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19 pages, 12552 KiB

Open AccessArticle

The Use of Low-Cost Gas Sensors for Air Quality Monitoring with Smartphone Technology: A Preliminary Study

by Domenico Suriano, Francis Olawale Abulude and Michele Penza

Chemosensors 2025, 13(5), 189; https://doi.org/10.3390/chemosensors13050189 - 20 May 2025

In the past decades, both low-cost gas sensors for air quality monitoring and smartphone devices have experienced a remarkable spread in the worldwide market. Smartphone devices have become a unique tool in everyday life, whilst the use of low-cost gas sensors in air [...] Read more.

In the past decades, both low-cost gas sensors for air quality monitoring and smartphone devices have experienced a remarkable spread in the worldwide market. Smartphone devices have become a unique tool in everyday life, whilst the use of low-cost gas sensors in air quality monitors has allowed for a better understanding of the personal exposure to air pollutants. The traditional technologies for measuring air pollutant concentrations, even though they provide accurate data, cannot assure the necessary spatio-temporal resolution for assessing personal exposure to the various air pollutants. In this respect, one of the most promising solutions appears to be the use of smartphones together with the low-cost miniaturized gas sensors, because it allows for the monitoring of the air quality characterizing the different environments frequented in everyday life by leveraging the capability to perform mobile measurements. In this research, a handheld air quality monitor based on low-cost gas sensors capable of connecting to smartphone devices via Bluetooth link has been designed and implemented to explore the different ways of its use for assessing the personal exposure to air pollutants. For this purpose, two experiments were carried out: the first one was indoor monitoring of CO and NO₂ concentrations performed in an apartment occupied by four individuals and the second one was mobile monitoring of CO and NO₂ performed in a car cabin. During the indoor measurements, the maximum value for the CO concentrations was equal to 12.3 ppm, whilst the maximum value for NO₂ concentrations was equal to 64 ppb. As concerns the mobile measurements, the maximum concentration of CO was equal to 8.3 ppm, whilst the maximum concentration of NO₂ was equal to 38 ppb. This preliminary study has shown that this system can be potentially used in all those situations where the use of traditional chemical analyzers for measuring gas concentrations in everyday life environments is hardly feasible, but also has highlighted some limits concerning the performance of such systems. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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16 pages, 5088 KiB

Open AccessArticle

A Minimal Electronic Nose Based on Graphene Functionalized with Metalated Pyrazinoporphyrazines and Phthalocyanines for Ammonia, Benzene, and Hydrogen Sulfide Discrimination

by Sonia Freddi, Luca Vaghi, Andrea Penoni, Luca Scapinello and Luigi Sangaletti

Chemosensors 2025, 13(5), 165; https://doi.org/10.3390/chemosensors13050165 - 5 May 2025

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Abstract

The development of electronic noses is, nowadays, essential for several applications, including breath analysis and industrial security. Ammonia, benzene, and hydrogen sulfide are particularly important due to their environmental and health impacts. Here, graphene-based sensors, functionalized with unconventional in-house synthesized zinc and copper [...] Read more.

The development of electronic noses is, nowadays, essential for several applications, including breath analysis and industrial security. Ammonia, benzene, and hydrogen sulfide are particularly important due to their environmental and health impacts. Here, graphene-based sensors, functionalized with unconventional in-house synthesized zinc and copper octyl-pyrazinoporphyrazines and commercially available zinc phthalocyanine, have been prepared. Enhanced solubility given by the octyl chains allowed us to exploit drop-casting as a straightforward functionalization technique. The sensors demonstrated excellent performance for detecting ammonia, benzene, and hydrogen sulfide as a single sensor, with a competitive detection limit and a high sensitivity compared to the state of the art. In particular, functionalization enabled the detection of hydrogen sulfide, for which no response is observed with bare graphene, and lowered the detection limit for all the gases compared to bare graphene. Additionally, the prepared sensors have been assembled into an e-nose that shows promising potentiality to be used for both industrial and medical applications thanks to its excellent discrimination capability of single gases and mixtures. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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13 pages, 3014 KiB

