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5 pages, 183 KiB

Open AccessEditorial

Special Issue “Advanced Nanomaterials Based Gas Sensors”

by Xavier Vilanova

Sensors 2020, 20(5), 1373; https://doi.org/10.3390/s20051373 - 2 Mar 2020

Cited by 2 | Viewed by 2662

Abstract

During the last several years, according to the works published in research journals, many nanostructured materials have been tested as sensing materials for gas-sensing applications. This trend has been observed for both metal oxides as well as carbon-based nanomaterials. More recently, it has [...] Read more.

During the last several years, according to the works published in research journals, many nanostructured materials have been tested as sensing materials for gas-sensing applications. This trend has been observed for both metal oxides as well as carbon-based nanomaterials. More recently, it has also been extended to other materials based on chalcogenides. The field of applications for these sensors is very wide, including air quality, industrial safety and medical diagnosis, using different transducing mechanisms. Therefore, in this Special Issue, we have put together recent advances in this area. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

Research

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17 pages, 4853 KiB

Open AccessArticle

Highly Sensitive Detection of NO₂ by Au and TiO₂ Nanoparticles Decorated SWCNTs Sensors

by Ada Fort, Enza Panzardi, Ammar Al-Hamry, Valerio Vignoli, Marco Mugnaini, Tommaso Addabbo and Olfa Kanoun

Sensors 2020, 20(1), 12; https://doi.org/10.3390/s20010012 - 18 Dec 2019

Cited by 23 | Viewed by 3969

Abstract

The aim of this work is to investigate the gas sensing performance of single wall carbon nanotubes (SWCNTs)-based conductive sensors operating at low–medium temperatures (<250 °C). The investigated sensing films consists of an SWCNT network obtained by drop-casting a SWCNT suspension. Starting from [...] Read more.

The aim of this work is to investigate the gas sensing performance of single wall carbon nanotubes (SWCNTs)-based conductive sensors operating at low–medium temperatures (<250 °C). The investigated sensing films consists of an SWCNT network obtained by drop-casting a SWCNT suspension. Starting from this base preparation, different sensing devices were obtained by decorating the SWCNT network with materials suitable for enhancing the sensitivity toward the target gas. In particular, in this paper, nano-particles of gold and of TiO₂ were used. In the paper, the performance of the different sensing devices, in terms of response time, sensitivity toward NO₂ and cross-sensitivity to O₂, CO and water vapor, were assessed and discussed. Sensors based on decorated SWCNT films showed high performance; in particular, the decoration with Au nano-particles allows for a large enhancement of sensitivity (reaching 10%/1 ppm at 240 °C) and a large reduction of response time. On the other hand, the addition of TiO₂ nanoparticles leads to a satisfactory improvement of the sensitivity as well as a significant reduction of the response time at moderate temperatures (down to 200 °C). Finally, the suitability of using Au decorated SWCNTs-based sensors for room temperature sensing is demonstrated. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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10 pages, 8860 KiB

Open AccessArticle

Enhanced Room Temperature NO₂ Sensing Performance of RGO Nanosheets by Building RGO/SnO₂ Nanocomposite System

by Hongfei Du, Guangzhong Xie and Qiuping Zhang

Sensors 2019, 19(21), 4650; https://doi.org/10.3390/s19214650 - 26 Oct 2019

Cited by 9 | Viewed by 2747

Abstract

RGO/SnO

_{2}

nanocomposites were prepared by a simple blending method and then airbrushed on interdigitated electrodes to obtain the corresponding gas sensors. The characterizations of SEM, TEM, Raman, XRD and FTIR were used to characterize the microstructures, morphologies and surface chemical compositions of [...] Read more.

RGO/SnO

_{2}

nanocomposites were prepared by a simple blending method and then airbrushed on interdigitated electrodes to obtain the corresponding gas sensors. The characterizations of SEM, TEM, Raman, XRD and FTIR were used to characterize the microstructures, morphologies and surface chemical compositions of the nanocomposites, indicating that the two materials coexist in the composite films and the concentration of surface defects is affected by the amount of SnO

_{2}

nanoparticles. It is also found that the room temperature sensing performance of RGO to NO

_{2}

can be improved by introducing appropriate amount of SnO

_{2}

nanoparticles. The enhanced NO

_{2}

sensing properties are attributed to the rough surface structure and increased surface area and surface defects of the nanocomposite films. Since further reduction of RGO, heat treating the sensing films resulted in a decrease in the response and recovery times of the sensors. Furthermore, the sensor annealed at 200

