SO2 Gas Sensor Research Articles

Room-temperature self-calibrating sensor based on CsPbBr3/SnO2 for detecting low-concentration sulfur dioxide

Sulfur dioxide (SO2) is a colorless toxic gas, and accurate monitoring of its concentration is important for safety. However, accuracy is often interfered by humidity. To address the issues, in this work, a self-calibrating SO2 sensor based on CsPbBr3/SnO2 was prepared, the sensor exhibited an excellent response to parts per billion (ppb) levels of SO2 at room temperature, which is rarely achieved by other SO2 sensors. The response sensitivity of the sensor to 600 ppb SO2 reached up to 0.53 with response/recovery times of 17/285 s. In addition, the CsPbBr3/SnO2-based SO2 gas sensor showed a low detection limit, good reproducibility, and high selectivity. Moreover, theoretical calculations show that the gas recognition mechanism is attributed to the significant changes in the band structure and density of states of the heterojunction materials CsPbBr3/SnO2 after gas adsorption, thereby altering the charge carrier transport behavior and electrical properties. A self-calibrating algorithm MobileNetV2 was employed to eliminate humidity interference and effectively identify low-concentration SO2 in humid environments, and the recognition accuracy rate is 0.85. This work demonstrates the production of a high-performance SO2 gas sensor, and provides an effective method to eliminate the interference of humidity, making it significant in environmental monitoring and air quality control.

A CuO/MoO3-based SO2 gas sensor with moisture resistance and ultra-fast response at 90°C

Sulfur dioxide (SO2) is a toxic and harmful decomposition product generated during arc discharge or partial discharge in sulfur hexafluoride (SF6) electrical equipment, which can corrode internal pipelines. Detecting SO2 is crucial for assessing the insulation condition of equipment and preventing faults. To overcome the challenges faced by traditional SO2 gas sensors, including high operating temperatures, slow response times, and poor moisture resistance, this paper proposes a novel SO2 gas sensor based on CuO/MoO3. The morphology, composition, and chemical states of the materials were analyzed using different characterization techniques. At 90°C, the S2 sensor (CuO: MoO3=1: 1) exhibited a fast response time (10 s) to 10 ppm SO2 and demonstrated good moisture resistance (a 1 % change in relative humidity (RH) has the same effect on the sensor as 25.9 ppb SO2). The response of the S2 sensor to 100 ppm SO2 was 26.5. Additionally, the voltage sensitivity of the S2 sensor at low (1–10 ppm) and high (10–100 ppm) concentrations are 658.74 mV/ppm and 33.43 mV/ppm, respectively. Therefore, the S2 sensor is more suitable for low concentration conditions. These good sensing characteristics of the S2 sensor are owing to the high content of oxygen vacancies (39.2 %) and the heterojunction effect in the composite material. Additionally, this sensor exhibits excellent anti-interference capabilities, including moisture resistance and high selectivity. Therefore, the CuO/MoO3-based SO2 gas sensor can be effectively applied to detect the decomposition of SF6.

Effect of NH3 preadsorption on SO2 adsorption on Hf2CO2 MXene

Preadsorbing suitable gas molecule on the substrate can effectively improve the adsorption strength of the system. The adsorption properties of preadsorping NH3 on SO2-adsorbed Hf2CO2 monolayer are explored by first-principles calculation. All possible adsorption sites are considered. SO2 molecule cannot be adsorbed by Hf2CO2 monolayer, while preadsorbing NH3 can increase the adsorption strength of SO2-adsorbed Hf2CO2 monolayer. The adsorption system has the direct semiconductor character and is the reusable SO2 gas sensor because of short recovery time and the appropriate adsorption strength. Preadsorbing NH3 can decrease the carrier mobility in conduction band, but has little impact on the carrier mobility in valence band. The charge transfer of the co-adsorption system is also investigated.