Open AccessArticle

Construction of 2D TiO₂@MoS₂ Heterojunction Nanosheets for Efficient Toluene Gas Detection

by Dehui Wang, Jinwu Hu, Hui Xu, Ding Wang and Guisheng Li

Chemosensors 2025, 13(5), 154; https://doi.org/10.3390/chemosensors13050154 - 22 Apr 2025

Viewed by 289

Abstract

Monitoring trace toluene exposure is critical for early-stage lung cancer screening via breath analysis, yet conventional chemiresistive sensors face fundamental limitations, including compromised selectivity in complex VOC matrices and humidity-induced signal drift, with prevailing p–n heterojunction architectures suffering from inherent charge recombination and [...] Read more.

Monitoring trace toluene exposure is critical for early-stage lung cancer screening via breath analysis, yet conventional chemiresistive sensors face fundamental limitations, including compromised selectivity in complex VOC matrices and humidity-induced signal drift, with prevailing p–n heterojunction architectures suffering from inherent charge recombination and environmental instability. Herein, we pioneer a 2D core–shell n–n heterojunction strategy through rational design of TiO₂@MoS₂ heterostructures, where vertically aligned MoS₂ nanosheets are epitaxially grown on 2D TiO₂ derived from graphene-templated synthesis, creating built-in electric fields at the heterojunction interface that dramatically enhance charge carrier separation efficiency. At 240 °C, the TiO₂@MoS₂ sensor exhibits a superior response (R_a/R_g = 9.8 to 10 ppm toluene), outperforming MoS₂ (R_a/R_g = 2.8). Additionally, the sensor demonstrates rapid response/recovery kinetics (9 s/16 s), a low detection limit (50 ppb), and excellent selectivity against interfering gases and moisture. The enhanced performance is attributed to unidirectional electron transfer (TiO₂ → MoS₂) without hole recombination losses, methyl-specific adsorption through TiO₂ oxygen vacancy alignment, and steric exclusion of non-target VOCs via size-selective MoS₂ interlayers. This work establishes a transformative paradigm in gas sensor design by leveraging n–n heterojunction physics and 2D core–shell synergy, overcoming long-standing limitations of conventional architectures. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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18 pages, 4156 KiB

Open AccessArticle

Influence of P(V3D3-co-TFE) Copolymer Coverage on Hydrogen Detection Performance of a TiO₂ Sensor at Different Relative Humidity for Industrial and Biomedical Applications

by Mihai Brinza, Lynn Schwäke, Lukas Zimoch, Thomas Strunskus, Thierry Pauporté, Bruno Viana, Tayebeh Ameri, Rainer Adelung, Franz Faupel, Stefan Schröder and Oleg Lupan

Chemosensors 2025, 13(4), 150; https://doi.org/10.3390/chemosensors13040150 - 19 Apr 2025

Viewed by 354

Abstract

The detection of hydrogen gas is crucial for both industrial fields, as a green energy carrier, and biomedical applications, where it is a biomarker for diagnosis. TiO₂ nanomaterials are stable and sensitive to hydrogen gas, but their gas response can be negatively [...] Read more.

The detection of hydrogen gas is crucial for both industrial fields, as a green energy carrier, and biomedical applications, where it is a biomarker for diagnosis. TiO₂ nanomaterials are stable and sensitive to hydrogen gas, but their gas response can be negatively affected by external factors such as humidity. Therefore, a strategy is required to mitigate these influences. The utilization of organic–inorganic hybrid gas sensors, specifically metal oxide gas sensors coated with ultra-thin copolymer films, is a relatively novel approach in this field. In this study, we examined the performance and long-term stability of novel TiO₂-based sensors that were coated with poly(trivinyltrimethylcyclotrisiloxane-co-tetrafluoroethylene) (P(V3D3-co-TFE)) co-polymers. The P(V3D3-co-TFE)/TiO₂ hybrid sensors exhibit high reliability even for more than 427 days. They exhibit excellent hydrogen selectivity, particularly in environments with high humidity. An optimum operating temperature of 300 °C to 350 °C was determined. The highest recorded response to H₂ was approximately 153% during the initial set of measurements at a relative humidity of 10%. The developed organic–inorganic hybrid structures open wide opportunities for gas sensor tuning and customization, paving the way for innovative applications in industry and biomedical fields, such as exhaled breath analysis, etc. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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14 pages, 10364 KiB

