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Context: SF6 gas has a strong greenhouse effect, and how to treat SF6 in an environmentally friendly way has been a hot topic of current research. In this paper, the adsorption behavior of SF6 on the surface of Pd-doped hydroxyl-terminated modified Ti3C2Tx (i.e., Ti3C2(OH)2) was investigated based on the density functional theory using two-dimensional MXene as the catalyst. The structures of different Pd-doped Ti3C2(OH)2 were analyzed and the most structurally stable doped structures were selected as the basis for subsequent calculations. A large number of adsorption configurations were constructed and geometrically optimized, and the adsorption energy, charge transfer, differential charge density, and density of states of the systems were calculated in order to analyze the gas–solid interactions and find the surface active sites; compared with the adsorption performance of undoped Ti3C2(OH)2 on SF6, it was found that Pd doping played a less inhibitory role in the adsorption of SF6 on the Ti3C2(OH)2 surface. The results of this study can provide theoretical support for the use of Pd-doped Ti3C2(OH)2 as a catalyst for the degradation of SF6. Methods: In this paper, simulations of SF6 adsorption on Ti3C2Tx surfaces are based on density functional theory and are carried out in the Dmol3 module of Material Studio. To better describe the non-uniform electron density of the actual system, the PBE functional in the generalized gradient approximation (GGA) was chosen for the optimization of the structure of the gas–solid interface system and the calculation of the relevant electronic properties, combined with the Grimme dispersion correction in the DFT-D dispersion correction for the electron exchange correlation term. Because both Pd and Ti are transition metal elements, the mode-conserving pseudopotential DNP basis set containing relativistic effects was chosen for the electronic wave function expansion. In this paper, an all-electron model is used for the inner core treatment of gas molecules and a density generalized semi-nuclear pseudopotential DSSP is used for the solid surface treatment. [ABSTRACT FROM AUTHOR]

In gas-insulated equipment, the decomposition of SF6 is closely related to the residual traces of O2 and H2O in the equipment. However, the decomposition mechanism has not yet been clarified. In this paper, the adsorption and defluorination of SF6 on the preadsorbed Cu(111) surface were calculated based on density flooding theory and transition state theory. Besides, the influence mechanism of O atoms and H2O molecules on the defluorination process is analyzed by comparing the energy barrier, reaction heat, and density of states. The results show that pre-adsorption of O atoms changes the adsorption sites of SFx, but has no significant effect on the adsorption energy. In addition, the O atom has a certain inhibitory effect on the decomposition process, and SF → S + F is the key to determining the reaction rate. In contrast, H2O will not only promote the adsorption of SFx to the surface but also reduce the total reaction heat of the decomposition reaction by 135.37 kcal·mol−1, driving the decomposition process of SF6. In this paper, stable co-adsorption configurations of low-fluorosulfide and co-adsorption groups were determined, and the effects of O and H2O preadsorption on SF6/Cu gas–solid interactions were initially revealed. [ABSTRACT FROM AUTHOR]

Accurately grasping the decomposition path of SF6 on the surface of typical metals and metal oxides is the key to reveal the decomposition mechanism of overheating fault. In this paper, the decomposition paths of SF6 on Cu and its oxides are theoretically analyzed by combining density functional theory and transition state theory. The results show that the participation of Cu surface reduces the energy required for the initial decomposition of SF6 by about 98.70 kcal/mol compared to that in free space. The decomposition reaction of SF5 on the Cu surface is energy barrier free, thus SF5 cannot stably exist in SF6 over-thermal decomposition system. Further, it was found that when Cu was oxidized at high temperature, reactions between SF6 and metal surface would be more intense. At this time, the total reaction heat of SF6 completely decomposed into S was -220.07 kcal/mol, significantly lower than -100.60 kcal/mol on Cu surface. This illustrates the catalytic effect of Cu and its oxides. On the surface of CuO, the interaction of O and F atoms may be the main reason to further reduce the activation energy. This article explained the over-thermal decomposition process of SF6 from microscopic level, laying a theoretical foundation for further study on the influence of the over-thermal decomposition of SF6-metal system. [ABSTRACT FROM AUTHOR]

