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Mechanistic understanding of transition-metal-decorated biphenylene for highly selective NO2 and NH3 detection
(2026-06-15)
Wongphen, Kantaphong
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Khammuang, Satchakorn
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Oo, Ghaim Man
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Hussain, Tanveer
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Kotmool, Komsilp
Here, we employ density functional theory (DFT) in combination with ab initio molecular dynamics (AIMD) simulations to examine the sensing performance of biphenylene doped with selected transition-metal dopants (M@BP), specifically Fe, Co, and Ni, on NO<inf>2</inf> and NH<inf>3</inf>. The results indicate that NO<inf>2</inf> exhibits stronger interaction than NH<inf>3</inf>, with adsorption energies ( E<inf>ads</inf> ) exceeding -3.0 eV. In contrast, the E<inf>ads</inf> values for NH<inf>3</inf> are around -1.30 eV. Bader charge and electron density difference (EDD) analyses reveal that charge is transferred from the M@BP monolayers to NO<inf>2</inf>. In contrast, the charge transfer occurs in the opposite direction for NH<inf>3</inf>, indicating distinct chemical adsorption mechanisms. Additionally, the electron localization function (ELF) results indicate partial ionic bonding and localized charge sharing between the metal sites of M@BP and the gas molecules. Variations in the work function, alongside calculated sensitivity (S) values, demonstrate that M@BP is exceptionally responsive to NH<inf>3</inf>, with S values of 13.4 %, 8.7 %, and 13.7 % for Fe@BP, Co@BP, and Ni@BP, respectively. These materials exhibit strong potential as reusable gas sensors capable of operating at temperatures above 500 K while maintaining practical recovery times. Moreover, AIMD simulations confirm the thermal stability of Co@BP and Ni@BP, whereas Fe@BP exhibits instability at 600 K. These findings suggest that M@BP possess a strong affinity for NH<inf>3</inf>, tunable electronic properties, and excellent thermal stability, making them promising candidates for selective, reusable high-temperature gas-sensor applications.
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Hybrid gas sensor based on platinum nanoparticles/poly(methyl methacrylate)-coated single-walled carbon nanotubes for dichloromethane detection with a high response magnitude
(2016-05-01)
Muangrat, Worawut
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Yordsri, Visittapong
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Maolanon, Rungroj
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Pratontep, Sirapat
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Porntheeraphat, Supanit
A dichloromethane (DCM) sensor with a high response magnitude was successfully fabricated using the integration of single-walled carbon nanotubes (SWNTs), poly(methyl methacrylate) (PMMA) and platinum nanoparticles (Pt NPs). A pristine SWNT network was first formed by drop-casting onto printed circuit board (PCB) substrates. Next, PMMA was coated onto the pre-dropped SWNT network by spin coating using a PMMA-toluene solution, followed by the deposition of Pt NPs by electron-beam evaporation (hereafter referred to as Pt/PMMA/SWNT). The Pt/PMMA/SWNT enabled an approximately 69-fold improvement in DCM detection compared to pristine SWNT. The high response magnitude of the Pt/PMMA/SWNT was successfully achieved because of the incorporation of PMMA and Pt functions. Swelling of the PMMA matrix as a result of DCM adsorption leads to PMMA volume expansion, thereby increasing the SWNT-SWNT distance, which results in an increase in the resistance. Pt NPs promote the dissociation of DCM to CO, and consequently the CO oxidation on the Pt NPs catalyst and electron donation from Pt NPs to SWNTs, resulting in an increase in the resistance. Moreover, a linear relationship was obtained between the sensor response of the Pt/PMMA/SWNT and the concentration of DCM. These results suggest that the integration of SWNTs with PMMA and Pt NPs is a promising approach for improving DCM detection at room temperature.
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A nano-scale transducer using a PANDA type ring resonator for gas sensor applications
(2012-03-01)
Srinuanjan, Keerayoot
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Kamoldilok, Surachart
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Tipaphong, Weraphan
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Yupapin, Preecha P.
We present a new system of nano-scale gas sensor using PANDA type ring resonator, whereas the sensing unit is a splitting ring resonator with two and four gaps. The method of finite difference time domain (FDTD) via the computer programming called Opti-wave was used to analyze and simulated all the parameters. The two systems were compared and the simulation result shown that the system of four splitting gaps is better resolution and more linear relationship than two splitting gaps unit. Finally, we found that this system can be used to be a high-precision self-calibration nano-scale gas sensor with in the of resolution of 1 nm. © 2011 Elsevier GmbH. All rights reserved.
