SF6 Decomposition Research Articles

Favorable Adsorption and Detection Properties of Metal Oxides (NiO and Ag₂O) Modified Janus SnSSe Monolayer Toward SF₆ Decomposition Gases in a Gas-Insulated Equipment

Favorable Adsorption and Detection Properties of Metal Oxides (NiO and Ag₂O) Modified Janus SnSSe Monolayer Toward SF₆ Decomposition Gases in a Gas-Insulated Equipment

The gas-sensing mechanism of Nb2C monolayer for SF6 decomposition based on the DFT study

Abstract During fault analysis of gas-insulated switchgear (GIS), continuous monitoring of the gases produced by the decomposition of SF6 is critical to the safe operation of the equipment. Although a variety of gas detection technologies are currently available on the market, low-power gas detection devices for SF6 decomposition products are still in the development stage, and technological advances in this area are of great significance for improving the reliability of GIS systems. Based on the density functional theory (DFT), the Nb2C crystal surface structure was established and six adsorption structures of SO2, H2S, SOF2, SO2F2, HF and CO gas molecules on Nb2C crystal surface were constructed by geometrical optimization in this paper. The gas-sensitive properties of each adsorption system were explored in terms of adsorption energy, charge transfer, electron density, density of states and recovery time. The results showed that the Nb2C crystal surface was unfit HF and CO gases detection, both of which showed weak physical adsorption; the adsorption energies of SO2, H2S, SOF2, and SO2F2 on the Nb2C crystal surface were −1.846 eV, −1.081 eV, −5.270 eV, and −10.582 eV, respectively, and all of them were strong chemical adsorption. It was further shown by theoretical recovery time calculations that the Nb2C crystal surface can act as SOF2 and SO2F2 gas scavengers, and are able to desorb H2S (4.69 s) and SO2 (2.26 s) gases by appropriately increasing the temperature, but the Nb2C crystal surface is more suitable for use as a low-power gas-sensitive material for H2S gas detection. Therefore, Nb2C is anticipated to be a promising material for high response, low-power consumption and fast recovery for H2S gas detection in SF6 decomposition gas.

Mechanism insights and experimental feasibility of using boron nitride nanocones for rapid adsorption and degradation of SF6 decomposition compounds

Gas-insulated switchgear (GIS) employs sulfur hexafluoride (SF6) as an insulating medium to shield electrical gadget. However, SF6 can decompose under sure situations, generating dangerous sulfur-based totally compounds which include SO2, SOF2, and SO2F2. These byproducts pose enormous dangers to both protection and environmental integrity. Efficiently adsorbing and disposing of those compounds is critical for ensuring operational reliability and reducing environmental dangers. This study investigates the adsorption and degradation mechanisms of SF₆ decomposition compounds (SO₂, SOF₂, and SO₂F₂) on boron nitride nanocones (BNNCs) using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. Our comprehensive analysis covers five distinct systems, exploring individual and combined adsorption scenarios. The findings reveal that the apex of BNNCs plays a crucial role in the adsorption process, showing high efficiency in adsorbing SO₂ (adsorption energy − 1.22 eV) and facilitating the catalytic breakdown of SOF₂ (adsorption energy − 1.57 eV). The positively charged potential at the nanocone’s apex significantly influences the dissociation and subsequent adsorption of fluorine atoms, with an energy barrier for F dissociation at the apex (1.8 kcal/mol) much lower than at the sidewall (5.3 kcal/mol). In gas mixtures, SO₂ preferentially binds to the apex region of BNNCs, with a bond length of approximately 1.38 Å. BNNCs demonstrate superior adsorption capabilities for SO₂ and SOF₂ compared to other boron nitride nanostructures, with adsorption energies up to 89% higher. The electron transfer analysis reveals that BNNC complexes act as potent electron donors, particularly in the case of BNNC@3SO₂F₂. Additionally, BNNCs show significant potential as sensors for detecting SO₂F₂, with a rapid recovery time of 4.67 ps and a notable decrease in the Fermi level energy to -4.97 eV upon adsorption. The study also provides insights into the angular distribution and charge density difference profiles, offering a detailed understanding of the adsorption mechanisms. These findings have important implications for improving the safety and efficiency of gas-insulated switchgear (GIS) and contribute to the development of more effective environmental protection solutions in electrical power systems.