In gas-insulated equipment, partial over-thermal faults may occur due to poor contact and other reasons. The main insulation medium SF6 may decompose under over-thermal conditions and produce harmful products such as SO2 and HF, which can damage the equipment and reduce the insulation strength of the equipment. The method of decomposition component analysis can monitor the operating status of equipment without interference from machinery, noise and optics, and provide early warning or reminder of faults, but the premise is that the decomposition mechanism of SF6 must have been fully and in-depth understood. In the decomposition process of SF6, O2 has a significant effect, but the mechanism of the effect is still unclear. Based on the isotope tracing method, this paper uses 18O2 instead of ordinary O2 for overheating experiments. Through the quantitative detection of the labeled products in the product and the abundance of 18O isotope in the products, the effect of O2 on the formation of the main decomposition products was analyzed. The work makes the reaction process and mechanism of SF6 with trace oxygen under over-thermal conditions basically clear, which provides an important theoretical basis for on-line monitoring and fault diagnosis of equipment based on chemical analysis methods. [ABSTRACT FROM AUTHOR]

Poor contact is one of the main causes of the internal fault of SF6 gas insulated equipment. Taking the most common over-thermal decomposition process of SF6 caused by poor silver-plated copper contacts as an example, this article combines with density functional theory (DFT) and establishes the gas–solid contact interface adsorption model of SF6 and its main decomposition characteristic products (SO2F2, SO2, SOF2, HF, and H2S) with solid silver. Adsorption energy, charge transfer, and density of electronic state were used to analyze the reaction activity of SF6 and its main decomposition products with the Ag surface. It is found that SF6 and SO2 are chemically adsorbed on the Ag surface, and the reaction activity is relatively strong. When chemical adsorption occurs, SF6 bonds with the metal surface by the 2p orbitals of F atoms, and SO2 is bonded to the metal surface by the 2p orbitals of O atoms. There is also a strong reaction trend between HF and Ag (1 1 1), while SO2F2, SOF2, and H2S only physically absorbed with the Ag (1 1 1) surface. This indicates that under the local overheating failure caused by metal contacts, SF6 will first undergo chemical adsorption in the SF6/Ag (1 1 1) system and then undergo a decomposition reaction near the metal surface rather than in free space. The participation of Ag reduces the difficulty of the decomposition reaction to some extent. The results lay a foundation for finally revealing the interfacial reaction process of SF6-Ag. [ABSTRACT FROM AUTHOR]

To investigate the difference between the sulfur hexafluoride (SF6) decomposition characteristics initiated by two sorts of insulation defects — free metal particles and metal protrusion defects — under negative DC partial discharge (PD), SF6 decomposition data was obtained under different DC voltages on the basis of constructing a SF6 decomposition experimental platform. The differences between the characteristic components and the characteristic ratios of the two defects at the same discharge quantity and voltage were systematically analyzed. Results show that the two defects have significant differences in the type of decomposition components, the yield sizes of the components, and the changes in the component ratios. This paper proposed c(CF4 + CS2)/c(CO2) and c(CF4)/c(SO2F2) as the characteristic ratios to characterize the fault severity of the two defects, and their physical nature were revealed. The combination of the above ratios with the existing c(SO2F2)/c(SOF2 + SO2) can construct a feature quantity for identifying the two defects. [ABSTRACT FROM AUTHOR]

To study the correlation characteristics between SF6 decomposition components and discharge strength under negative DC partial discharge (PD) initiated by free metal particle defect, SF6 decomposition data were obtained under different voltages on the basis of constructing SF6 decomposition experimental platform. The variation law of SF6 decomposition components and characteristic ratios were systematically analyzed. The study shows that SF6 decomposes into CO2, SO2F2, SOF2, SO2, CF4, and a very small amount of CS2 under PD. The SOF2 concentration and its formation rate have the highest correlation with the PD discharge quantity among all components. The yield relationship of decomposition components is different at different discharge quantities. In addition, the fluctuation of each characteristic ratio is small after 72 h and can achieve a certain degree of steady state. c(CF4+CS2)/c(CO2) and the proposed c(SO2)/c(SO2F2) can be used as the fault severity characteristic ratio in free metal particle defect. [ABSTRACT FROM PUBLISHER]