GeC monolayer: A promising 2D material for reusable SO2 and NO2 gas sensor with high sensitivity

Gas sensors are crucial in various fields such as environmental monitoring, industrial production, and healthcare due to their ability to detect harmful gases in real-time. This study investigates GeC monolayer as a potential material for gas sensors targeting sulfur-containing toxic gases (SO2, H2S, SF4) and nitrogen-containing toxic gases (NO, NH3, NO2). The electronic and adsorption properties of GeC monolayer were explored using density functional theory (DFT) calculations. The adsorption of SO2 and nitrogen dioxide significantly affects the band structure and work function of GeC monolayer, indicating that compared to other toxic gases, GeC monolayers exhibit higher sensitivity and selectivity towards SO2 and NO2. The electron localization function analysis indicates that the adsorption process is characterized by physical adsorption. In addition, GeC monolayer exhibits good desorption behavior towards SO2 and NO2 at room temperature. These findings suggest that GeC monolayer is a promising material for developing efficient gas sensors for detecting SO2 and NO2.

GeP3 monolayer as a promising 2D sensing materials in detecting SO2, H2S, SOF2 and SO2F2

The detection of SF6 decomposition components using gas-sensitive sensors is significantly important for characterizing internal insulation failures and assessing the operational status of SF6 gas-insulated equipment. In this paper, the adsorption properties of GeP3 monolayers for SO2, H2S, SOF2 and SO2F2 gases were investigated based on density functional theory. Four gas adsorption systems were constructed, and the adsorption mechanisms and sensing characteristics of GeP3 monolayers on target gases were investigated by calculating parameters such as adsorption energy, charge transfer, density of states, and recovery time, along with their potential application as resistive gas sensors and field-effect transistor sensors. It is demonstrated that GeP3 monolayers were suitable for the detection of SO2, H2S, SOF2 and SO2F2 gases, all of which exhibited good chemisorption with adsorption energies of −1.36 eV, −0.78 eV, −1.82 eV and −2.91 eV, respectively. The adsorption of SO2 and H2S is found to cause a significant change in the conductivity of the GeP3 monolayers, and desorption is achieved at the optimal operating temperature in only 54.428 s and 10.686 s, respectively. Also the adsorption of SOF2 and SO2F2 can make the work function of the GeP3 monolayers significantly larger. Consequently, the GeP3 monolayers have the potential to be used as a resistive gas sensor for SO2 and H2S gases, or as a field effect transistor sensor for SOF2 and SO2F2 gases. This study provides theoretical guidance for the development of GeP3-based sensors for monitoring the insulation status and operational conditions of SF6 gas-insulated equipment.

A DFT study of superior adsorbate–surface bonding at Pt-WSe2 vertically aligned heterostructures upon NO2, SO2, CO2, and H2 interactions

This study investigates the potential of platinum (Pt) decorated single-layer WSe2 (Pt-WSe2) monolayers as high-performance gas sensors for NO2, CO2, SO2, and H2 using first-principles calculations. We quantify the impact of Pt placement (basal plane vs. vertical edge) on WSe2’s electronic properties, focusing on changes in bandgap (ΔEg). Pt decoration significantly alters the bandgap, with vertical edge sites (TV-WSe2) exhibiting a drastic reduction (0.062 eV) compared to pristine WSe2 and basal plane decorated structures (TBH: 0.720 eV, TBM: 1.237 eV). This substantial ΔEg reduction in TV-WSe2 suggests a potential enhancement in sensor response. Furthermore, TV-WSe2 displays the strongest binding capacity for all target gases due to a Pt-induced “spillover effect” that elongates adsorbed molecules. Specifically, TV-WSe2 exhibits adsorption energies of − 0.5243 eV (NO2), − 0.5777 eV (CO2), − 0.8391 eV (SO2), and − 0.1261 eV (H2), indicating its enhanced sensitivity. Notably, H2 adsorption on TV-WSe2 shows the highest conductivity modulation, suggesting exceptional H2 sensing capabilities. These findings demonstrate that Pt decoration, particularly along WSe2 vertical edges, significantly enhances gas sensing performance. This paves the way for Pt-WSe2 monolayers as highly selective and sensitive gas sensors for various applications, including environmental monitoring, leak detection, and breath analysis.