Open AccessArticle

SnO₂-Based CMOS-Integrated Gas Sensor Optimized by Mono-, Bi-, and Trimetallic Nanoparticles

by Larissa Egger, Florentyna Sosada-Ludwikowska, Stephan Steinhauer, Vidyadhar Singh, Panagiotis Grammatikopoulos and Anton Köck

Chemosensors 2025, 13(2), 59; https://doi.org/10.3390/chemosensors13020059 - 8 Feb 2025

Cited by 1 | Viewed by 868

Abstract

Chemical sensors, relying on electrical conductance changes in a gas-sensitive material due to the surrounding gas, have the (dis-)advantage of reacting with multiple target gases and humidity. In this work, we report CMOS-integrated SnO₂ thin film-based gas sensors, which are functionalized with [...] Read more.

Chemical sensors, relying on electrical conductance changes in a gas-sensitive material due to the surrounding gas, have the (dis-)advantage of reacting with multiple target gases and humidity. In this work, we report CMOS-integrated SnO₂ thin film-based gas sensors, which are functionalized with mono-, bi-, and trimetallic nanoparticles (NPs) to optimize the sensor performance. The spray pyrolysis technology was used to deposit the metal oxide sensing layer on top of a CMOS-fabricated micro-hotplate (µhp), and magnetron sputtering inert-gas condensation was employed to functionalize the sensing layer with metallic NPs, Ag-, Pd-, and Ru-NPs, and all combinations thereof were used as catalysts to improve the sensor response to carbon monoxide and to suppress the cross-sensitivity toward humidity. The focus of this work is the detection of toxic carbon monoxide and a specific hydrocarbon mixture (HC_mix) in a concentration range of 5–50 ppm at different temperatures and humidity levels. The use of CMOS chips ensures low-power, integrated sensors, ready to apply in cell phones, watches, etc., for air quality-monitoring purposes. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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14 pages, 4197 KiB

Open AccessArticle

Effects of Base Materials (α-Alumina and/or γ-Alumina) on Volatile Organic Compounds (VOCs)-Sensing Properties of Adsorption/Combustion-Type Microsensors

by Takeo Hyodo, Yuma Matsuura, Genki Inao, Takahiko Sasahara, Yasuhiro Shimizu and Taro Ueda

Chemosensors 2025, 13(1), 9; https://doi.org/10.3390/chemosensors13010009 - 7 Jan 2025

Viewed by 2846

Abstract

The sensing properties of adsorption/combustion-type microsensors using 5 wt% Pt-loaded aluminas, which consist of two kinds of alumina (α-Al₂O₃ and γ-Al₂O₃), as sensing (catalytic) materials for ethanol and toluene, were investigated in air, and the mixing [...] Read more.

The sensing properties of adsorption/combustion-type microsensors using 5 wt% Pt-loaded aluminas, which consist of two kinds of alumina (α-Al₂O₃ and γ-Al₂O₃), as sensing (catalytic) materials for ethanol and toluene, were investigated in air, and the mixing effects of α-Al₂O₃ with γ-Al₂O₃ on the dynamic and static responses of the sensors were discussed in this study. The mixing of 50 wt% α-Al₂O₃ with γ-Al₂O₃ was the most effective in enhancing the dynamic responses to ethanol, which originated from the flash combustion behavior of ethanol and/or their partially decomposed products adsorbed on the sensing films from 150 °C to 450 °C, while further mixing of α-Al₂O₃ with γ-Al₂O₃ tended to increase the dynamic responses to toluene. On the other hand, the static responses to both ethanol and toluene, which arise from their catalytic combustion at elevated temperatures (450 °C), mainly increased with an increase in the addition of α-Al₂O₃ in the 5 wt% Pt-loaded aluminas. These results indicate that the synergistic effects of the catalytic activity and the thermal conductivity of the 5 wt% Pt-loaded aluminas are the most important for the sensing properties of these sensors to ethanol and toluene. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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12 pages, 5960 KiB