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An artificial nose based on M-porphyrin (M = Mg, Zn) thin film and optical spectroscopy
(2011-12-01)
Kladsomboon, Sumana
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Pratontep, Sirapat
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Puntheeranurak, Theeraporn
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Kerdcharoen, Teerakiat
Artificial nose has recently become an emerging instrument for quality assurance in the food industry. These paper present the optical gas sensors based on Magnesium-5,10,15,20-tetra phenyl-porphyrin (MgTPP) and Zinc-5,10,15,20-tetra phenyl-porphyrin (ZnTPP) thin films and their application as an artificial nose. Based on the measurement of optical absorbance response using a general UV-Vis spectroscopy, this artificial nose was tested to discriminate various volatile organic compounds (VOCs) and Thai beverages. Atomic force microscopy (AFM) and X-rays diffraction (XRD) were used to confirm the polycrystalline structure of the sensing materials. Density functional theory (DFT) calculations reveal that MgTPP interacts more strongly with the VOCs than ZnTPP, especially with methanol. The classification results of VOCs and Thai beverage vapors using the principal component analysis indicate that both MgTPP and ZnTPP-based artificial noses can be an efficient tool for quality assurance of alcoholic beverages. Copyright © 2011 American Scientific Publishers All rights reserved.
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Improved selectivity, response time and recovery time by [0 1 0] highly preferred-orientation silicalite-1 layer coated on SnO2 thin film sensor for selective ethylene gas detection
(2010-01-29)
Jadsadapattarakul, Damrongsak
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Thanachayanont, Chanchana
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Nukeaw, Jiti
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Sooknoi, Tawan
In this work, sensing response, response time and recovery time for selective ethylene gas detection were improved by coating a layer of [0 1 0] highly preferred-orientation silicalite-1 polycrystals on SnO<inf>2</inf> thin film sensors. The sensors were prepared by primarily depositing SnO<inf>2</inf> on borosilicate glass substrates using ultrasonic spray pyrolysis technique. Conventional and [0 1 0] preferred orientations of silicalite-1 layers were then directly coated on the SnO<inf>2</inf> thin film sensors by hydrothermal crystallization technique with different gel compositions. The silicalite-1/SnO<inf>2</inf> thin film sensors were calcined at 550 °C in dry air. The crystal structure and surface morphology of SnO<inf>2</inf> and silicalite-1 layers were characterized by XRD and SEM techniques. XANES and TPR were used to verify oxidation state and reduction temperature of the SnO<inf>2</inf> thin film sensors, respectively. The interaction of C<inf>2</inf>H<inf>4</inf> and H<inf>2</inf>O with silicalite-1 was determined by TPD. The sensing performances, such as selectivity, dynamic range, response time and recovery time were evaluated for the C<inf>2</inf>H<inf>4</inf> and H<inf>2</inf>O. The results showed that the incorporated silicalite-1 layers readily improve the C<inf>2</inf>H<inf>4</inf> selectivity and dynamic range by preferential adsorption of C<inf>2</inf>H<inf>4</inf> molecules on the silicalite-1 filtering layers. The response time and recovery time for the [0 1 0] highly preferred-orientation silicalite-1/SnO<inf>2</inf> thin film sensor (t<inf>90%</inf>, 14 and 144 s) were shorter than those of the conventional one (t<inf>90%</inf>, 25 and 208 s). It is suggested that the [0 1 0] preferred-orientation silicalite-1, with a pore direction perpendicular to SnO<inf>2</inf> thin film surface, can accelerate the molecular diffusion and reduce the diffusion pathway of ethylene to the sensing film. © 2009 Elsevier B.V.
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SiO2-Multiwalled carbon nanotube base gas sensor
(2008-12-01)
Jesen, S.
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Ruangphet, S.
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Cheirsirikul, S.
The gas sensors are fabricated from multiwalled carbon nanotube-based. The electrode is constructed from platinum (Pt) and titanium (Ti). The gas sensors are used for detecting oxygen (O<inf>2</inf>), ethyl alcohol (C <inf>2</inf>H<inf>5</inf>OH) and ammonia (NH<inf>3</inf>) by measuring the charge of their electrical capacitance. In the ratio silicon dioxide (SiO <inf>2</inf>) : carbon nanotube (MWCNTs) = 100:1 by weight, the electrical capacitance of the film layer has changed at the highest rate. The response of oxygen with concentration of 10,000 ppm, 20% of ethyl alcohol and 20% of ammonia, it is found that the electrical capacitance of thin layer has change about 34%, 60% and 70%. © 2008 Trans Tech Publications, Switzerland.
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Adsorption kinetics of NO2 on single-walled carbon nanotube thin-film sensor
(2008-10-01)
Wongwiriyapan, Winadda
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Inoue, Satoshi
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Honda, Shin ichi
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Katayama, Mitsuhiro
The adsorption kinetics of NO<inf>2</inf> on a single-walled carbon nanotube (SWNT) thin-film sensor was investigated. To avoid the influence of ambient air, the adsorption property of SWNTs was explored under high vacuum. By virtue of the suppression of the influence of residual gases and the cleanness of the SWNT surface in vacuum, the SWNTs exhibited high sensitivity with a detection limit of lower than 1 ppb. On the basis of the Langmuir adsorption isotherm, the sticking probability and adsorption energy of NO<inf>2</inf> molecules on SWNTs were experimentally estimated. © 2008 The Japan Society of Applied Physics.

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