High-performance SO2 gas sensor based on MXene/LaFeO3 nanotubes by electrospinning technology

High-performance SO2 gas sensor based on MXene/LaFeO3 nanotubes by electrospinning technology

Layer-tunable synthesis of tetragonal Pr-doped SnO2 nanoplates for enhanced sensitive SO2 sensor

Nowadays SnO2 is widely used in manufacturing gas sensors for the detection of toxic and harmful gases such as SO2. However, SnO2 sensor still has the drawbacks of long recovery/response time and low response value. In this experiment, layer-tunable synthesis of tetragonal Pr-doped SnO2 nanoplates are prepared by a feasible hydrothermal method. Observation at SEM reveals that the layer number increases and the interlayer spacing reduces with the increase of doping ratio of Pr (1, 3, 5 mol%). The gas sensing performance show that the three layer tetragonal structure of 1 mol% Pr-doped SnO2 sample with the extended interlayer spacing exhibits outstanding gas sensing performance to 5 ppm SO2 gas at 300℃, including excellent gas response (Ra/Rg = 2.4), fast gas adsorption and desorption equilibrium (15 s/16 s). This work reveals the significance of the layer number and interlayer spacing on the gas sensing characteristics, and the strategy of Pr dopant will promote the widespread application of SnO2 nanomaterials in SO2 gas sensors to figure out severe environmental problems.

Adsorption of toxic and harmful gas NO2 and SO2 on TM (Fe, Co and Ni) modified ZrSe2 monolayer: A DFT study

Based on density functional theory (DFT), the adsorption properties of ZrSe2 monolayer modified by transition metals (Fe, Co and Ni) to NO2 and SO2 of two harmful gases are predicted in this paper. The calculation results indicate that ZrSe2 monolayer modified by metal atom loading is more stable than that doped by metal atom. Therefore, the adsorption behavior of ZrSe2 modified by metal atom loading on two harmful gases is studied. The results demonstrate that the adsorption energy of ZrSe2 monolayer loaded with metal atoms can be significantly improved the adsorption energy of the system, and the chemical bond and charge transfer between metal atoms and gas molecules are generated, indicating a strong interaction between metal atoms and gas. Besides, NO2 gas adsorption on a substrate loaded with metal atoms is superior than that of SO2 gas. The Ni-ZrSe2 system is suitable for NO2 gas sensor, Fe-ZrSe2 system and Co-ZrSe2 system are suitable for SO2 gas sensor according to the comparison of work function and recovery time of different gas configurations. Taken together, this study will provide new directions and theoretical foundations for possible applications of (Fe, Co and Ni)-ZrSe2 monolayers in sensing and processing NO2 and SO2 gases.

Janus HfSSe monolayer: a promising candidate for SO2 and COCl2 gas sensing

Janus monolayers based on transition metal dichalcogenides have garnered significant interest as potential materials for nano electronic device applications due to their exceptional physical and electronic properties. In this study, we investigate the stability of the Janus HfSSe monolayer using ab initio molecular dynamics simulations and analyze the electronic properties in its pristine state. We then examine the impact of adsorbing toxic gas molecules (AsH3, COCl2, NH3, NO2, and SO2) on the monolayer’s structure and electronic properties, testing their adsorption on different active sites on top of hafnium, selenium, and sulfur. The sensitivity of the gas molecules is quantified in terms of their adsorption energy, with the highest and lowest energies being observed for SO2 (−0.278 eV) and NO2 (−0.095 eV), respectively. Additionally, we calculate other properties such as recovery time, adsorption height, Bader charge, and charge difference density to determine the sensitivity and selectivity of the toxic gas molecules. Our findings suggest that the Janus HfSSe monolayer has the potential to function as SO2 and COCl2 gas sensor due to its high sensitivity for these two gases.