^{\circ}

C exhibited a small baseline drift, wide detection range, good linearity, high stability and better selectivity. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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22 pages, 5916 KiB

Open AccessArticle

Design and Fabrication of CMOS Microstructures to Locally Synthesize Carbon Nanotubes for Gas Sensing

by Avisek Roy, Mehdi Azadmehr, Bao Q. Ta, Philipp Häfliger and Knut E. Aasmundtveit

Sensors 2019, 19(19), 4340; https://doi.org/10.3390/s19194340 - 8 Oct 2019

Cited by 7 | Viewed by 3608

Abstract

Carbon nanotubes (CNTs) can be grown locally on custom-designed CMOS microstructures to use them as a sensing material for manufacturing low-cost gas sensors, where CMOS readout circuits are directly integrated. Such a local CNT synthesis process using thermal chemical vapor deposition (CVD) requires [...] Read more.

Carbon nanotubes (CNTs) can be grown locally on custom-designed CMOS microstructures to use them as a sensing material for manufacturing low-cost gas sensors, where CMOS readout circuits are directly integrated. Such a local CNT synthesis process using thermal chemical vapor deposition (CVD) requires temperatures near 900 °C, which is destructive for CMOS circuits. Therefore, it is necessary to ensure a high thermal gradient around the CNT growth structures to maintain CMOS-compatible temperature (below 300 °C) on the bulk part of the chip, where readout circuits are placed. This paper presents several promising designs of CNT growth microstructures and their thermomechanical analyses (by ANSYS Multiphysics software) to check the feasibility of local CNT synthesis in CMOS. Standard CMOS processes have several conductive interconnecting metal and polysilicon layers, both being suitable to serve as microheaters for local resistive heating to achieve the CNT growth temperature. Most of these microheaters need to be partially or fully suspended to produce the required thermal isolation for CMOS compatibility. Necessary CMOS post-processing steps to realize CNT growth structures are discussed. Layout designs of the microstructures, along with some of the microstructures fabricated in a standard AMS 350 nm CMOS process, are also presented in this paper. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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15 pages, 4447 KiB

Open AccessArticle

A Separated Receptor/Transducer Scheme as Strategy to Enhance the Gas Sensing Performance Using Hematite–Carbon Nanotube Composite

by Nguyen Minh Hieu, Cao Van Phuoc, Truong Thi Hien, Nguyen Duc Chinh, Nguyen Duc Quang, Chunjoong Kim, Jong-Ryul Jeong and Dojin Kim

Sensors 2019, 19(18), 3915; https://doi.org/10.3390/s19183915 - 11 Sep 2019

Cited by 12 | Viewed by 3388

Abstract

Nanocomposite structures, where the Fe, Fe₂O₃, or Ni₂O₃ nanoparticles with thin carbon layers are distributed among a single-wall carbon nanotube (SWCNT) network, are architectured using the co-arc discharge method. A synergistic effect between the nanoparticles and [...] Read more.

Nanocomposite structures, where the Fe, Fe₂O₃, or Ni₂O₃ nanoparticles with thin carbon layers are distributed among a single-wall carbon nanotube (SWCNT) network, are architectured using the co-arc discharge method. A synergistic effect between the nanoparticles and SWCNT is achieved with the composite structures, leading to the enhanced sensing response in ammonia detection. Thorough studies about the correlation between the electric properties and sensing performance confirm the independent operation of the receptor and transducer in the sensor structure by nanoparticles and SWCNT, respectively. Nanoparticles with a large specific surface area provide adsorption sites for the NH₃ gas molecules, whereas hole carriers are supplied by the SWCNT to complete the chemisorption process. A new chemo-resistive sensor concept and its operating mechanism is proposed in our work. Furthermore, the separated receptor and transducer sensor scheme allows us more freedom in the design of sensor materials and structures, thereby enabling the design of high-performance gas sensors. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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11 pages, 2482 KiB

Open AccessArticle

Cu/CuO@ZnO Hollow Nanofiber Gas Sensor: Effect of Hollow Nanofiber Structure and P–N Junction on Operating Temperature and Sensitivity

by Sung-Ho Hwang, Young Kwang Kim, Seong Hui Hong and Sang Kyoo Lim

Sensors 2019, 19(14), 3151; https://doi.org/10.3390/s19143151 - 17 Jul 2019

Cited by 17 | Viewed by 3802

Abstract

For the fast and easy detection of carbon monoxide (CO) gas, it was necessary to develop a CO gas sensor to operate in low temperatures. Herein, a novel Cu/CuO-decorated ZnO hollow nanofiber was prepared with the electrospinning, calcination, and photodeposition methods. In the [...] Read more.

