Metal Functionalised Carbon Nanotubes Thin Films Gas Chemiresistors

Penza, M.; Cassano, G.; Rossi, Riccardo; Alvisi, Marco; Signore, M.A.; Rizzo, Alex; Dikonimos, Theodoros; Lisi, N.; Salernitano, E.; Serra, Emanuele; Giorgi, R.

doi:10.1142/9789812833594_0026

Cited by 9 publications

(10 citation statements)

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“…This reveals that not only the direct charge transfer between gas and CNTs but also the modulation in conduction path due to analyte‐specific swelling behaviors can be utilized to control the gas selectivity in CNT‐based gas sensors as well as to design electronic noses using composites of CNT and organic material. Finally, gas sensing behaviors of CNT‐based sensors can also be modified by loading noble metal catalysts such as Pt, [ 477,478 ] Au, [ 477,479,480 ] and Pd [ 478 ] or by decorating with metal oxide semiconductors such as SnO 2 , [ 481 ] ZnO, [ 482 ] Fe 2 O 3 , [ 483 ] CuO, [ 484 ] and Co 3 O 4 . [ 485 ]…”

Section: Emerging Sensing Materials For Artificial Olfactionmentioning

confidence: 99%

Rational Design of Semiconductor‐Based Chemiresistors and their Libraries for Next‐Generation Artificial Olfaction

2020

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With rapid progress in device integration and computing power, the realization of highly miniaturized one-chip artificial olfaction with superior performance is close and should be further supported by the rational design of chemical sensors and chemical sensing materials. The number of gas sensors tends to increase in order to sniff more complex odors with the progress of civilization. This explains the evolution from a single chemical sensor to complicated artificial olfaction using sensor arrays. At the advent of oxide chemiresistive gas sensors in the 1960s and 1970s, a single gas sensor was widely used to detect toxic, explosive, dangerous, and harmful gases, such as CO, C 3 H 8 , CH 4 , H 2 S, and NO 2 , in a selective manner. [26,27] However, a single sensor is often insufficient for recognizing most of the natural odors encountered in daily life, which consist of hundreds to thousands of different chemicals. [28] In the mammalian olfactory system, odorants are initially detected by olfactory receptors (ORs) covering the surface of the cilia projected from olfactory sensory neurons (OSNs), which are located in the olfactory epithelium lining the nasal cavity. These signals are transmitted to the glomeruli in the olfactory bulb, where a high degree of signal integration happens (Figure 1a). [29] Finally, the signals are sent through mitral cells to a higher brain region (olfactory cortex), and the signals are subsequently combined or modified in a variety of ways by parallel processing for analysis and interpretation (Figure 1b). [30] Each OR can detect various kinds of odorants, and similarly, each odorant can also be recognized by a number of ORs. That is, the olfactory system determines multiple odorants from various combinations of ORs (Figure 1c). [31] For better olfaction, both OSNs and ORs should be abundant. A larger number of OSNs is advantageous for detecting trace concentrations of analytes and ligands. [32] For instance, dogs with more OSNs are better than humans at detecting explosives, searching and rescuing, diagnosing disease, and assessing agricultural products. [33] If a mammal can detect larger numbers of faint gas components within odors, he can perceive and identify the odors more accurately. From this perspective, gas sensors with lower detection limits would be assembled to the stronger artificial olfaction. Kinds of ORs are also important. Mammals are known to have ≈1000 different kinds of ORs, and combinations of dissimilar ORs enable the discrimination of a myriad of odorants. [29] To mimic this, sensor arrays consisting of small number (5-20) of sensors that show Artificial olfaction based on gas sensor arrays aims to substitute for, support, and surpass human olfaction. Like mammalian olfaction, a larger number of sensors and more signal processing are crucial for strengthening artificial olfaction. Due to rapid progress in computing capabilities and machinelearning algorithms, on-demand high-performance artificial olfaction that can eclipse human olfaction becomes inevitable onc...