Cr2-modified g-CN interface: A novel gas sensitive material for decomposition products of green insulating gas CF3SO2F

Currently, CF3SO2F shows great potential as a green insulating gas to replace SF6 in the electrical industry to support the dual-carbon program. However, it has the potential to undergo partial discharges and thus decomposition under the operating voltage of the power grid, and the gas-sensitive detection technique is an effective method to diagnose this problem. In this work, the gas-sensitive properties of the Cr2@g-CN interface for each harmful gas molecule were investigated from a microscopic point of view, using the harmful gases (SO2, HF, SO2F2, CF4) that may be produced by CF3SO2F as the detection targets. Then, the performance of Cr2@g-CN interface as a gas sensor material in practical applications was predicted. The final results revealed that the Cr2@g-CN interface is most suitable as a potential gas-sensitive material for SO2 gas sensors. The exploration of humidity effects suggests that Cr2@g-CN remains a promising SO2 gas sensing material for practical applications in specific humidity environments. This work reveals the origin of the excellent properties of Cr2@g-CN as a gas sensor material and provides new ideas for the detection of CF3SO2F decomposition products.

Investigation of the electronic and optical properties of bilayer CdS as a gas sensor: first-principles calculations.

We utilised first-principles computations based on density functional theory to investigate the optical and electronic properties of bilayer CdS before and after the adsorption of gas molecules. Initially, we examined four candidate adsorption sites to determine the best site for adsorbing CO, CO2, SO2, H2S, and SO. In order to achieve the optimal adsorption configurations, we analysed the adsorption energy, distance, and total charge. Our findings reveal that the CdS bilayer forms a unique connection between the O and Cd atoms, as well as the S and Cd atoms, which renders it sensitive to SO2, H2S, and SO through chemical adsorption, and CO and CO2 through strong physical adsorption. The adsorption of gas molecules enhances the optical properties of the CdS bilayer. Consequently, the CdS bilayer proves to be a highly efficient gas sensor for SO2, H2S, and SO gases.

Pt-embedded Janus WSTe monolayer for adsorption and detection of XO2 (X = C, N and S) gases: a first-principles study

For sensing XO2 (X = C, N and S) gas species, this work purposes Pt-embedded WSTe monolayer, and using first-principles theory uncovers related gas adsorption properties and sensing mechanism. Results indicate that Pt-embedding is more energy favourable by replacing Te atom of the Janus WSTe monolayer with the formation energy of −1.78 eV, narrowing the bandgap to 0.926 eV. Besides, the Pt-WSTe monolayer performs weak physisorption upon CO2 with adsorption energy (E ad) of −0.17 eV, while strong chemisorption upon NO2 and SO2 with E ad of −1.43 and −1.17 eV, respectively. The analysis of electronic property uncovers the sensing potential of Pt-WSTe monolayer as a resistance-type NO2 or SO2 gas sensor with higher sensing response upon SO2, and the analysis of work function (WF) uncovers the sensing potential of Pt-WSTe monolayer as a WF-type NO2 or SO2 gas sensor with higher sensing response upon NO2. We are hopeful that the findings in this work can help to explore the possible application of Pt-WSTe monolayer in the gas sensing field and also to make some other explorations on Janus WSTe-based material for gas detections.