A plasma-catalytic system with MgO/NiO/Ni cathode for SF6 degradation

In this work, a plasma-catalytic system in DC discharge with MgO/NiO/Ni (MNN) cathode is proposed for the degradation of SF6 greenhouse gas. The discharge power with MNN cathode is significantly increased compared with Ni cathode due to its good electron emission characteristics, and an effective and stable SF6 degradation performance is achieved in this multi-needle plate discharge system. Besides, surface discharge occurs on the MNN cathode in addition to the needle tips, which is believed to be conducive to the catalytic decomposition of SF6 on the MgO surface. Nontoxic products of MgF2 and MgSO4 are detected on the MgO layer after discharge from various characterizations (XRD, XPS, FTIR and Raman, etc.), suggesting that there is a series of catalytic reactions between SF6/intermediates and MgO. The addition of appropriate O2 (O2:SF6 = 1:1) in the background is not only conducive to the defluorination decomposition of SF6 in ionization region, but also O atom generated from O2 discharge promotes the formation of MgF2 and MgSO4, thus resulting in an effective SF6 degradation performance. Then, the possible degradation mechanism of SF6 in gas phase and on the MgO layer is discussed and the possible degradation pathways are proposed. This research first demonstrates the effectiveness of enabling degrading SF6 gases in a plasma-catalytic system with MNN cathode.

A DFT study of SF6 decomposition products (H2S, SO2, and CS2) adsorption and detection on Pd-ZnO/SnS2 ternary composites

Real-time and accurate detection of SF6 decomposition products is a crucial approach to diagnosing internal faults of gas-insulated switchgear (GIS). However, the limited sensitivity and selectivity of SnS2 gas sensors have hindered their further development and application. This study employs density functional theory to design the optimal Pd-ZnO/SnS2 monolayer structure and investigate its adsorption behavior toward H2S, SO2, and CS2. The findings indicate that Pd atom doping and ZnO nanoparticle incorporation significantly enhance the conductivity of the SnS2 monolayer, reducing the band gap to 0.54 eV and lowering the work function by 5.019 eV. Regarding gas adsorption and sensing, the Pd-ZnO/SnS2 monolayer outperforms intrinsic SnS2 and ZnO/SnS2, showing the order in which SF6 decomposition products are selected is: CS2 > SO2 > H2S. Additionally, the sensitivity and recovery time of Pd-ZnO/SnS2 as a gas sensor were evaluated, confirming its excellent sensing performance for SO2 and CS2 detection. This study provides theoretical insights to advance the application of gas sensors in online insulation equipment monitoring.

Parameter Optimization of Semiconductor Gas Sensor under AC Impedance Measurement.

Semiconductor gas sensors were confirmed to perform high linearity and a stable baseline under alternating current (AC) impedance measurements. However, a procedure to determine the optimal parameters of AC impedance measurements is still lacking. Taking the detection of SF6 decomposition gas as an example, this work has established a model of semiconductor gas sensors under AC impedance measurement. Employing four types of sensors to detect three gases (H2S, SO2, and CO), the effectiveness of the optimization method has been validated, as well. With the high linearity and stable baseline obtained from AC impedance measurement, it enables rapid correction of temperature drift within environmental temperatures ranging from 10 to 30 °C. Overall, the proposed method can provide a novel approach to inhibit the drift failure of semiconductor gas sensors.

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.

