Ammonia Gas Sensors: Comparison of Solid-State and Optical Methods

High precision and fast measurement of gas concentrations is important for both understanding and monitoring various phenomena, from industrial and environmental to medical and scientific applications. This article deals with the recent progress in ammonia detection using in-situ solid-state and optical methods. Due to the continuous progress in material engineering and optoelectronic technologies, these methods are among the most perceptive because of their advantages in a specific application. We present the basics of each technique, their performance limits, and the possibility of further development. The practical implementations of representative examples are described in detail. Finally, we present a performance comparison of selected practical application, accumulating data reported over the preceding decade, and conclude from this comparison.

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Ammonia Gas Sensors Based on In Situ and Drop-Coated Polyaniline Nanostructures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.685.134 ◽

2013 ◽

Vol 685 ◽

pp. 134-138 ◽

Cited By ~ 3

Author(s):

Houria Kebiche ◽

D. Debarnot ◽

A. Merzouki ◽

F. Poncin-Epaillard ◽

N. Haddaoui

Keyword(s):

Gas Sensors ◽

Strong Dependence ◽

Deposition Method ◽

Ammonia Gas ◽

Optical Absorbance ◽

Glass Substrates ◽

Mechanism Of Interaction ◽

Ammonia Gas Sensors

Polyaniline (PANI) nanostructures are successfully prepared and deposited by in-situ and drop-coating on glass substrates without using any template. By changing synthesis and deposition method, a new morphology of nanostructures, “the cauliflower-like structure”, is developed. These nanostructures were then tested as optical ammonia gas sensors by measuring the optical absorbance variations at 632 nm at different NH3 concentrations. The results show a strong dependence of the morphology on the deposition method. The in-situ one leads to better performances compared to the drop coated one. Protonation /deprotonation is the mechanism of interaction between NH3 molecules and PANI nanostructures.

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In-situ self-assembled polyaniline/carbon nanotubes nanofiber thin films for ammonia gas sensors

10.1117/12.866967 ◽

2010 ◽

Author(s):

Huiling Tai ◽

Yadong Jiang ◽

Guangzhong Xie

Keyword(s):

Thin Films ◽

Carbon Nanotubes ◽

Gas Sensors ◽

Ammonia Gas ◽

Self Assembled ◽

Ammonia Gas Sensors

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Dielectric and gas sensing properties of in situ electrochemically polymerized PPy-MgO-WO3 nanocomposite films

Iraqi Journal of Science ◽

10.24996/ijs.2021.62.9.8 ◽

2021 ◽

pp. 2915-2933

Author(s):

Yahya Abbas ◽

Ahmed Abbas

Keyword(s):

Indium Tin Oxide ◽

Gas Sensing ◽

Metal Oxide Nanoparticles ◽

Nanocomposite Films ◽

Ammonia Gas ◽

Weight Percentage ◽

Polypyrrole Films ◽

Gas Sensing Properties ◽

Ammonia Detection

A polypyrrole-based ammonia-detection gas sensor was studied in this work. Under a 1.6 V electrodeposition potential, polypyrrole (PPy) was electrochemically synthesized from an aqueous solution of 0.1 M pyrrole and 0.1 M oxalic acid. An extension to the polypyrrole films was applied through electrochemical deposition on indium tin oxide (ITO), using the metal oxide nanoparticles of MgO and WO3. These films were investigated for their sensing behavior towards NH3 at different working temperatures and different weight percentages of nanoparticles .The measurements of A.C conductivity were conducted over a frequency range of 101-105 Hz and temperature range of 298-423 K . The highest electrical conductivity was equal to 3.67x10-1 Ω.cm-1 at a temperature of 323 K and frequency of 105H z. The experimental results showed that the sensitivity of the undoped and doped PPy with nanoparticle films to ammonia gas changes with the change in temperature and weight percentage.

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The Nature of Chemisorbed CO2 in Zeolite A

10.26434/chemrxiv.7422815 ◽

2019 ◽

Author(s):

Przemyslaw Rzepka ◽

Zoltán Bacsik ◽

Andrew J. Pell ◽

Niklas Hedin ◽

Aleksander Jaworski

Keyword(s):

Solid State ◽

Ir Spectroscopy ◽

Quantum Chemical Calculations ◽

Quantum Chemical ◽

Surface Coverage ◽

Gas Mixtures ◽

Mas Nmr ◽

Significant Fraction ◽

Zeolite A

Formation of CO32- and HCO3- species without participation of the framework oxygen atoms upon chemisorption of CO2 in zeolite |Na12|-A is revealed. The transfer of O and H atoms is very likely to have proceeded via the involvement of residual H2O or acid groups. A combined study by solid-state 13C MAS NMR, quantum chemical calculations, and in situ IR spectroscopy showed that the chemisorption mainly occurred by the formation of HCO3-. However, at a low surface coverage of physisorbed and acidic CO2, a significant fraction of the HCO3- was deprotonated and transformed into CO32-. We expect that similar chemisorption of CO2 would occur for low-silica zeolites and other basic silicates of interest for the capture of CO2 from gas mixtures.

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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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