-dimensional hierarchical structure, one-dimensional hierarchical polyaniline/multi-walled carbon nanotubes (PANI/CNT) fibers were prepared. Interestingly, the simple heating changed the sensing characteristics of PANI from p-type to n-type and n-type PANI and p-type CNTs form p–n hetero junctions at the core–shell interface of hierarchical PANI/CNT composites. The p-type PANI/CNT (p-PANI/CNT) and n-type PANI/CNT (n-PANI/CNT) performed the higher sensitivity to NO2 and NH3, respectively. The response times of p-PANI/CNT and n-PANI/CNT to 50 ppm of NO2 and NH3 are only 5.2 and 1.8 s, respectively, showing the real-time response. The estimated limit of detection for NO2 and NH3 is as low as to 16.7 and 6.4 ppb, respectively. After three months, the responses of p-PANI/CNT and n-PANI/CNT decreased by 19.1% and 11.3%, respectively. It was found that one-dimensional hierarchical structures and the deeper charge depletion layer enhanced by structural changes of PANI contributed to the sensitive and fast responses to NH3 and NO2. The formation process of the hierarchical PANI/CNT fibers, p–n transition, and the enhanced gas-sensing performance were systematically analyzed. This work also predicts the development prospects of cost-effective, high-performance PANI/CNT-based sensors.

scholarly journals WO3 Based Gas Sensors

Proceedings ◽  
2019 ◽  
Vol 2 (13) ◽  
pp. 826 ◽  
Author(s):  
Anna Staerz ◽  
Simona Somacescu ◽  
Mauro Epifani ◽  
Tamara Russ ◽  
Udo Weimar ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Gas Sensing

WO3 is a commonly used material for gas sensing. Although a great deal of research has been done on how to tune sensors based on WO3, no clear consensus exists on what characteristics are inherent to the metal oxide: This work looks at six different WO3 samples and aims to identify which characteristics are common to all materials. Specifically, the interaction of the samples with humidity is examined.

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