Open AccessArticle

CRDS Technology-Based Integrated Breath Gas Detection System for Breath Acetone Real-Time Accurate Detection Application

by Jing Sun, Dongxin Shi, Le Wang, Xiaolin Yu, Binghong Song, Wangxin Li, Jiankun Zhu, Yong Yang, Bingqiang Cao and Chenyu Jiang

Chemosensors 2024, 12(12), 261; https://doi.org/10.3390/chemosensors12120261 - 13 Dec 2024

Viewed by 1024

Abstract

The monitoring of acetone in exhaled breath is expected to provide a noninvasive and painless method for dynamic monitoring of summarized physiological metabolic status during obesity treatment. Although the commonly used Mass Spectrometry (MS) technology has high accuracy, the long detection time and [...] Read more.

The monitoring of acetone in exhaled breath is expected to provide a noninvasive and painless method for dynamic monitoring of summarized physiological metabolic status during obesity treatment. Although the commonly used Mass Spectrometry (MS) technology has high accuracy, the long detection time and large equipment size limit the application of daily bedside detection. As for the real-time and accurate detection of acetone, the gas sensor has become the best choice of gas detection technology, but it is easy to be disturbed by water vapor in breath gas. An integrated breath gas detection system based on cavity ring-down spectroscopy (CRDS) is reported in this paper, which is a laser absorption spectroscopy technique with high-sensitivity detection and absolute quantitative analysis. The system uses a 266 nm single-wavelength ultraviolet laser combined with a breath gas pretreatment unit to effectively remove the influence of water vapor. The ring-down time of this system was 1.068 μs, the detection sensitivity was 1 ppb, and the stability of the system was 0.13%. The detection principle of the integrated breath gas detection system follows Lambert–Beer’s law, which is an absolute measurement with very high detection accuracy, and was further validated by Gas Chromatography–Mass Spectrometer (GC-MS) testing. Significant differences in the response of the integrated breath gas detection system to simulated gases containing different concentrations of acetone indicate the potential of the system for the detection of trace amounts of acetone. Meanwhile, the monitoring of acetone during obesity treatment also signifies the feasibility of this system in the dynamic monitoring of physiological indicators, which is not only important for the optimization of the obesity treatment process but also promises to shed further light on the interaction between obesity treatment and physiological metabolism in medicine. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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19 pages, 8894 KiB

Open AccessArticle

The Effect of Doping rGO with Nanosized MnO₂ on Its Gas Sensing Properties

by Mohamed Ayoub Alouani, Juan Casanova-Chafer, Santiago de Bernardi-Martín, Alejandra García-Gómez, Foad Salehnia, José Carlos Santos-Ceballos, Alejandro Santos-Betancourt, Xavier Vilanova and Eduard Llobet

Chemosensors 2024, 12(12), 256; https://doi.org/10.3390/chemosensors12120256 - 6 Dec 2024

Cited by 2 | Viewed by 1220

Abstract

Manganese dioxide (MnO₂) has drawn attention as a sensitiser to be incorporated in graphene-based chemoresistive sensors thanks to its promising properties. In this regard, a rGO@MnO₂ sensing material was prepared and deposited on two different substrates (silicon and Kapton). The [...] Read more.