For the fast and easy detection of carbon monoxide (CO) gas, it was necessary to develop a CO gas sensor to operate in low temperatures. Herein, a novel Cu/CuO-decorated ZnO hollow nanofiber was prepared with the electrospinning, calcination, and photodeposition methods. In the presence of 100 ppm CO gas, the Cu/CuO-photodeposited ZnO hollow nanofiber (Cu/CuO@ZnO HNF) showed twice higher sensitivity than that of pure ZnO nanofiber at a relatively low working temperature of 300 °C. The hollow structure and p–n junction between Cu/CuO and ZnO would be considered to contribute to the enhancement of sensitivity to CO gas at 300 °C due to the improved specific surface area and efficient electron transfer. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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15 pages, 3128 KiB

Open AccessArticle

Conductometric Sensing with Individual InAs Nanowires

by Valeria Demontis, Mirko Rocci, Maurizio Donarelli, Rishi Maiti, Valentina Zannier, Fabio Beltram, Lucia Sorba, Stefano Roddaro, Francesco Rossella and Camilla Baratto

Sensors 2019, 19(13), 2994; https://doi.org/10.3390/s19132994 - 7 Jul 2019

Cited by 23 | Viewed by 4572

Abstract

In this work, we isolate individual wurtzite InAs nanowires and fabricate electrical contacts at both ends, exploiting the single nanostructures as building blocks to realize two different architectures of conductometric sensors: (a) the nanowire is drop-casted onto—supported by—a SiO₂/Si substrate, and [...] Read more.

In this work, we isolate individual wurtzite InAs nanowires and fabricate electrical contacts at both ends, exploiting the single nanostructures as building blocks to realize two different architectures of conductometric sensors: (a) the nanowire is drop-casted onto—supported by—a SiO₂/Si substrate, and (b) the nanowire is suspended at approximately 250 nm from the substrate. We test the source-drain current upon changes in the concentration of humidity, ethanol, and NO₂, using synthetic air as a gas carrier, moving a step forward towards mimicking operational environmental conditions. The supported architecture shows higher response in the mid humidity range (50% relative humidity), with shorter response and recovery times and lower detection limit with respect to the suspended nanowire. These experimental pieces of evidence indicate a minor role of the InAs/SiO₂ contact area; hence, there is no need for suspended nanostructures to improve the sensing performance. Moreover, the sensing capability of single InAs nanowires for detection of NO₂ and ethanol in the ambient atmosphere is reported and discussed. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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14 pages, 8272 KiB

Open AccessArticle

Highly Selective, ppb-Level Xylene Gas Detection by Sn²⁺-Doped NiO Flower-Like Microspheres Prepared by a One-Step Hydrothermal Method

by Shaohe Lu, Xuefeng Hu, Hua Zheng, Junwen Qiu, Renbing Tian, Wenjing Quan, Xinjie Min, Peng Ji, Yewei Hu, Suishi Cheng, Wei Du, Xiaoqiang Chen, Beiliang Cui, Xiaorong Wang and Wei Zhang

Sensors 2019, 19(13), 2958; https://doi.org/10.3390/s19132958 - 4 Jul 2019

Cited by 22 | Viewed by 4027

Abstract

Detecting xylene gas is an important means of avoiding human harm from gas poisoning. A precise measurement demands that the gas sensor used must have high sensitivity, high selectivity, and low working temperature. To meet these requirements, in this study, Sn²⁺-doped [...] Read more.