Adsorption behavior of SF6 partial discharge decomposition components on metal (Pt, Pd) modified ZnO surfaces

High-voltage SF6 gas-insulated equipment generates various characteristic gas components during partial discharge faults, threatening the equipment’s normal operation. Based on density functional theory, this study investigates the adsorption behaviors of H2S, SO2, SO2F2, and SOF2 on ZnO bilayers before and after Pt/Pd modification. Analysis of adsorption energy, density of states, conductivity, and recovery time reveals that the adsorption effectiveness of ZnO bilayer on SF6 decomposition components is H2S > SO2 > SOF2 > SO2F2. Pt/Pd doping significantly reduces the adsorption energy of gas molecules on ZnO surfaces but does not alter the adsorption effectiveness. Additionally, considering the significant changes in Pt/PdZnO’s conductivity after adsorption of specific gas molecules, PtZnO is suitable as a sensor material for H2S, SO2, and SO2F2, while PdZnO is suitable for SO2 sensing. This study provides a theoretical foundation for developing novel sensor materials for SF6 decomposition components, potentially enhancing electrical equipment’s economic and operational safety.

Adsorption and sensing properties of TiO2-modified MoSe2 monolayer for SF6 decomposition components based on the first-principles

As crucial components in power systems, SF6 gas-insulated equipment inevitably develops insulation defects and faults over long-term operation, leading to the decomposition of SF6 gas. Therefore, detecting SF6 decomposition components is essential for assessing the operational status of SF6 gas-insulated equipment and ensuring the safe and stable operation of power systems. Based on first principles, the modification mechanism of TiO2 on MoSe2 was explored, and optimal adsorption models for gases SO2, H2S, SOF2, and SO2F2 on this composite material were established. The adsorption characteristics of each system were analyzed through parameters such as adsorption energy, adsorption distance, charge transfer, electron density difference, and density of states, and the sensing properties of the systems were discussed using parameters including changes in frontier molecular orbitals, desorption time, and sensitivity. The results indicate that TiO2–MoSe2 has difficulty capturing SO2F2, but exhibits chemisorption for SO2, H2S, and SOF2 with adsorption energies of −1.25 eV, −0.99 eV, and −3.40 eV, respectively. Upon adsorption of SO2, TiO2–MoSe2 shows a significant change in electrical conductivity, a desorption time of 4.51 s (at 498 K), and a strong sensitivity response. However, the response to H2S is relatively weak, with lower sensitivity. Therefore, this material is suitable for detecting SO2 but not H2S. TiO2–MoSe2 demonstrates a significant response and excellent sensitivity to SOF2; however, the adsorption process lacks repeatability. Therefore, it can be used as a disposable gas sensor or solid adsorbent for SOF2 detection. The results of this study provide theoretical support for the application of MoSe2-based sensors in the monitoring and fault diagnosis of SF6 gas-insulated equipment.

Dual-species sensor using time-division multiplexed laser absorption spectroscopy for hydrogen sulfide and carbon monoxide measurement in SF6 insulated equipment fault detection

To address the issues of high detection limits, long response times, and susceptibility to cross-interference in the detection of characteristic gases CO and H2S produced by SF6 electrical equipment failures, a dual-species laser sensor prototype for SF6 decomposition products in electrical equipment was developed based on tunable diode laser absorption spectroscopy (TDLAS). The absorption lines of 2334 nm and 1576 nm were selected for CO and H2S, respectively. The concentration inversion was performed using wavelength modulation spectroscopy (WMS) with first harmonic normalization of the second harmonic. The experimental results demonstrate that a rapid response time of ∼30 s is achieved and the sensor has detection accuracies of 0.59 % for CO and 2.09 % for H2S, with minimum detection limits of 0.46 ppb and 14.00 ppb, respectively. The dual-species laser sensor allows for convenient, rapid, and precise detection of CO and H2S, showing promising application prospects in electrical environment monitoring.

