Nanomaterial Based Gas Sensors for Environmental Air Pollutant Detection

Topic Information

Dear Colleagues,

Rapid industrialization around the world and the poor monitoring of pollutants in the air is obviously putting ecosystems and human life at greater risk than ever before. Air pollutants, mostly produced from industrial activities, automobiles, and other combustion sources, are being directly emitted into the atmosphere, thereby altering the quality and safety of environmental air and causing a significant threat to the wellbeing and lifestyles of humans. Despite many countries and local authorities introducing certain regulations and mechanisms to combat and control air pollutants, the lack of concerted global efforts and smart technologies to continuously measure, analyze and monitor pollutants is still a pressing issue. Given to their excellent selectivity, sensitivity, and miniaturization, gas sensors based on functional nanomaterials present an alternative nanotechnolgy to detect air pollutants and to monitor the safety and quality of environmental air. Thus, gas sensors based on nanostructured materials, polymers, nanocomposites, and thin films demonstrate excellent features for the detection and determination of both primary and secondary air pollutants. Hence, in light of this pressing issue, this Topic aims at convering the latest nanomaterial-based gas sensors and mechanisms for the detection and determination of air pollutants and the way forward to bring such technologies to a greater usage. We look forward to and welcome your participation in this topic.

Dr. Tesfalem Welearegay
Dr. Radu Ionescu
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Nano applnano	-	-	2020	23.5 Days	CHF 1000
Biosensors biosensors	5.4	4.9	2011	17.4 Days	CHF 2700
Chemosensors chemosensors	4.2	3.9	2013	17.9 Days	CHF 2700
Materials materials	3.4	5.2	2008	13.9 Days	CHF 2600
Sensors sensors	3.9	6.8	2001	17 Days	CHF 2600

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Published Papers (5 papers)

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All Applied Nano Biosensors Chemosensors Materials Sensors

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15 pages, 5119 KiB  

Open AccessArticle

Influence of Different Pt Functionalization Modes on the Properties of CuO Gas-Sensing Materials

by Xiangxiang Chen, Tianhao Liu, Yunfei Ouyang, Shiyi Huang, Zhaoyang Zhang, Fangzheng Liu, Lu Qiu, Chicheng Wang, Xincheng Lin, Junyan Chen and Yanbai Shen

Sensors 2024, 24(1), 120; https://doi.org/10.3390/s24010120 - 25 Dec 2023

Viewed by 756

Abstract

The functionalization of noble metals is an effective approach to lowering the sensing temperature and improving the sensitivity of metal oxide semiconductor (MOS)-based gas sensors. However, there is a dearth of comparative analyses regarding the differences in sensitization mechanisms between the two functionalization [...] Read more.

The functionalization of noble metals is an effective approach to lowering the sensing temperature and improving the sensitivity of metal oxide semiconductor (MOS)-based gas sensors. However, there is a dearth of comparative analyses regarding the differences in sensitization mechanisms between the two functionalization modes of noble metal loading and doping. In this investigation, we synthesized Pt-doped CuO gas-sensing materials using a one-pot hydrothermal method. And for Pt-loaded CuO, Pt was deposited on the synthesized pristine CuO surface by using a dipping method. We found that both functionalization methods can considerably enhance the response and selectivity of CuO toward NO₂ at low temperatures. However, we observed that CuO with Pt loading had superior sensing performance at 25 °C, while CuO with Pt doping showed more substantial response changes with an increase in the operating temperature. This is mainly due to the different dominant roles of electron sensitization and chemical sensitization resulting from the different forms of Pt present in different functionalization modes. For Pt doping, electron sensitization is stronger, and for Pt loading, chemical sensitization is stronger. The results of this study present innovative ideas for understanding the optimization of noble metal functionalization for the gas-sensing performance of metal oxide semiconductors. Full article

(This article belongs to the Topic Nanomaterial Based Gas Sensors for Environmental Air Pollutant Detection)

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20 pages, 6639 KiB  

Open AccessArticle

Long-Range Network of Air Quality Index Sensors in an Urban Area

by Ionut-Marian Dobra, Vladut-Alexandru Dobra, Adina-Alexandra Dobra, Gabriel Harja, Silviu Folea and Vlad-Dacian Gavra

Sensors 2023, 23(21), 9001; https://doi.org/10.3390/s23219001 - 6 Nov 2023

Viewed by 928

Abstract

In recent times the escalating pollution within densely populated metropolitan areas has emerged as a significant and pressing concern. Authorities are actively grappling with the challenge of devising solutions to promote a cleaner and more environmentally friendly urban landscapes. This paper outlines the [...] Read more.

In recent times the escalating pollution within densely populated metropolitan areas has emerged as a significant and pressing concern. Authorities are actively grappling with the challenge of devising solutions to promote a cleaner and more environmentally friendly urban landscapes. This paper outlines the potential of establishing a LoRa node network within a densely populated urban environment. Each LoRa node in this network is equipped with an air quality measurement sensor. This interconnected system efficiently transmits all the analyzed data to a gateway, which subsequently sends it to a server or database in real time. These data are then harnessed to create a pollution map for the corresponding area, providing users with the opportunity to assess local pollution levels and their recent variations. Furthermore, this information proves valuable when determining the optimal route between two points in the city, enabling users to select the path with the lowest pollution levels, thus enhancing the overall quality of the urban environment. This advantage contributes to alleviating congestion and reducing excessive pollution often concentrated behind buildings or on adjacent streets. Full article

(This article belongs to the Topic Nanomaterial Based Gas Sensors for Environmental Air Pollutant Detection)

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11 pages, 4242 KiB  

Open AccessArticle

Selective NO₂ Detection of CaCu₃Ti₄O₁₂ Ceramic Prepared by the Sol-Gel Technique and DRIFT Measurements to Elucidate the Gas Sensing Mechanism

by Rodrigo Espinoza-González, Josefa Caamaño, Ximena Castillo, Marcelo O. Orlandi, Anderson A. Felix, Marcos Flores, Adriana Blanco, Carmen Castro-Castillo and Francisco Gracia

Materials 2023, 16(9), 3390; https://doi.org/10.3390/ma16093390 - 26 Apr 2023

Cited by 1 | Viewed by 1444

Abstract

NO₂ is one of the main greenhouse gases, which is mainly generated by the combustion of fossil fuels. In addition to its contribution to global warming, this gas is also directly dangerous to humans. The present work reports the structural and gas [...] Read more.