Detecting xylene gas is an important means of avoiding human harm from gas poisoning. A precise measurement demands that the gas sensor used must have high sensitivity, high selectivity, and low working temperature. To meet these requirements, in this study, Sn²⁺-doped NiO flower-like microspheres (SNM) with different amounts of Sn²⁺ synthesized by a one-step hydrothermal process were investigated. The responses of gas sensors based on different Sn²⁺-doped NiO materials for various targeting gases were fully characterized. It was found that all of the synthesized materials exhibited the best gas response at a working temperature of 180 degrees, which was much lower than the previously reported working temperature range of 300–500 degrees. When exposed to 10 ppm xylene, the 8 at% Sn²⁺-doped NiO sensor (mol ratio) exhibited the highest response, with a value of 30 (R_g/R_a). More significantly, the detection limit of the 8 at% Sn²⁺-doped NiO sensor for xylene is down in the ppb level. The Sn²⁺-doped NiO material also exhibits excellent selectivity for other gases with long-term stability and repeatability. The significant improvement in the response to xylene can theoretically be attributed to a decrease in the intrinsic hole carrier concentration, higher amounts of adsorbed oxygen and active sites. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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7 pages, 2362 KiB

Open AccessArticle

An Ethanol Vapor Sensor Based on a Microfiber with a Quantum-Dot Gel Coating

by Siqi Hu, Guofeng Yan, Chunzhou Wu and Sailing He

Sensors 2019, 19(2), 300; https://doi.org/10.3390/s19020300 - 14 Jan 2019

Cited by 10 | Viewed by 4430

Abstract

An ethanol vapor sensor based on a microfiber with a quantum-dot (QD) gel coating is proposed and demonstrated. The QD gel was made from UV glue as the gel matrix and CdSe/ZnS QDs with a concentration of 1 mg/mL. The drawing and coating [...] Read more.

An ethanol vapor sensor based on a microfiber with a quantum-dot (QD) gel coating is proposed and demonstrated. The QD gel was made from UV glue as the gel matrix and CdSe/ZnS QDs with a concentration of 1 mg/mL. The drawing and coating processes were conducted by using a simple and low-cost system developed for this study. Bending, ethanol sensing, temperature response, and time response tests were carried out, respectively. The experimental results showed that the fabricated sensor had a high sensitivity of −3.3%/ppm, a very low temperature cross-sensitivity of 0.17 ppm/°C, and a fast response time of 1.1 s. The easily fabricated robust structure and the excellent sensing performance render the sensor a promising platform for real ethanol sensing applications. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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11 pages, 2414 KiB

Open AccessArticle

A Room-Temperature CNT/Fe₃O₄ Based Passive Wireless Gas Sensor

by Tao Guo, Tianhao Zhou, Qiulin Tan, Qianqian Guo, Fengxiang Lu and Jijun Xiong

Sensors 2018, 18(10), 3542; https://doi.org/10.3390/s18103542 - 19 Oct 2018

Cited by 17 | Viewed by 4829

Abstract

A carbon nanotube/Fe₃O₄ thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe₃O₄ as a gas [...] Read more.

A carbon nanotube/Fe₃O₄ thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe₃O₄ as a gas sensing material is explained. The design and fabrication process of the sensor and the testing method are introduced. Experimental results reveal that the proposed carbon nanotube (CNT)/Fe₃O₄ based sensor performs well on sensing ammonia (NH₃) at room temperature. The sensor exhibits not only an excellent response, good selectivity, and fast response and recovery times at room temperature, but is also characterized by good repeatability and low cost. The results for the wireless gas sensor’s performance for different NH₃ gas concentrations are presented. The developed device is promising for the establishment of wireless gas sensors in harsh environments. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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12 pages, 4094 KiB

Open AccessArticle

Enhanced Gas-Sensing Performance of GO/TiO₂ Composite by Photocatalysis

by Eunji Lee, Doohee Lee, Jaesik Yoon, Yilin Yin, You Na Lee, Sunil Uprety, Young Soo Yoon and Dong-Joo Kim

Sensors 2018, 18(10), 3334; https://doi.org/10.3390/s18103334 - 5 Oct 2018

Cited by 34 | Viewed by 6289

Abstract

Few studies have investigated the gas-sensing properties of graphene oxide/titanium dioxide (GO/TiO₂) composite combined with photocatalytic effect. Room temperature gas-sensing properties of the GO/TiO₂ composite were investigated towards various reducing gases. The composite sensor showed an enhanced gas response and [...] Read more.