DFT study of Cun (n = 1–3) cluster-modified WSe2 monolayers for the detection of SF6 decomposition gases (H2S, SO2, SOF2 and SO2F2)

The role of SF6 in gas-insulated equipment is crucial for insulation and arc extinction. When subjected to electrical faults, thermal faults, and mechanical failures in insulation devices, SF6 can decompose into H2S, SO2, SOF2, and SO2F2. This study conducted first-principles simulations to analyze the effect of Cun (n = 1–3) cluster-modified monolayer WSe2 on sensing H2S, SO2, SOF2, and SO2F2 gases during SF6 decomposition. The optimal doping positions of Cun-WSe2 clusters at n = 1, 2, and 3 were determined, showcasing their superiority over pure WSe2 in terms of band gap, frontier orbitals, and density of states. Subsequently, a detailed investigation was carried out on the adsorption effects of the four gases at the optimal doping positions, including parameters such as adsorption distance, adsorption energy, charge transfer, differential charge density, and density of states. It was found that when the number of copper atoms in the cluster increased to 3, the banding energy sharply rose to -2.395 eV. Simulation results demonstrated the adsorption behavior of H2S on Cun (n = 1–3)-WSe2 demonstrates remarkable affinity, with an increasing adsorption energy as the number of Cu atoms rises. Notably, Cun (n = 1–3)-WSe2 exhibits favorable desorption times for SO2. At 378 K, the desorption time for SO2@Cu3-WSe2 is 14.7 s. At 498 K, desorption times for SO2@Cu1-WSe2 and SO2@Cu2-WSe2 are 7.59 s and 2.85 s, respectively. When the number of copper atoms is 2, the cluster-modified system desorbs SOF2 at room temperature in only 0.89 s. Moreover, Cun (n = 1–3)-WSe2 displays strong adsorption towards SO2F2, characterized by prolonged desorption times, rendering it a promising adsorbent for SO2F2 removal. This study aims to highlight the adsorption effects of different numbers of Cu atomic clusters in the Cun-WSe2 system on SF6 decomposition gas, further advancing research for developing high-performance SF6 decomposition gas sensors.

Gas-Sensing Performance of Metal Oxide Heterojunction Materials for SF6 Decomposition Gases: A DFT Study.

The online monitoring of GIS equipment can be realized through detecting SF6 decomposition gasses. Metal oxide heterojunctions are widely used as gas-sensing materials. In this study, the structural and electrical properties of In2O3-ZnO and TiO2-ZnO heterojunctions were analyzed based on density functional theory calculations. After heterojunction structural optimization, the electrical conductivity of these two heterojunctions was enhanced compared to each intrinsic model, and the electrical conductivity is ranked as follows: In2O3-ZnO heterojunction > TiO2-ZnO heterojunction. The gas-sensing response of these two heterojunctions to four SF6 decomposition gasses, H2S, SO2, SOF2, and SO2F2, was investigated. For gas adsorption systems, the adsorption energy, charge transfer, density of states, charge difference density, and frontier molecular orbitals were calculated to analyze the adsorption and gas-sensing performance. For gas adsorption on the In2O3-ZnO heterojunction surface, the induced conductivity changes are in the following order: H2S > SO2F2 > SOF2 > SO2. For gas adsorption on the TiO2-ZnO heterojunction surface, H2S and SOF2 increase conductivity, and SO2 and SO2F2 decrease conductivity.

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.

Density-functional theory study of SnSe/GeSe heterostructure for gaseous sulfur hexafluoride decomposition products sensing

Partial discharge, local overheating and other factors will lead to the decomposition of superior dielectric gas sulfur hexafluoride (SF6) used in gas insulated substations (GIS). Detecting gaseous sulfur hexafluoride (SF6) decomposition products by gas sensors to diagnose early latent insulation failures is a potential approach to guarantee safety and reliability of gas insulated substations (GIS). However, the main difficulties in the detection of SF6 decomposition products lie in sensitivity, operating temperature and sulfur poisoning of the sensor. Metal oxide selenides (MOSs)-based gas sensors suffer from high working temperature, long recovery time, and sulfur poisoning. Two dimensional selenides-based chemiresistor-type gas sensors have been reported to detect certain gases at room temperature. Compared with pristine materials, heterostructures usually have narrower band gaps and higher carrier mobility which promise low power and sensitivity. In this work, a SnSe/GeSe van der Waals heterostructure model is constructed and optimized to investigate the gas sensing properties by density functional theory (DFT) calculations. Compared with the pristine SnSe and the pristine GeSe, the SnSe/GeSe heterostructure exhibits huge adsorption energy and comparatively large charge transfer to the SF6 decomposition gases. The band structure analysis, charge analysis, electron localization function (ELF), and density of states (DOS) analysis suggest that the excellent sensing properties are contributed to the synergistic effect between the SnSe and the GeSe layers: both the layers transfer charge and orbitally interact with gas molecules. Besides, physical adsorption of the SF6 decomposition gases on SnSe/GeSe heterostructure avoids sulfur poisoning of the material, promising the recoverability and repeatability of detection. This study provides theoretical bases for the repeatable detection of SF6 decomposition products by SnSe/GeSe heterostructures and its potential in the design of electronic nose.