Manganese dioxide (MnO₂) has drawn attention as a sensitiser to be incorporated in graphene-based chemoresistive sensors thanks to its promising properties. In this regard, a rGO@MnO₂ sensing material was prepared and deposited on two different substrates (silicon and Kapton). The effect of the substrate nature on the morphology and sensing behaviour of the rGO@MnO₂ material was thoroughly analysed and reported. These sensors were exposed to different dilutions of NO₂ ranging from 200 ppb to 1000 ppb under dry and humid conditions (25% RH and 70% RH) at room temperature. rGO@MnO₂ deposited on Kapton showed the highest response of 6.6% towards 1 ppm of NO₂ under dry conditions at RT. Other gases or vapours such as NH₃, CO, ethanol, H₂ and benzene were also tested. FESEM, HRTEM, Raman, XRD and ATR-IR were used to characterise the prepared sensors. The experimental results showed that the incorporation of nanosized MnO₂ in the rGO material enhanced its response towards NO₂. Moreover, this material also showed very good responses toward NH₃ both under dry and humid conditions, with the rGO@MnO₂ sensor on silicon showing the highest response of 18.5% towards 50 ppm of NH₃ under 50% RH at RT. Finally, the synthetised layers showed no cross-responsiveness towards other toxic gases. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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14 pages, 3995 KiB

Open AccessArticle

An Intensity-Variation RI Sensor for Multi-Variant Alcohol Detection with Twisted Structure Using Polymer Optical Fiber

by Abdul Ghaffar, Rehan Mehdi, Irfan Mehdi, Bhagwan Das, Vicky Kumar, Sadam Hussain, Gul Sher, Kamran Ali Memon, Sikandar Ali, Mujahid Mehdi and Khurram Karim Qureshi

Chemosensors 2024, 12(12), 252; https://doi.org/10.3390/chemosensors12120252 - 3 Dec 2024

Viewed by 1064

Abstract

This research introduces an RI sensor for detecting various alcohol species with a designed twisted polymer optical fiber (POF) sensor. The sensor is developed via a straightforward twisting technique to form an effective coupling mechanism. The sensor works on intensity variation where coupled [...] Read more.

This research introduces an RI sensor for detecting various alcohol species with a designed twisted polymer optical fiber (POF) sensor. The sensor is developed via a straightforward twisting technique to form an effective coupling mechanism. The sensor works on intensity variation where coupled intensity varies when different types of alcohol are added. The structure relies on the twisting of two fibers, where one fiber is used as the illuminating fiber and the other fiber is used as the receiving fiber. Five different types of alcohol are tested (methanol, ethanol, propanol, butanol, and pentanol) as a substant. The experimental results reveal that the sensor is able to detect all five distinct substants effectively by optical power intensity variation. Moreover, the sensor’s sensitivity is analyzed with different factors such as the influence of the bending radius and the coupling length, which reveals that the sensing parameters could be customized depending on specific requirements. The sensor demonstrated consistent responses in repeatability tests, with minimal variation across multiple measurements, highlighting its stability. Additionally, the study explores temperature’s influence, revealing a sensitivity shift for every degree Celsius of change. This POF-based alcohol sensor represents a significant leap forward in optical sensing technology. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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12 pages, 8606 KiB

Open AccessArticle

CO₂ Interaction Mechanism of SnO₂-Based Sensors with Respect to the Pt Interdigital Electrodes Gap

by Adelina Stanoiu, Alexandra Corina Iacoban, Catalina Gabriela Mihalcea, Ion Viorel Dinu, Ovidiu Gabriel Florea, Ioana Dorina Vlaicu and Cristian Eugen Simion

Chemosensors 2024, 12(11), 238; https://doi.org/10.3390/chemosensors12110238 - 16 Nov 2024

Viewed by 1215

Abstract

The tuning sensitivity towards CO₂ detection under in-field-like conditions was investigated using SnO₂-sensitive material deposited onto Al₂O₃ substrates provided with platinum electrodes with interdigital gaps of 100 µm and 30 µm. X-ray diffraction, low-magnification and high-resolution transmission [...] Read more.

