High-Sensitivity and -Selectivity Gas Sensors with Nanoparticles, Nanostructures, and Thin Films

A special issue of Chemosensors (ISSN 2227-9040). This special issue belongs to the section "Nanostructures for Chemical Sensing".

Deadline for manuscript submissions: closed (25 June 2022) | Viewed by 34368

Special Issue Editors


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Department of High-Temperature and Functional Coatings, Institute of Materials Research, German Aerospace Center (DLR), 51147 Cologne, Germany
Interests: gas sensors; nanostructures; semiconducting oxides; supercapacitors; batteries; catalysts, functional coatings and electrolytes
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Guest Editor
Higher Teacher Training College, University of Yaounde I, Yaounde P.O. BOX 47, Cameroon
Interests: metal oxide gas sensor; wet chemistry synthesis; thin film deposition; materials chemistry

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Guest Editor
Department of High-Temperature and Functional Coatings, Institute of Materials Research, German Aerospace Center (DLR), 51147 Cologne, Germany
Interests: batteries; nanostructured oxides; gas sensors; catalysts; materials; cathode materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Advanced gas sensors fabricated with nanoparticles and thin films of semiconductor metal oxides have been widely used for the detection of toxic, hazardous, combustible gases and biomakers for the safety of human beings, environmental control, and breath analysis. This is certainly due to their advantages such as the simplicity of their synthesis, their high sensitivity to small concentrations of gases, their low fabrication cost, and their long-term stability. Despite these advantages, their selectivity and cross-sensitivity remain challenging issues. A barrier for the implementation of semiconductor metal oxides is their slow kinetics both in response to target analytes and recovery. Recent progress in the synthesis of novel nanostructures reveals that these issues can be overcome by the achievement of superior surface area, pore size and distribution, control of the morphology, by doping (in order to promote the reaction to specific gases), and the use of composites, heterostructures of metal oxides, etc.

The goal of this Special Issue is to highlight new achievements on the improvement of gas sensor performance by doping, and the synthesis of nanoparticles and thin films in various morphologies, heterostructures, and nanocomposites. Original research works and reviews are welcome on topics of interest including but not limited to the following:

  • Effects of Nanoparticles, nanostructures, and thin-films;
  • Nanocomposites, heterostructures;
  • p-n and n-n junctions;
  • Doping and decoration of metal oxides;
  • Synthesis in various morphology and compositions;
  • On gas sensing and detection;
  • For applications in e-nose, breath analysis, indoor and environmental pollutin, combustion and burning condition monitoring.

Dr. Bilge Saruhan-Brings
Dr. Roussin Lontio Fomekong
Dr. Svitlana Nahirniak
Guest Editors

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Keywords

  • metal oxides
  • semiconductors
  • nanostructures
  • nanoparticles
  • thin films
  • doping
  • nanoscale heterojunctions
  • gas sensors
  • chemical gas sensing

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Published Papers (11 papers)

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Editorial

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3 pages, 192 KiB  
Editorial
High-Sensitivity and -Selectivity Gas Sensors with Nanoparticles, Nanostructures, and Thin Films
by Bilge Saruhan, Roussin Lontio Fomekong and Svitlana Nahirniak
Chemosensors 2023, 11(2), 81; https://doi.org/10.3390/chemosensors11020081 - 21 Jan 2023
Cited by 2 | Viewed by 1769
Abstract
Advanced gas sensors fabricated with nanoparticles and thin films of semiconductor metal oxides have been widely used for the detection of toxic, hazardous, and combustible gases and as biomarkers for the safety of human beings, environmental control, and breath analysis [...] Full article

