ZnO functionalization of multiwalled carbon nanotubes for methane sensing at single parts per million concentration levels

Humayun, Tanim; Divan, Ralu; Stan, Liliana; Gupta, Ashu; Rosenmann, Daniel; Gundel, Lara A.; Solomon, Paul A.; Paprotny, Igor

doi:10.1116/1.4931694

Cited by 20 publications

(17 citation statements)

References 21 publications

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“…365 More recently, Paprotny and coworkers demonstrated CH 4 sensors using MWCNTs functionalized with metal oxide NPs (either SnO 2 or ZnO) through atomic layer deposition (ALD). 366,367 Both chemiresistors functioned at room temperature and were sensitive to ppm levels of methane in dry air. 366,367 The proposed mechanism involved the adsorption of CH 4 molecules on the metal oxide NPs, leading to the increase in the sensor’s relative resistance.…”

Section: Cnt-based Sensors For Environmental Monitoringmentioning

confidence: 99%

Carbon Nanotube Chemical Sensors

et al. 2018

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Carbon nanotubes (CNTs) promise to advance a number of real-world technologies. Of these applications, they are particularly attractive for uses in chemical sensors for environmental and health monitoring. However, chemical sensors based on CNTs are often lacking in selectivity, and the elucidation of their sensing mechanisms remains challenging. This review is a comprehensive description of the parameters that give rise to the sensing capabilities of CNT-based sensors and the application of CNT-based devices in chemical sensing. This review begins with the discussion of the sensing mechanisms in CNT-based devices, the chemical methods of CNT functionalization, architectures of sensors, performance parameters, and theoretical models used to describe CNT sensors. It then discusses the expansive applications of CNT-based sensors to multiple areas including environmental monitoring, food and agriculture applications, biological sensors, and national security. The discussion of each analyte focuses on the strategies used to impart selectivity and the molecular interactions between the selector and the analyte. Finally, the review concludes with a brief outlook over future developments in the field of chemical sensors and their prospects for commercialization.

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Section: Cnt-based Sensors For Environmental Monitoringmentioning

confidence: 99%

Carbon Nanotube Chemical Sensors

et al. 2018

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“…Much effort has been made to reduce the operating temperature to room temperature, mainly to reduce the energy waste during sensors operation and to avoid gas explosion in the presence of flammable and explosive gases. To this aim, several approaches [9] have been explored, like doping with metals, modifying ZnO surface/defectivity or, finally, preparing ZnO-based composites in order to increase the conductivity of the oxide [9,10,11,12,13,14,15,16]. However, most of the papers report the use of thermal treatments for the sensitive layer preparation, both for bare ZnO layers and for ZnO-based composites, and, furthermore, the use of relatively high (>150 °C) operating temperatures for sensing devices.…”

Section: Introductionmentioning

confidence: 99%

Investigation of ZnO-decorated CNTs for UV Light Detection Applications

et al. 2019

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Multi-walled carbon nanotubes (CNTs) decorated with zinc oxide nanoparticles (ZnO NPs) were prepared in isopropanol solution by a simple, room-temperature process and characterized from structural, morphological, electronic, and optical points of view. A strong interaction between ZnO and CNTs is fully confirmed by all the characterization techniques. ZnO-CNTs nanocomposites, with different weight ratios, were deposited as a dense layer between two electrodes, in order to investigate the electrical behaviour. In particular, the electrical response of the nanocomposite layers to UV light irradiation was recorded for a fixed voltage: As the device is exposed to the UV lamp, a sharp current drop takes place and then an increase is observed as the irradiation is stopped. The effect can be explained by adsorption and desorption phenomena taking place on the ZnO nanoparticle surface under irradiation and by charge transfer between ZnO and CNTs, thanks to the strong interaction between the two nanomaterials. The nanocomposite material shows good sensitivity and fast response to UV irradiation. Room temperature and low-cost processes used for the device preparation combined with room temperature and low voltage operational conditions make this methodology very promising for large scale UV detectors applications.

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“…Details on the fabrication process can be found elsewhere. 25 MWCNT (98% pure) with an average diameter of 12 nm, an average length of 10 lm, and a specific surface area of 220 m 2 /g was purchased from Sigma Aldrich. Using a microsyringe, an aliquot of 50 ll from a 1 g/50 ml solution of MWCNT-ethanol was deposited on an active area of 1 mm 2 on the fabricated Au electrodes.…”

Section: A Sensor Fabricationmentioning

confidence: 99%

“…Using diethylzinc [(C 2 H 5 ) 2 Zn] as a precursor, ALD of ZnO on the surface activated MWCNTs was performed using an Arradiance Gemstar ALD tool (details can be found in Ref. 25).…”

Section: A Sensor Fabricationmentioning

confidence: 99%

“…Sensors were exposed to a 10 ppm mixture of CH 4 in synthetic air (20.81% of O 2 and 79.19% of N 2 ; prepared by Praxair Inc.). The flow rate was maintained at 0.94 l/min with a residence time of 4.5 min inside the plastic test chamber (details elsewhere 25 ). After the CH 4 exposure, the sensors were flushed with N 2 (the same flow rate as CH 4 , 0.94 l/min).…”

Section: Test Setup and Approachmentioning

confidence: 99%

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Effects of O2 plasma and UV-O3 assisted surface activation on high sensitivity metal oxide functionalized multiwalled carbon nanotube CH4 sensors

Humayun

Sainato

Divan

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The authors present a comparative analysis of ultraviolet-O 3 (UVO) and O 2 plasma-based surface activation processes of multiwalled carbon nanotubes (MWCNTs), enabling highly effective functionalization with metal oxide nanocrystals (MONCs). Experimental results from transmission electron microscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, and Raman spectroscopy show that by forming COOH (carboxyl), C-OH (hydroxyl), and C¼O (carbonyl) groups on the MWCNT surface that act as active nucleation sites, O 2 plasma and UVO-based dry pretreatment techniques greatly enhance the affinity between the MWCNT surface and the functionalizing MONCs. MONCs, such as ZnO and SnO 2 , deposited by the atomic layer deposition technique, were implemented as the functionalizing material following UVO and O 2 plasma activation of MWCNTs. A comparative study on the relative resistance changes of O 2 plasma and UVO activated MWCNT functionalized with MONC in the presence of 10 ppm methane (CH 4) in air is presented as well. V

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ZnO functionalization of multiwalled carbon nanotubes for methane sensing at single parts per million concentration levels

Abstract: Realizing room-temperature self-powered ethanol sensing of Au/ZnO nanowire arrays by coupling the piezotronics effect of ZnO and the catalysis of noble metal

Cited by 20 publications

References 21 publications

Carbon Nanotube Chemical Sensors

Carbon Nanotube Chemical Sensors

Investigation of ZnO-decorated CNTs for UV Light Detection Applications

Effects of O2 plasma and UV-O3 assisted surface activation on high sensitivity metal oxide functionalized multiwalled carbon nanotube CH4 sensors

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