AlC3 monolayer: Highly responsive and selective gas sensing material for SF6 decomposed gases (SOF2, SO2F2 and SO2)

Sulfur hexafluoride (SF6) is widely employed in industrial applications due to its interesting insulating properties. However, under electrical discharge conditions, it can undergo decomposition, yielding hazardous gases such as SOF2, SO2F2, and SO2, which can pose significant risks due to their increased toxicity and corrosive nature, affecting human health, the environment, and equipments. In this investigation, we employed density functional theory and ab-initio molecular dynamics to evaluate the stability of AlC3 monolayer and investigate its sensing capabilities. The findings establish the AlC3 monolayer as a champion material for detecting SF6 decomposition gases, specifically SOF2, SO2F2, and SO2. Importantly, the AlC3 monolayer exhibited low sensitivity to humidity and other gases, including CO2, CO, HF, H2, HCN, and H2S, highlighting its exceptional selectivity. SO2F2 exhibited the substantial adsorption energy of −1.36 eV, a work function of 5.2 eV, and a −0.69e charge transfer. Similarly, SO2 and SOF2 displayed significant adsorption energy (-1.19 eV and −1.08 eV, respectively), work functions (4.55 eV and 4.81 eV), and charge transfers (-0.61e and 0.78e). The significant variation in work function upon SO2F2 adsorption indicates the AlC3 monolayer's potential selectivity for SO2F2 over SO2 and SOF2, making it a promising material for surface work function modulated transistors. Ab-initio molecular dynamics simulations confirm AlC3 monolayer stability after adsorption at 300 K, validating predicted positions by density functional theory.

Two-dimensional Mo3-TiS2 monolayer hosting high moisture resistance and abundant surface-chemisorbed oxygen for effective detection of SF6 decomposition gases: Atomic-scale study

Monitoring the SF6 decomposition gas (DPA) by gas sensors can be used to predict the operating status of power equipment, and the sensitivity performance of gas sensors is deeply influenced by the humidity resistance and surface oxygen adsorption performance of their sensing materials. The present research aims to explore a high‐valence transition‐metal ion doped transition metal dichalcogenide (TMD) monolayer that hosts high moisture resistance and abundant surface-chemisorbed oxygen suitable for detecting DPA. Using first-principles methods, the adsorption behavior of three representative types of gases (HF, SO2, and CO2) in DPA, H2O, and O2 on Mo3-TiS2 monolayer are considered. Our results show that SO2 and CO2 molecules are adsorbed above the Mo3 cluster through chemical adsorption, while HF molecule is physically adsorbed. The desorption times for SO2 and CO2 on Mo3-TiS2 adsorbent are 9.89 s at 348 K and 34.96 s at 398 K, respectively. Introducing dopant Mo3 resulted in better anti-humidity performance of TiS2, as the force of Mo3-TiS2 monolayer towards H2O molecule is weakened compared to the intrinsic adsorption system. Additionally, Mo3-TiS2 monolayer exhibits an exceptionally high affinity for O2 molecule, leading to the rupture of chemical bond in O2, and the chemisorbed oxygen ions are acquired through the charge transfer between Mo3 cluster and O2 molecule. The computational findings in this article offer theoretical backing for advancing the development of gas sensors utilizing Mo3-TiS2 and its utilization in the realm of DPA detection.