The tuning sensitivity towards CO₂ detection under in-field-like conditions was investigated using SnO₂-sensitive material deposited onto Al₂O₃ substrates provided with platinum electrodes with interdigital gaps of 100 µm and 30 µm. X-ray diffraction, low-magnification and high-resolution transmission electron microscopy, and electrical and contact potential difference investigations were employed to understand the sensing mechanism involved in CO₂ detection. The morpho-structural analysis revealed that the SnO₂ nanoparticles exhibit well-defined facets along the (110) and (101) crystallographic planes. Complex phenomenological investigations showed that moisture significantly affects the gas sensing performance. The experimental results corroborated the literature evidence, highlighting the importance of Pt within the interdigital electrodes subsequently reflected in the increase in the CO₂ sensing performance with the decrease in the interdigital gap. The catalytic efficiency is explained by the distribution of platinum at the gas-Pt-SnO₂ three-phase boundary, which is critical for enhancing the sensor performance. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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12 pages, 4415 KiB

Open AccessArticle

A Novel Mechanism Based on Oxygen Vacancies to Describe Isobutylene and Ammonia Sensing of p-Type Cr₂O₃ and Ti-Doped Cr₂O₃ Thin Films

by Pengfei Zhou, Jone-Him Tsang, Chris Blackman, Yanbai Shen, Jinsheng Liang, James A. Covington, John Saffell and Ehsan Danesh

Chemosensors 2024, 12(10), 218; https://doi.org/10.3390/chemosensors12100218 - 18 Oct 2024

Cited by 1 | Viewed by 1285

Abstract

Gas sensors based on metal oxide semiconductors (MOS) have been widely used for the detection and monitoring of flammable and toxic gases. In this paper, p-type Cr₂O₃ and Ti-doped Cr₂O₃ (CTO) thin films were synthesized using an [...] Read more.

Gas sensors based on metal oxide semiconductors (MOS) have been widely used for the detection and monitoring of flammable and toxic gases. In this paper, p-type Cr₂O₃ and Ti-doped Cr₂O₃ (CTO) thin films were synthesized using an aerosol-assisted chemical vapor deposition (AACVD) method. Detailed analysis of the thin films deposited, including structural information, their elemental composition, oxidation state, and morphology, was investigated using XRD, Raman analysis, SEM, and XPS. All the gas sensors based on pristine Cr₂O₃ and CTO exhibited a reversible response and good sensitivity to isobutylene (C₄H₈) and ammonia (NH₃) gases. Doping Ti into the Cr₂O₃ lattice improves the response of the CTO-based sensors to C₄H₈ and NH₃. We describe a novel mechanism for the gas sensitivity of p-type metal oxides based on variations in the oxygen vacancy concentration. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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13 pages, 8362 KiB

Open AccessArticle

Low-Drift NO₂ Sensor Based on Polyaniline/Black Phosphorus Composites at Room Temperature

by Bolun Tang, Yunbo Shi, Jijiang Liu, Canda Zheng, Kuo Zhao, Jianhua Zhang and Qiaohua Feng

Chemosensors 2024, 12(9), 181; https://doi.org/10.3390/chemosensors12090181 - 5 Sep 2024

Cited by 2 | Viewed by 1248

Abstract

In this paper, a room-temperature NO₂ sensor based on a polyaniline (PANI)/black phosphorus (BP) composite material was proposed to solve the power consumption problem of traditional metal-oxide sensors operating at high temperatures. PANI was synthesized by chemical oxidative polymerization, whereas BP was [...] Read more.

In this paper, a room-temperature NO₂ sensor based on a polyaniline (PANI)/black phosphorus (BP) composite material was proposed to solve the power consumption problem of traditional metal-oxide sensors operating at high temperatures. PANI was synthesized by chemical oxidative polymerization, whereas BP was synthesized by low-pressure mineralization. The PANI/BP composite materials were prepared via ultrasonic exfoliation and mixing. Various characterization techniques, including scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), confirmed the successful preparation of the PANI/BP composites and their excellent structural properties. The sensor demonstrated outstanding gas sensitivity in the NO₂ concentration range of 2–60 ppm. In particular, the sensor showed a response exceeding 2200% at 60 ppm NO₂ concentration when using a 1:1 mass ratio of PANI to BP in the composite material. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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Review