In-situ growth of well-ordered ZnO nanowire-networks with interconnected junctions for enhanced SO2 gas sensing properties

SO2 gas sensors based on ZnO nanostructures under wild conditions are used widely yet an insufficient electron transfer channels limit the enhancement of the gas-sensing performance. Herein, we report well-ordered ZnO nanowire-networks with interconnected junctions via a simple solution-processing method by adjustment of additive to produce remarkable SO2 gas-sensing performance: low detection limit of 200 ppb, fast response-recovery speed (102 and 58 s) and high response value (8.28) to 10 ppm SO2 at work temperature of 200 °C. The 3D net-work ZnO arrays with fully interconnected junctions, rich oxygen vacancies, and high conductivity are confirmed. Furthermore, the SO2 gas mechanism related to the interjunctions is also clarified. This research offers a novel strategy for designing high performance ppb-level SO2 gas sensor.

First-principles study on α/β/γ-FeB6 monolayers as potential gas sensor for H2S and SO2.

The adsorptions of toxic gases SO2 and H2S on 2D α/β/γ-FeB6 monolayer were investigated using density functional theory calculations. To analyze the interaction between gas molecule H2S/SO2 and α/β/γ-FeB6 monolayer, we calculated adsorption energy, adsorption distance, Mullikan charge, charge density difference, band structure, the density of states, work function, and theoretical recovery time. The adsorption energies show that H2S/SO2 is chemisorbed on α/β-FeB6 while H2S/SO2 is physiosorbed on γ-FeB6 monolayer. As a result, γ-FeB6 has a short recovery time for H2S (5.71×10-8 s)/SO2 (1.94×10-5 s) due to modest adsorption. Therefore, γ-FeB6 may be a promising candidate for reusable H2S/SO2 sensors at room temperature. Although H2S is chemisorbed on α/β-FeB6, as the working temperature rises to 500 K, the recovery time of α/β-FeB6 for H2S can decrease to 1.13×10-1 s and 2.08×10-1 s, respectively, which are well within the detectable range. So, α/β-FeB6 monolayer also may be a good candidate for H2S gas sensor. Calculations were performed at GGA-PBE/DNP level using the Dmol3 module implemented in the Material Studio 2018 software package.

Adsorption and Sensing of NO2, SO2, and NH3 on a Janus MoSeTe Monolayer Decorated with Transition Metals (Fe, Co, and Ni): A First-Principles Study.

This paper reports the adsorption of toxic gases (NO2, SO2, and NH3) on a MoSeTe structure based on first principles. It was found that the gas (NO2, SO2, and NH3) adsorption on a pure MoSeTe monolayer was weak; however, the adsorption performance of these gas molecules on transition-metal-atom-supported MoSeTe monolayers (TM-MoSeTe) was better than that on pure MoSeTe monolayers. In addition, there was more charge transfer between gas molecules and TM-MoSeTe. By comparing the adsorption energy and charge transfer values, the trend of adsorption energy and charge transfer in the adsorption of NO2 and SO2 was determined to be Fe-MoSeTe > Co-MoSeTe > Ni-MoSeTe. For the adsorption of NH3, the effect trend was as follows: Co-MoSeTe > Ni-MoSeTe > Fe-MoSeTe. Finally, by comparing their response times, the better gas sensor was selected. The Ni-MoSeTe system is suitable for NO2 gas sensors, and the Fe-MoSeTe and Co-MoSeTe systems are suitable for SO2 gas sensors. The Fe-MoSeTe, Co-MoSeTe, and Ni-MoSeTe systems are all suitable for NH3 gas sensors. Janus transition-metal dichalcogenides have the potential to be used as gas-sensing and scavenging materials.

Theoretical study of 2D PbSe/Bi2Se3 heterojunctions as gas sensors for the detection of SO2 and Cl2