Adsorption of SF6 decomposition gases (SO2 and SOF2) onto pristine and transition metal modified WSe2 monolayers: A systematic DFT study

The properties of SF6 characteristic decomposition products (SO2 and SOF2) adsorbed on intrinsic and transition metal atom modified WSe2 monolayers were studied based on the first principles. The adsorption structure, adsorption energy, electron transfer, density of states, electron differential density, work function, and desorption properties are comprehensively discussed. In addition, the charge transfer in the adsorption system was qualitatively analyzed by using the frontier molecular orbital theory and energy band. The results show that the pristine WSe2 monolayer has poor sensing performance for SO2 and SOF2. Effective modification methods can significantly increase the adsorption activity of the monolayer surface. The modification methods of transition metal atom adsorption and doping are discussed respectively. The modified monolayer all exhibit good sensing properties compared to the pristine monolayer due to the significant electronic hybridization between the impurity atoms and the gas molecules. Finally, the recovery response time of gas molecules from transition metal atom modified WSe2 monolayer is evaluated to evaluate its potential application in the detection and removal of fault gases in SF6 insulation equipment. Our work is not only important for predicting novel transition metal sulfide sensing materials, but also provides theoretical guidance for further developing WSe2-based sensors and scavengers for environmental monitoring applications.

Theoretical study of the adsorption properties of transition metal atom-doped monolayer GeSe materials for SF6 decomposition components

The insulating gas SF6 will decompose and generate a series of by-products under fault conditions, affecting the power equipment's stable operation. In this paper, the adsorption characteristics of the two-dimensional material GeSe and doped with transition metal(TM) on SF6 decomposition gases HF, CS2, and SO2F2, including adsorption energy, charge transfer, density of states, and differential charge density, are investigated based on the First-principles, and their potentials to be used as a gas-sensitive material for monitoring SF6 decomposition are analyzed based on theoretical response heights and recovery times. The results show that the doping of TM atoms enhances the adsorption capacity of GeSe materials for SF6 decomposition components, in which Co-GeSe materials can be used to monitor the production of CS2 gas molecules. In contrast, Mn-GeSe materials have a promising prospect as adsorbents for SO2F2.

Ultrasensitive detection and sensitivity mechanism of SO2F2 in SF6 decomposition product based on TiO2-NiS heterojunction

SO2F2 is a typical fault product of SF6 electrical insulation equipment. Detecting SO2F2 can indicate whether the equipment is faulty. SO2F2 is a hazardous gas that can cause harm to the human body. This study reports on the development of the SO2F2 sensor using TiO2-NiS for the first time, and the investigation of its gas sensitivity to SO2F2 in SF6 background and air. The effective construction of the TiO2-NiS heterojunction was characterized via the XRD, SEM, and TEM. The TiO2-NiS heterojunction sensor for SO2F2 has a working temperature of 150°C in both SF6 and air environments with the response and recovery time of 6 s/2 s to 5 ppm SO2F2 in the air and 5 s/6 s in the SF6 environments, respectively. The sensor has a strong linear fit and a detection limit of 100 ppb. The long-term stability, selectivity, resistance to moisture, and responsiveness/recovery are features of this sensor. Furthermore, it was demonstrated that SO2F2 adsorption performance on the TiO2-NiS heterojunction outperformed that of TiO2 and NiS based on first principles, and density of states and differential charge density provided a more detailed description of the interaction between SO2F2 gas and the TiO2-NiS heterojunction. The oxygen competitive adsorption of SO2F2 and lattice oxygen molecules on the surface of TiO2-NiS heterojunction, as well as the interaction between adsorbed F2− on the TiO2-NiS heterojunction surface and SO2F2, may be used to characterise the sensing mechanism in the SF6. At the same time, the prepared SO2F2 sensor can effectively measure the concentration of SO2F2 through hardware, and give early warning when the concentration exceeds the safe value.

Computational exploration of SF6 adsorption and decomposition on SiGe and calcium-decorated SiGe surfaces

Computational exploration of SF6 adsorption and decomposition on SiGe and calcium-decorated SiGe surfaces