Research

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10 pages, 1779 KiB  
Article
Self-Assembly of Ultrathin Nickel Oxysulfide for Reversible Gas Sensing at Room Temperature
by Nam Ha, Kai Xu, Yinfen Cheng, Rui Ou, Qijie Ma, Yihong Hu, Vien Trinh, Guanghui Ren, Hao Yu, Lei Zhang, Xiang Liu, Jiaru Zhang, Zhong Li and Jian Zhen Ou
Chemosensors 2022, 10(9), 372; https://doi.org/10.3390/chemosensors10090372 - 17 Sep 2022
Cited by 9 | Viewed by 2335
Abstract
Two-dimensional (2D) or ultrathin metal sulfides have been emerging candidates in developing high-performance gas sensors given their physisorption-dominated interaction with target gas molecules. Their oxysulfide derivatives, as intermediates between oxides and sulfides, were recently demonstrated to have fully reversible responses at room temperature [...] Read more.
Two-dimensional (2D) or ultrathin metal sulfides have been emerging candidates in developing high-performance gas sensors given their physisorption-dominated interaction with target gas molecules. Their oxysulfide derivatives, as intermediates between oxides and sulfides, were recently demonstrated to have fully reversible responses at room temperature and long-term device stability. In this work, we explored the micro-scale self-assembly of ultrathin nickel oxysulfide through the calcination of nickel sulfide in a controllable air environment. The thermal treatment resulted in the replacement of most S atoms in the Ni-S frameworks by O atoms, leading to the crystal phase transition from original hexagonal to orthorhombic coordination. In addition, the corresponding bandgap was slightly expanded by ~0.15 eV compared to that of pure nickel sulfide. Nickel oxysulfide exhibited a fully reversible response towards H2 at room temperature for concentrations ranging from 0.25% and 1%, without the implementation of external stimuli such as light excitation and voltage biasing. The maximum response factor of ~3.24% was obtained at 1% H2, which is at least one order larger than those of common industrial gases including CH4, CO2, and NO2. Such an impressive response was also highly stable for at least four consecutive cycles. This work further demonstrates the great potential of metal oxysulfides in room-temperature gas sensing. Full article
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18 pages, 9181 KiB  
Article
Semiconductor-Type Gas Sensors Based on γ-Fe2O3 Nanoparticles and Its Derivatives in Conjunction with SnO2 and Graphene
by Qi Qin, Diyor Olimov and Li Yin
Chemosensors 2022, 10(7), 267; https://doi.org/10.3390/chemosensors10070267 - 8 Jul 2022
Cited by 10 | Viewed by 2506
Abstract
The gas sensitivity of semiconductor metal oxides, such as γ-Fe2O3 and SnO2, is investigated together with the synergistic effects in conjunction with grapheme. Nanoparticles of γ-Fe2O3, γ-Fe2O3/SnO2, and [...] Read more.
The gas sensitivity of semiconductor metal oxides, such as γ-Fe2O3 and SnO2, is investigated together with the synergistic effects in conjunction with grapheme. Nanoparticles of γ-Fe2O3, γ-Fe2O3/SnO2, and γ-Fe2O3/SnO2/RGO, prepared by two-step fabrication, were assembled in gas-sensing devices to assess their sensitivities; response and recovery times for the detection of ethanol, methanol, isopropanol, formaldehyde, H2S, CO, and NO gases at different temperatures but constant concentrations of 100 particles per million (ppm); and H2S, which underwent the dynamic gas sensitivity test in different concentrations. Each sample’s crystallinity and microscopic morphology was investigated with X-ray diffraction and a scanning electron microscope. In comparative gas sensitivity measurements, the ternary composite of γ-Fe2O3/SnO2/RGO was identified as an ideal candidate, as it responds to all four tested liquids in the gas phase as well as H2S with a response value equal to 162.6. Further, only the ternary composite γ-Fe2O3/SnO2/RGO hybrid nanoparticles responded to NO gas with a sensor response value equal to 4.09 in 12 s. However, only the binary composite γ-Fe2O3/SnO2 responded to CO with a corresponding sensitivity of 1.59 units in 7 s. Full article
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13 pages, 3627 KiB  
Article
Preparation of Au@ZnO Nanofilms by Combining Magnetron Sputtering and Post-Annealing for Selective Detection of Isopropanol
by Guodong Wang, Pengju Wu, Lanlan Guo, Wei Wang, Wenqiang Liu, Yuanyuan Wang, Tingyu Chen, Haohan Wang, Yonghao Xu and Yingli Yang
Chemosensors 2022, 10(6), 211; https://doi.org/10.3390/chemosensors10060211 - 3 Jun 2022
Cited by 12 | Viewed by 2149
Abstract
We demonstrate the highly sensitive and fast response/recovery gas sensors for detecting isopropanol (IPA), in which the Au-nanoparticles-modified ZnO (Au@ZnO) nanofilms act as the active layers. The data confirm that both the response and the response/recovery speed for the detection of IPA are [...] Read more.
We demonstrate the highly sensitive and fast response/recovery gas sensors for detecting isopropanol (IPA), in which the Au-nanoparticles-modified ZnO (Au@ZnO) nanofilms act as the active layers. The data confirm that both the response and the response/recovery speed for the detection of IPA are significantly improved by adding Au nanoparticles on the surface of ZnO nanofilms. The gas sensor with an Optimum Au@ZnO nanofilm exhibits the highest responses of 160 and 7 to the 100 and 1 ppm IPA at 300 °C, which indicates high sensitivity and a very low detecting limit. The sensor also exhibits a very short response/recovery time of 4/15 s on the optimized Au@ZnO nanofilm, which is much shorter than that of the sensor with a pure ZnO nanofilm. The mechanisms of the performance improvement in the sensors are discussed in detail. Both the electronic sensitization and the chemical sensitization of the ZnO nanofilms are improved by the modified Au nanoparticles, which not only regulate the thickness of the depletion layer but also increase the amount of adsorbed oxygen species on the surfaces. This work proposes a strategy to develop a highly sensitive gas sensor for real-time monitoring of IPA. Full article