In this paper, we construct a two-dimensional PbSe/Bi2Se3 van der Waals heterojunction to study the adsorption of Cl2 and SO2 by this heterojunction. Based on the help of Bader charge, charge density difference diagram, and electron localization function, we find the following conclusions. Among the six configurations, three meet the requirements for semiconductor gas sensor detection materials, namely α-PbSe-Bi2Se3, β-PbSe-Bi2Se3, and Bi2Se3-γ-PbSe. The Bi surface of the configuration α-PbSe-Bi2Se3 does not break the Cl-Cl bond in the Cl2 molecule after the adsorption of Cl2, and the band gap of the adsorbed material is reduced by 73.1%. The band gap of the Pb surface of the α-PbSe-Bi2Se3, β-PbSe-Bi2Se3 and Bi2Se3-γ-PbSe configurations change significantly after the adsorption of SO2, directly changing from a narrow band gap to a metallic material with a low adsorption energy and easy desorption of SO2 from the adsorbed material. Therefore, the two-dimensional PbSe/Bi2Se3 van der Waals heterojunction has the potential to become a core detection material for Cl2 and SO2 gas sensors.

Room-Temperature SO2 Gas Sensing Properties of the Ag@GO Heterogeneous Nanomaterial

The study proposes SO2 gas sensor based on a quartz crystal microbalance (QCM) coated with Ag@GO heterogeneous nanomaterial at room temperature. The heterogeneous nanomaterial was synthesized by hydrothermal method at 160 C for 90 min. The structure and morphological characteristics were analyzed by using field-emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The Ag@GO heterogeneous nanomaterial was dispersed in water and coated on an Au electrode of QCM via spray coating method. The fabricated sensor exhibits a good response to SO2 in the concentration range of 2.5-15 ppm. The highest gas sensitivity of the sensor is 8.98 Hz/ppm corresponding to the adsorbed SO2 mass density of 2.38 μg.cm-2. The gas sensing results indicated that the developed sensor can be applied for monitoring, warning, and controlling SO2 in the environment. Moreover, the gas adsorption properties of Ag@GO nanomaterial can also be considered for a filter to remove toxic gases in respirators and environmental treatment.

Relevance and Reliability of Outdoor SO2 Monitoring in Low-Income Countries Using Low-Cost Sensors

In the Western world, the SO2 concentration in ambient air dropped to low levels, but some emission sources (e.g., merchant ships) and some regions (e.g., low-income countries) still emit substantial amounts of SO2. At those locations, SO2 monitoring is critical. However, low-income countries do not have much access to expensive reference instruments. Low-cost gas sensors might be an alternative, but it is unclear how reliable such measurements are. To evaluate the performance of the low-cost alternative, the same SO2 gas sensor has been subjected to three different calibration methods: (1) low-cost calibration performed in the tropical climate of Cuba; (2) high-end calibration performed in Belgium; (3) a field calibration at an air quality measuring station in Belgium. The first two methods showed similar trends, suggesting that the gas sensor can be calibrated with a low-cost method. The field calibration was hampered by the low SO2 concentrations. For the monitoring campaign in Cienfuegos, Cuba, the low-cost SO2 sensor calibrated by the low-cost method appeared to be sufficiently reliable. The reliability of the sensor increases with the increase in SO2 concentration, so it can be used in Cuba instead of Belgium.

Cu-doped flower-like SnO2 architecture toward promoting SO2 detection: Fast equilibrium and low trace monitoring

Design of practical tin oxide (SnO2) semiconductor gas sensors is fundamental strategy to detect hazardous gases such as SO2. However, challenges remain in the detection of SO2 gas at low concentration and slow equilibrium between gas adsorption and desorption. Herein, the superior performance of nanostructured of Cu-doped flower-like SnO2 architecture via feasible hydrothermal method demonstrated for the detection of SO2 gas at low concentration (1–20 ppm) and fast gas adsorption and desorption equilibrium (14 s) towards 5 ppm SO2. Furthermore, the as fabricated 3 mol% Cu-doped SnO2 shows an outstanding gas response (∼ 4.05–20 ppm SO2) at the working temperature of 300 ℃. The Cu-doping strategy may pave the way to ultrasensitive SO2 gas sensor possessing low trace monitoring and fast equilibrium ability to satisfy the increasing demand for toxic SO2 gas detection.