Few studies have investigated the gas-sensing properties of graphene oxide/titanium dioxide (GO/TiO₂) composite combined with photocatalytic effect. Room temperature gas-sensing properties of the GO/TiO₂ composite were investigated towards various reducing gases. The composite sensor showed an enhanced gas response and a faster recovery time than a pure GO sensor due to the synergistic effect of the hybridization, such as creation of a hetero-junction at the interface and modulation of charge carrier density. However, the issue of long-term stability at room temperature still remains unsolved even after construction of a composite structure. To address this issue, the surface and hetero-junction of the GO/TiO₂ composite were engineered via a UV process. A photocatalytic effect of TiO₂ induced the reduction of the GO phase in the composite solution. The comparison of gas-sensing properties before and after the UV process clearly showed the transition from n-type to p-type gas-sensing behavior toward reducing gases. This transition revealed that the dominant sensing material is GO, and TiO₂ enhanced the gas reaction by providing more reactive sites. With a UV-treated composite sensor, the function of identifying target gas was maintained over a one-month period, showing strong resistance to humidity. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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17 pages, 3305 KiB

Open AccessArticle

Water-Based Indium Tin Oxide Nanoparticle Ink for Printed Toluene Vapours Sensor Operating at Room Temperature

by Jan Maslik, Ivo Kuritka, Pavel Urbanek, Petr Krcmar, Pavol Suly, Milan Masar and Michal Machovsky

Sensors 2018, 18(10), 3246; https://doi.org/10.3390/s18103246 - 27 Sep 2018

Cited by 18 | Viewed by 4712

Abstract

This study is focused on the development of water-based ITO nanoparticle dispersions and ink-jet fabrication methodology of an indium tin oxide (ITO) sensor for room temperature operations. Dimensionless correlations of material-tool-process variables were used to map the printing process and several interpretational frameworks [...] Read more.

This study is focused on the development of water-based ITO nanoparticle dispersions and ink-jet fabrication methodology of an indium tin oxide (ITO) sensor for room temperature operations. Dimensionless correlations of material-tool-process variables were used to map the printing process and several interpretational frameworks were re-examined. A reduction of the problem to the Newtonian fluid approach was applied for the sake of simplicity. The ink properties as well as the properties of the deposited layers were tested for various nanoparticles loading. High-quality films were prepared and annealed at different temperatures. The best performing material composition, process parameters and post-print treatment conditions were used for preparing the testing sensor devices. Printed specimens were exposed to toluene vapours at room temperature. Good sensitivity, fast responses and recoveries were observed in ambient air although the n-type response mechanism to toluene is influenced by moisture in air and baseline drift was observed. Sensing response inversion was observed in an oxygen and moisture-free N₂ atmosphere which is explained by the charge-transfer mechanism between the adsorbent and adsorbate molecules. The sensitivity of the device was slightly better and the response was stable showing no drifts in the protective atmosphere. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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12 pages, 6469 KiB

Open AccessArticle

A Gas Sensor Based on a Single SnO Micro-Disk

by Mateus G. Masteghin and Marcelo O. Orlandi

Sensors 2018, 18(10), 3229; https://doi.org/10.3390/s18103229 - 25 Sep 2018

Cited by 19 | Viewed by 3918

Abstract

In this study, individual nanofabricated SnO micro-disks, previously shown to exhibit exceptional sensitivity to NO_x, are investigated to further our understanding of gas sensing mechanisms. The SnO disks presenting different areas and thickness were isolated and electrically connected to metallic electrodes [...] Read more.

In this study, individual nanofabricated SnO micro-disks, previously shown to exhibit exceptional sensitivity to NO_x, are investigated to further our understanding of gas sensing mechanisms. The SnO disks presenting different areas and thickness were isolated and electrically connected to metallic electrodes aided by a Dual Beam Microscope (SEM/FIB). While single micro-disk devices were found to exhibit short response and recovery times and low power consumption, large interconnected arrays of micro-disks exhibit much higher sensitivity and selectivity. The source of these differences is discussed based on the gas/solid interaction and transport mechanisms, which showed that thickness plays a major role during the gas sensing of single-devices. The calculated Debye length of the SnO disk in presence of NO₂ is reported for the first time. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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15 pages, 6856 KiB

Open AccessArticle

Development of Organic-Inorganic Hybrid Optical Gas Sensors for the Non-Invasive Monitoring of Pathogenic Bacteria

by Sumana Kladsomboon, Chadinee Thippakorn and Thara Seesaard

Sensors 2018, 18(10), 3189; https://doi.org/10.3390/s18103189 - 21 Sep 2018

Cited by 22 | Viewed by 6687

Abstract

Hybrid optical gas sensors, based on different organic and inorganic materials, are proposed in this paper, with the aim of using them as optical artificial nose systems. Three types of organic and inorganic dyes, namely zinc-porphyrin, manganese-porphyrin, and zinc-phthalocyanine, were used as gas [...] Read more.