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14 pages, 4067 KiB  
Article
Semiquantitative Classification of Two Oxidizing Gases with Graphene-Based Gas Sensors
by Martin Lind, Valter Kiisk, Margus Kodu, Tauno Kahro, Indrek Renge, Tea Avarmaa, Prashanth Makaram, Amaia Zurutuza and Raivo Jaaniso
Chemosensors 2022, 10(2), 68; https://doi.org/10.3390/chemosensors10020068 - 8 Feb 2022
Cited by 9 | Viewed by 3049
Abstract
Miniature and low-power gas sensing elements are urgently needed for a portable electronic nose, especially for outdoor pollution monitoring. Hereby we prepared chemiresistive sensors based on wide-area graphene (grown by chemical vapor deposition) placed on Si/Si3N4 substrates with interdigitated electrodes [...] Read more.
Miniature and low-power gas sensing elements are urgently needed for a portable electronic nose, especially for outdoor pollution monitoring. Hereby we prepared chemiresistive sensors based on wide-area graphene (grown by chemical vapor deposition) placed on Si/Si3N4 substrates with interdigitated electrodes and built-in microheaters. Graphene of each sensor was individually functionalized with ultrathin oxide coating (CuO-MnO2, In2O3 or Sc2O3) by pulsed laser deposition. Over the course of 72 h, the heated sensors were exposed to randomly generated concentration cycles of 30 ppb NO2, 30 ppb O3, 60 ppb NO2, 60 ppb O3 and 30 ppb NO2 + 30 ppb O3 in synthetic air (21% O2, 50% relative humidity). While O3 completely dominated the response of sensors with CuO-MnO2 coating, the other sensors had comparable sensitivity to NO2 as well. Various response features (amplitude, response rate, and recovery rate) were considered as machine learning inputs. Using just the response amplitudes of two complementary sensors allowed us to distinguish these five gas environments with an accuracy of ~ 85%. Misclassification was mostly due to an overlap in the case of the 30 ppb O3, and 30 ppb O3 + 30 ppb NO2 responses, and was largely caused by the temporal drift of these responses. The addition of recovery rates to machine learning input variables enabled us to very clearly distinguish different gases and increase the overall accuracy to ~94%. Full article
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18 pages, 3033 KiB  
Article
High-Sensitivity Metal Oxide Sensors Duplex for On-the-Field Detection of Acetic Acid Arising from the Degradation of Cellulose Acetate-Based Cinematographic and Photographic Films
by Daniele Zappi, Gabriele Varani, Igor Iatsunskyi, Nadja Wallaszkovits, Josef Bailer and Maria Teresa Giardi
Chemosensors 2022, 10(2), 60; https://doi.org/10.3390/chemosensors10020060 - 1 Feb 2022
Cited by 4 | Viewed by 2444
Abstract
In this work, a system consisting of two resistive sensors working in tandem to detect and quantify the acetic acid released during the degradation of cellulose acetate-based ancient cinematographic and photographic films is presented. Acetic acid must be constantly monitored to prevent reaching [...] Read more.
In this work, a system consisting of two resistive sensors working in tandem to detect and quantify the acetic acid released during the degradation of cellulose acetate-based ancient cinematographic and photographic films is presented. Acetic acid must be constantly monitored to prevent reaching concentrations at which autocatalytic degradation processes begin. The sensors are constituted by a thin layer of metal oxide (tungsten oxide and tin oxide) deposited over an interdigitated electrode capable of being heated, chosen to maximize the array response towards acetic acid vapors. The signals obtained from the sensor array are mathematically processed to reduce the background signal due to interferent gases produced during degradation of ancient cinematographic films. The sensor array reported a LOD of 30 ppb for acetic acid, with a linearity range up to 30 ppm. Finally, the sensor array was tested with different cinematographic and photographic film samples made of cellulose acetate, whose degradation state and acetic acid production was validated using the conventional technique (A-D strips). The presented array is suitable for remote monitoring large number of films in collections since, compared to the official technique, it has a lower detection limit (30 ppb vs. 500 ppb) and is much quicker in providing accurate acetic acid concentration in the film boxes (15 min vs. 24 h). Full article
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15 pages, 5001 KiB  
Article
Adsorption Kinetics of NO2 Gas on Pt/Cr-TiO2/Pt-Based Sensors
by Azhar Ali Haidry, Qawareer Fatima, Ahmar Mehmood, Asim Shahzad, Yinwen Ji and Bilge Saruhan
Chemosensors 2022, 10(1), 11; https://doi.org/10.3390/chemosensors10010011 - 27 Dec 2021
Cited by 8 | Viewed by 2932
Abstract