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Section: Emerging Sensing Materials For Artificial Olfactionmentioning

confidence: 99%

Rational Design of Semiconductor‐Based Chemiresistors and their Libraries for Next‐Generation Artificial Olfaction

2020

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“…Therefore, detection of the NO 2 below the risk range is absolutely crucial. Most studies on the enhanced NO 2 gas‐sensing performance have focused on the combining polymer functionalization or metal nanoparticle decoration with CNTs . The CNTs functionalized polymer and decorated metal nanoparticle show high sensitivity to NO 2 .…”

Section: Introductionmentioning

confidence: 99%

Unravel the Active Site in Nitrogen‐Doped Double‐Walled Carbon Nanotubes for Nitrogen Dioxide Gas Sensor

Muangrat

Wongwiriyapan

Yordsri

et al. 2018

Physica Status Solidi (a)

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In this paper, a nitrogen dioxide (NO 2 ) gas sensor using nitrogen-doped double-walled carbon nanotubes (N-DWCNTs) with different types of nitrogen is demonstrated, and the sensor performance to the pyridinic nitrogen is related. The ratio of nitrogen is controlled by the temperature applied for the synthesis. It is found that the fabricated sensor from N-DWCNTs enable an approximately threefold improvement in NO 2 detection compared to the sensor from DWCNTs. Also, the improvement of sensor response of N-DWCNTs more depends on the pyridinic site than the other types of nitrogen, because it can strongly interact with the NO 2 molecule. The sensing mechanism is attributed to the charge transfer between the NO 2 molecule and the sensing materials (especially with pyridinic site), which shifts the Fermi level, resulting in a decrease of the electrical resistance. Furthermore, the relation between the sensor response and the concentration of NO 2 is derived based on Langmuir adsorption isotherm, and the calculated detection limit can be down to 0.14 ppm, which suggests that the N-DWCNTs-based sensor is a promising approach for low concentration NO 2 detection at room temperature.

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“…MWCNT networked films were grown by chemical vapor deposition (CVD) directly onto the surface of an alumina substrate that was previously coated with a cobalt (Co) sputtered catalytic layer (≈6 nm thick), as previously reported [ 32 ].…”

Section: Methodsmentioning

confidence: 99%

Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles

Dilonardo¹,

Penza²,

Alvisi³

et al. 2017

Beilstein J. Nanotechnol.

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Multiwalled carbon nanotube (MWCNT)-based chemiresistors were electrochemically decorated with Au and Pd nanoparticles (NPs), resulting in an improvement in the detection of gaseous pollutants as compared to sensors based on pristine MWCNTs. Electrophoresis was used to decorate MWCNTs with preformed Au or Pd NPs, thus preserving their nanometer-sized dimensions and allowing the metal content to be tuned by simply varying the deposition time. The sensing response of unmodified and metal-decorated MWCNTs was evaluated towards different gaseous pollutants (e.g., NO2, H2S, NH3 and C4H10) at a wide range of concentrations in the operating temperature range of 45–200 °C. The gas sensing results were related to the presence, type and loading of metal NPs used in the MWCNT functionalization. Compared to pristine MWCNTs, metal-decorated MWCNTs revealed a higher gas sensitivity, a faster response, a better stability, reversibility and repeatability, and a low detection limit, where all of these sensing properties were controlled by the type and loading of the deposited metal catalytic NPs. Specifically, in the NO2 gas sensing experiments, MWCNTs decorated with the lowest Au content revealed the highest sensitivity at 150 °C, while MWCNTs with the highest Pd loading showed the highest sensitivity when operated at 100 °C. Finally, considering the reported gas sensing results, sensing mechanisms have been proposed, correlating the chemical composition and gas sensing responses.

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Metal Functionalised Carbon Nanotubes Thin Films Gas Chemiresistors

Cited by 9 publications

References 0 publications

Rational Design of Semiconductor‐Based Chemiresistors and their Libraries for Next‐Generation Artificial Olfaction

Rational Design of Semiconductor‐Based Chemiresistors and their Libraries for Next‐Generation Artificial Olfaction

Unravel the Active Site in Nitrogen‐Doped Double‐Walled Carbon Nanotubes for Nitrogen Dioxide Gas Sensor

Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles

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