Hybrid optical gas sensors, based on different organic and inorganic materials, are proposed in this paper, with the aim of using them as optical artificial nose systems. Three types of organic and inorganic dyes, namely zinc-porphyrin, manganese-porphyrin, and zinc-phthalocyanine, were used as gas sensing materials to fabricate a thin-film coating on glass substrates. The performance of the gas sensor was enhanced by a thermal treatment process. The optical absorption spectra and morphological structure of the sensing films were confirmed by UV-Vis spectrophotometer and atomic force microscope, respectively. The optical gas sensors were tested with various volatile compounds, such as acetic acid, acetone, ammonia, ethanol, ethyl acetate, and formaldehyde, which are commonly found to be released during the growth of bacteria. These sensors were used to detect and discriminate between the bacterial odors of three pathogenic species (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) grown in Luria-Bertani medium. Based on a pattern recognition (PARC) technique, we showed that the proposed hybrid optical gas sensors can discriminate among the three pathogenic bacterial odors and that the volatile organic compound (VOC) odor pattern of each bacterium was dependent on the phase of bacterial growth. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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11 pages, 5152 KiB

Open AccessArticle

A Room Temperature VOCs Gas Sensor Based on a Layer by Layer Multi-Walled Carbon Nanotubes/Poly-ethylene Glycol Composite

by Zitao Liu, Tuoyu Yang, Ying Dong and Xiaohao Wang

Sensors 2018, 18(9), 3113; https://doi.org/10.3390/s18093113 - 15 Sep 2018

Cited by 46 | Viewed by 7185

Abstract

Sensitive detection of volatile organic compounds (VOCs) is significant for environmental monitoring and medical applications. In this work, multi-walled carbon nanotubes (MWCNTs) and polyethylene glycol (PEG) that have good adsorption for VOCs, were sprayed layer by layer on an interdigitated electrode (IDE) to [...] Read more.

Sensitive detection of volatile organic compounds (VOCs) is significant for environmental monitoring and medical applications. In this work, multi-walled carbon nanotubes (MWCNTs) and polyethylene glycol (PEG) that have good adsorption for VOCs, were sprayed layer by layer on an interdigitated electrode (IDE) to build a sensitive VOCs gas sensor. The relative resistance change (△R/R) when the sensor was exposed to VOCs was measured. The sensor showed high sensitivity to acetone, ethanol, isopropanol and isoprene with fast response (110 ± 5 s) and recovery (152 ± 5 s) at room temperature, and the lower detection limit (LDL) of the sensor reached 9 ppm. With the micro-fabricated IDE structure, the sensor can be easily built into an electric nose for VOC recognition and measurement. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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12 pages, 7315 KiB

Open AccessArticle

Highly Sensitive Acetone Gas Sensor Based on g-C₃N₄ Decorated MgFe₂O₄ Porous Microspheres Composites

by Run Zhang, Yan Wang, Zhanying Zhang and Jianliang Cao

Sensors 2018, 18(7), 2211; https://doi.org/10.3390/s18072211 - 10 Jul 2018

Cited by 59 | Viewed by 6249

Abstract

The g-C₃N₄ decorated magnesium ferrite (MgFe₂O₄) porous microspheres composites were successfully obtained via a one-step solvothermal method. The structure and morphology of the as-prepared MgFe₂O₄/g-C₃N₄ composites were characterized by [...] Read more.

The g-C₃N₄ decorated magnesium ferrite (MgFe₂O₄) porous microspheres composites were successfully obtained via a one-step solvothermal method. The structure and morphology of the as-prepared MgFe₂O₄/g-C₃N₄ composites were characterized by the techniques of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermal gravity and differential scanning calorimeter (TG–DSC) and N₂-sorption. The gas sensing properties of the samples were measured and compared with a pure MgFe₂O₄-based sensor. The maximum response of the sensor based on MgFe₂O₄/g-C₃N₄ composites with 10 wt % g-C₃N₄ content to acetone is improved by about 145 times, while the optimum temperature was lowered by 60 °C. Moreover, the sensing mechanism and the reason for improving gas sensing performance were also discussed. Full article

(This article belongs to the Special Issue Advanced Nanomaterials based Gas Sensors)

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