Metal oxides are excellent candidates for the detection of various gases; however, the issues such as the limited operating temperature and selectivity are the most important ones requiring the comprehensive understanding of gas adsorption kinetics on the sensing layer surfaces. To this context, [...] Read more.
Metal oxides are excellent candidates for the detection of various gases; however, the issues such as the limited operating temperature and selectivity are the most important ones requiring the comprehensive understanding of gas adsorption kinetics on the sensing layer surfaces. To this context, the present study focuses mainly on the fabrication of a Pt/Cr-TiO2/Pt type sensor structure that is highly suitable in reducing the operating temperature (from 400 to 200 °C), extending the lower limit NO2 gas concentration (below 10 ppm) with fast response (37 s) and recovery (24 s) times. This illustrates that the sensor performance is not only solely dependent on the nature of sensing material, but also, it is significantly enhanced by using such a new kind of electrode geometry. Moreover, Cr doping into TiO2 culminates in altering the sensor response from n- to p-type and thus contributes to sensor performance enhancement by detecting low NO2 concentrations selectively at reduced operating temperatures. In addition, the NO2 surface adsorption kinetics are studied by fitting the obtained sensor response curves with Elovich, inter-particle diffusion, and pseudo first-order and pseudo second-order adsorption models. It is found that a pseudo first-order reaction model describes the best NO2 adsorption kinetics toward 7–170 ppm NO2 gas at 200 °C. Finally, the sensing mechanism is discussed on the basis of the obtained results. Full article
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16 pages, 5309 KiB  
Article
Macrocycle-Functionalized RGO for Gas Sensors for BTX Detection Using a Double Transduction Mode
by Elisa Ruiz, Thiaka Gueye, Claire Masson, Christelle Varenne, Alain Pauly, Jérôme Brunet and Amadou L. Ndiaye
Chemosensors 2021, 9(12), 346; https://doi.org/10.3390/chemosensors9120346 - 7 Dec 2021
Cited by 6 | Viewed by 2726
Abstract
To fabricate mass and resistive sensors based on reduced graphene oxide (RGO), we investigated the functionalization of RGO by tetra tert-butyl phthalocyanine (PcH2tBu), which possesses a macroring and tert-butyl peripheral groups. Herein, we present the gas sensor responses of the functionalized [...] Read more.
To fabricate mass and resistive sensors based on reduced graphene oxide (RGO), we investigated the functionalization of RGO by tetra tert-butyl phthalocyanine (PcH2tBu), which possesses a macroring and tert-butyl peripheral groups. Herein, we present the gas sensor responses of the functionalized RGO toward benzene, toluene, and xylene (BTX) vapors. The RGO was obtained by the reduction of graphene oxide (GO) using citrate as a reducing agent, while the functionalization was achieved non-covalently by simply using ultrasonic and heating treatment. The sensor devices based on both QCM (quartz crystal microbalance) and resistive transducers were used simultaneously to understand the reactivity. Both the GO and the RGO showed less sensitivity to BTX vapors, while the RGO/PcH2tBu presented enhanced sensor responses. These results show that the p-network plays a very important role in targeting BTX vapors. The resistive response analysis allowed us to state that the RGO is a p-type semiconductor and that the interaction is governed by charge transfer, while the QCM response profiles allowed use to determine the differences between the BTX vapors. Among BTX, benzene shows the weakest sensitivity and a reactivity in the higher concentration range (>600 ppm). The toluene and xylene showed linear responses in the range of 100–600 ppm. Full article
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17 pages, 10640 KiB  
Article
Effect of Al and Mg Doping on Reducing Gases Detection of ZnO Nanoparticles
by Soumaya Jaballah, Yazeed Alaskar, Ibrahim AlShunaifi, Imed Ghiloufi, Giovanni Neri, Chaker Bouzidi, Hassen Dahman and Lassaad El Mir
Chemosensors 2021, 9(11), 300; https://doi.org/10.3390/chemosensors9110300 - 24 Oct 2021
Cited by 17 | Viewed by 2880
Abstract
In this work, the main objective is to enhance the gas sensing capability through investigating the effect of Al and Mg doping on ZnO based sensors. ZnO, Mg1% doped ZnO, Al5% doped ZnO and (Al5%, Mg1%) co-doped ZnO [...] Read more.
In this work, the main objective is to enhance the gas sensing capability through investigating the effect of Al and Mg doping on ZnO based sensors. ZnO, Mg1% doped ZnO, Al5% doped ZnO and (Al5%, Mg1%) co-doped ZnO nanoparticles (NPs) were synthesized by a modified sol-gel method. The structural characterization showed the hexagonal crystalline structure of the prepared samples. Morphological characterizations confirmed the nanometric sizes of the NPs (27–57 nm) and elemental composition investigation proved the existence of Al and Mg with low concentrations. The optical characterization showed the high absorbance of the synthesized samples in the UV range. The gas sensing performances of the synthesized samples, prepared in the form of thick films, were investigated. Sensing tests demonstrated the high influence of the Al and Mg on the sensing performances towards H2 and CO gas, respectively. The 5A1MZO-based sensor exhibits high sensitivity and low detection limits to H2 (<2 ppm) and CO (<1 ppm). It showed a response around 70 (at 250 °C) towards 2000 ppm H2 and 2 (at 250 °C) towards CO. Full article
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Review