NO₂ is one of the main greenhouse gases, which is mainly generated by the combustion of fossil fuels. In addition to its contribution to global warming, this gas is also directly dangerous to humans. The present work reports the structural and gas sensing properties of the CaCu₃Ti₄O₁₂ compound prepared by the sol-gel technique. Rietveld refinement confirmed the formation of the pseudo-cubic CaCu₃Ti₄O₁₂ compound, with less than 4 wt% of the secondary phases. The microstructural and elemental composition analysis were carried out using scanning electron microscopy and X-ray energy dispersive spectroscopy, respectively, while the elemental oxidation states of the samples were determined by X-ray photoelectron spectroscopy. The gas sensing response of the samples was performed for different concentrations of NO₂, H₂, CO, C₂H₂ and C₂H₄ at temperatures between 100 and 300 °C. The materials exhibited selectivity for NO₂, showing a greater sensor signal at 250 °C, which was correlated with the highest concentration of nitrite and nitrate species on the CCTO surface using DRIFT spectroscopy. Full article

(This article belongs to the Topic Nanomaterial Based Gas Sensors for Environmental Air Pollutant Detection)

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30 pages, 18238 KiB  

Open AccessReview

Accelerating the Gas–Solid Interactions for Conductometric Gas Sensors: Impacting Factors and Improvement Strategies

by Hongchao Zhao, Yanjie Wang and Yong Zhou

Materials 2023, 16(8), 3249; https://doi.org/10.3390/ma16083249 - 20 Apr 2023

Cited by 3 | Viewed by 1966

Abstract

Metal oxide-based conductometric gas sensors (CGS) have showcased a vast application potential in the fields of environmental protection and medical diagnosis due to their unique advantages of high cost-effectiveness, expedient miniaturization, and noninvasive and convenient operation. Of multiple parameters to assess the sensor [...] Read more.

Metal oxide-based conductometric gas sensors (CGS) have showcased a vast application potential in the fields of environmental protection and medical diagnosis due to their unique advantages of high cost-effectiveness, expedient miniaturization, and noninvasive and convenient operation. Of multiple parameters to assess the sensor performance, the reaction speeds, including response and recovery times during the gas–solid interactions, are directly correlated to a timely recognition of the target molecule prior to scheduling the relevant processing solutions and an instant restoration aimed for subsequent repeated exposure tests. In this review, we first take metal oxide semiconductors (MOSs) as the case study and conclude the impact of the semiconducting type as well as the grain size and morphology of MOSs on the reaction speeds of related gas sensors. Second, various improvement strategies, primarily including external stimulus (heat and photons), morphological and structural regulation, element doping, and composite engineering, are successively introduced in detail. Finally, challenges and perspectives are proposed so as to provide the design references for future high-performance CGS featuring swift detection and regeneration. Full article

(This article belongs to the Topic Nanomaterial Based Gas Sensors for Environmental Air Pollutant Detection)

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11 pages, 3959 KiB  

Open AccessArticle

Nanoporous Graphene Oxide-Based Quartz Crystal Microbalance Gas Sensor with Dual-Signal Responses for Trimethylamine Detection

by Guangyu Qi, Fangfang Qu, Lu Zhang, Shihao Chen, Mengyuan Bai, Mengjiao Hu, Xinyan Lv, Jinglei Zhang, Zhenhe Wang and Wei Chen

Sensors 2022, 22(24), 9939; https://doi.org/10.3390/s22249939 - 16 Dec 2022

Cited by 6 | Viewed by 1865

Abstract

This paper presents a straightforward method to develop a nanoporous graphene oxide (NGO)-functionalized quartz crystal microbalance (QCM) gas sensor for the detection of trimethylamine (TMA), aiming to form a reliable monitoring mechanism strategy for low-concentration TMA that can still cause serious odor nuisance. [...] Read more.

This paper presents a straightforward method to develop a nanoporous graphene oxide (NGO)-functionalized quartz crystal microbalance (QCM) gas sensor for the detection of trimethylamine (TMA), aiming to form a reliable monitoring mechanism strategy for low-concentration TMA that can still cause serious odor nuisance. The synthesized NGO material was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy to verify its structure and morphology. Compared with the bare and GO-based QCM sensors, the NGO-based QCM sensor exhibited ultra-high sensitivity (65.23 Hz/μL), excellent linearity (R² = 0.98), high response/recovery capability (3 s/20 s) and excellent repeatability (RSD = 0.02, n = 3) toward TMA with frequency shift and resistance. Furthermore, the selectivity of the proposed NGO-based sensor to TMA was verified by analysis of the dual-signal responses. It is also proved that increasing the conductivity did not improve the resistance signal. This work confirms that the proposed NGO-based sensor with dual signals provides a new avenue for TMA sensing, and the sensor is expected to become a potential candidate for gas detection. Full article

(This article belongs to the Topic Nanomaterial Based Gas Sensors for Environmental Air Pollutant Detection)

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