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28 pages, 7372 KiB

Open AccessReview

Progress in Layered Double Hydroxide-Based Materials for Gas and Electrochemical Sensing Applications

by Waseem Raza, Khursheed Ahmad and Tae Hwan Oh

Chemosensors 2025, 13(3), 115; https://doi.org/10.3390/chemosensors13030115 - 20 Mar 2025

Viewed by 438

Abstract

In the current scenario, it is considered that environmental pollution is one of the significant challenges for the global world. Various toxic and hazardous substances such as hydrazine, phenolic compounds, and pharmaceutical waste significantly contribute to environmental pollution. Exposure to such substances and [...] Read more.

In the current scenario, it is considered that environmental pollution is one of the significant challenges for the global world. Various toxic and hazardous substances such as hydrazine, phenolic compounds, and pharmaceutical waste significantly contribute to environmental pollution. Exposure to such substances and compounds increases the chances of negative effects on human health as well as the environment. Therefore, it is considered that monitoring toxic gases and hazardous substances/compounds is of great significance. In the past few years, layered double hydroxide (LDH)-based materials have received significant interest for gas sensing and electrochemical sensing studies. The presence of layered structured, larger surface area, decent conductivity, and electrochemical properties makes them a suitable material for sensing applications. This motivates us to summarize the recent progress in the development of LDH material-based gas and electrochemical sensors for the detection of toxic and hazardous gases/compounds. It was observed in previous reports that LDH-based materials are promising candidates for gas sensing as well as electrochemical sensing applications. It was found that LDH and its composites may exhibit larger surface areas and high electrical conductivity when combined with other materials such as metal oxides, MXenes, polymers, and metal sulfides. Thus, researchers prepared hybrid composites of LDH-based materials for gas and electrochemical sensing applications. It is worth mentioning that many solvents which have negative impacts on the environment could not be detected by electrochemical methods, while some toxic compounds/substances could not be determine by gas sensing methods. This may create a gap between the determinations of different kinds of pollutants that exist in the environment. Thus, it is required to find a bi-functional material which can be used for kind of sensing technology. In addition, it may also overcome the limitations or gap between the two sensing techniques. LDH-based materials have demonstrated excellent performance in gas and electrochemical sensing technologies. Thus, it would be of great significance to employ the single LDH-based materials for gas as well as electrochemical sensing applications. In this review article, we have tried our best to compile the progress in the various LDH-based materials for gas sensing and electrochemical sensing applications towards the detection of hazardous compounds. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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21 pages, 15416 KiB

Open AccessReview

The Screening and Diagnosis Technologies Towards Pneumoconiosis: From Imaging Analysis to E-Noses

by Yuqian Zhang, Wufan Xuan, Shuai Chen, Mingna Yang and Huakun Xing

Chemosensors 2025, 13(3), 102; https://doi.org/10.3390/chemosensors13030102 - 11 Mar 2025

Cited by 2 | Viewed by 803

Abstract

Pneumoconiosis, as the most widely distributed occupational disease globally, poses serious health and social hazards. Its diagnostic techniques have evolved from conventional imaging and computer-assisted analysis to emerging sensor strategies covering biomarker analysis, routine breath sensing, integrated electronic nose (E-nose), etc. All of [...] Read more.

Pneumoconiosis, as the most widely distributed occupational disease globally, poses serious health and social hazards. Its diagnostic techniques have evolved from conventional imaging and computer-assisted analysis to emerging sensor strategies covering biomarker analysis, routine breath sensing, integrated electronic nose (E-nose), etc. All of them both have special advantages and face shortcomings or challenges in practical application. In recent years, the emergence of advanced data analysis technologies, including artificial intelligence (AI), has provided opportunities for large-scale screening of pneumoconiosis. On the basis of a deep analysis of the characteristics of the technologies for screening and diagnosis of pneumoconiosis, this paper comprehensively and systematically reviews the current development of these technologies, especially focusing on the research progress of emerging sensor technologies, and provides a forecast for their future development. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

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