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40 pages, 4801 KiB  
Review
Magneto-Electronic Hydrogen Gas Sensors: A Critical Review
by Ivan S. Maksymov and Mikhail Kostylev
Chemosensors 2022, 10(2), 49; https://doi.org/10.3390/chemosensors10020049 - 28 Jan 2022
Cited by 13 | Viewed by 5026
Abstract
Devices enabling early detection of low concentrations of leaking hydrogen and precision measurements in a wide range of hydrogen concentrations in hydrogen storage systems are essential for the mass-production of fuel-cell vehicles and, more broadly, for the transition to the hydrogen economy. Whereas [...] Read more.
Devices enabling early detection of low concentrations of leaking hydrogen and precision measurements in a wide range of hydrogen concentrations in hydrogen storage systems are essential for the mass-production of fuel-cell vehicles and, more broadly, for the transition to the hydrogen economy. Whereas several competing sensor technologies are potentially suitable for this role, ultra-low fire-hazard, contactless and technically simple magneto-electronic sensors stand apart because they have been able to detect the presence of hydrogen gas in a range of hydrogen concentrations from 0.06% to 100% at atmospheric pressure with the response time approaching the industry gold standard of one second. This new kind of hydrogen sensors is the subject of this review article, where we inform academic physics, chemistry, material science and engineering communities as well as industry researchers about the recent developments in the field of magneto-electronic hydrogen sensors, including those based on magneto-optical Kerr effect, anomalous Hall effect and Ferromagnetic Resonance with a special focus on Ferromagnetic Resonance (FMR)-based devices. In particular, we present the physical foundations of magneto-electronic hydrogen sensors and we critically overview their advantages and disadvantages for applications in the vital areas of the safety of hydrogen-powered cars and hydrogen fuelling stations as well as hydrogen concentration meters, including those operating directly inside hydrogen-fuelled fuel cells. We believe that this review will be of interest to a broad readership, also facilitating the translation of research results into policy and practice. Full article
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20 pages, 4770 KiB  
Review
CuxO Nanostructure-Based Gas Sensors for H2S Detection: An Overview
by Sachin Navale, Mehrdad Shahbaz, Sanjit Manohar Majhi, Ali Mirzaei, Hyoun Woo Kim and Sang Sub Kim
Chemosensors 2021, 9(6), 127; https://doi.org/10.3390/chemosensors9060127 - 2 Jun 2021
Cited by 34 | Viewed by 4938
Abstract
H2S gas is a toxic and hazardous byproduct of the oil and gas industries. It paralyzes the olfactory nerves, with concentrations above 100 ppm, resulting in loss of smell; prolonged inhalation may even cause death. One of the most important semiconducting [...] Read more.
H2S gas is a toxic and hazardous byproduct of the oil and gas industries. It paralyzes the olfactory nerves, with concentrations above 100 ppm, resulting in loss of smell; prolonged inhalation may even cause death. One of the most important semiconducting metal oxides for the detection of H2S is CuxO (x = 1, 2), which is converted to CuxS upon exposure to H2S, leading to a remarkable modulation in the resistance and appearance of an electrical sensing signal. In this review, various morphologies of CuxO in the pristine form, composites of CuxO with other materials, and decoration/doping of noble metals on CuxO nanostructures for the reliable detection of H2S gas are thoroughly discussed. With an emphasis to the detection mechanism of CuxO-based gas sensors, this review presents findings that are of considerable value as a reference. Full article
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