Aimed to clarify the correlation characteristics between the internal partial discharge (PD) in the negative direct current (DC) gas‐insulated system (GIS) and gas pressure, and to establish an insulation fault diagnosis method based on decomposition component analysis, this study on PD decomposition of sulphur hexafluoride (SF6) was conducted under different pressures on the basis of constructing a SF6 decomposition experimental platform under DC PD. A stainless steel needle‐plate electrode was used to simulate the insulation defects of metal protrusions in GIS. SOF2, SO2 F2, CO2, SO2, and CF4 data generated from SF6 decomposition were obtained under different pressures. The variation law of component concentration and effective characteristic ratio with pressure were analysed in detail. In addition, a mathematical formula for pressure and decomposition components was deduced according to gas micro‐ionisation theory. The effective content and formation rate were defined to validate the relationship. Results show that the concentration of SF6 decomposition components decreased gradually with increasing pressure with a strong regularity. Furthermore, the relationship between pressure and component concentration derived from the theory can explain the relationship between the effective content of SF6 decomposition components and the effective formation rate and pressure variations. [ABSTRACT FROM AUTHOR]

The decomposition characteristics of SF6 gas-insulated equipment remarkably vary under different working pressures (0.3?0.7 MPa). Thus, the influence of pressure should be considered when adopting decomposed components for spark discharge fault diagnosis. A series of experiments on SF6 spark discharge decomposition under various pressures were performed on the spark discharge simulation experimental platform. The influence of pressure on SF6 spark discharge decomposed components were analyzed quantitatively combined with molecule chemical decomposition mechanisms. Results show that the species of spark decomposed components do not vary under different pressures. However, pressure directly affects the accumulated energy of the electrons in the spark channel, leading to diverse dissociation intensities of electrons on SF6. This phenomenon further affects the rate of neutral-neutral molecule and ion-molecule reactions responsible for the decomposed components. Finally, the yields and effective generation rates of decomposed components CF4, SOF4, SO2F2, SOF2, and SO2 decline with varying degrees under increasing pressure. Moreover, mathematic regression equations were derived for the effective generation rates of the components influenced by pressure. [ABSTRACT FROM AUTHOR]

To figure out the influence rules of trace H2O on SF6 decomposition characteristic components under spark discharge, a series of spark discharge decomposition experiments with various H2O contents were performed using needle-plate electrode to simulate metal protrusion insulation defect. The changing rules and mechanisms of five decomposition characteristic components were achieved quantitatively, indicating that no matter how much H2O was, there exist five main decomposition components: CF4, SOF2, SO2, SOF4 and SO2F2. The contents of the five decomposition components increased with the time extended, and resulting in the contents of SF6 spark decomposition components by the order: SOF2 > SO2F2 > SOF4 > SO2 > CF4. Additionally, the higher H2O content is, the stronger promoting effect on the generation of SO2F2, SOF2, SOF4 and SO2 is. [ABSTRACT FROM AUTHOR]

Photoacoustic (PA) spectrum is a promising method in SF6 decomposition product detection. To develop an on-line monitoring device, a gas detection system based on PA effect was introduced. Three kinds of gases, SO2, CO2, and CF4, were chosen to test the device performance. Some experiments were conducted to get the relationship of PA signal and gas concentration. The minimum detection limit of each gas was also measured. After that, the influence of temperature on PA detection was studied under 30 °C−50 °C. It is found that the PA signals of SO2 (1360 cm ^-1 ), CO2 (2347 cm ^-1 ), and CF4 (1285 cm ^-1 ) all have negative temperature characteristics within that temperature range. Then, a temperature linear correction model was proposed. The maximum error between correction result and standard PA signal under reference temperature was <4%. The temperature correction method lays a foundation for manufacturing SF6 decomposition components on-line monitoring device. [ABSTRACT FROM PUBLISHER]

We explored the thermal decomposition characteristics of SF6 with partial overthermal fault in organic solid insulating materials. Results show that when organic solid insulating materials were around the fault point, the main overthermal decomposition characteristic products of SF6 were CS2, CO2, CF4, H2S, SO2F2, SOF2, and SO2. The difference in the generating reaction and degree of reaction of the seven decomposition components resulted in the complexity of concentration and growth regularity. Surface component analysis after the experiment showed that the thermode surface contained numerous S, O, C and F. Fe existed in the form of Fe2O3 and FeF2. The organic insulating materials added new elements, such as F and S, because HF and H2S easily reacted with O in the epoxy group. [ABSTRACT FROM AUTHOR]

Sulfur hexafluoride (SF₆) gas-insulated equipment (GIE) has been widely used in extra/ultra high voltage power transmission systems. During its operation, GIE inevitably experiences partial overthermal faults caused by poor contact. In this study, the SF₆ decomposition characteristic of partial overthermal faults was used to solve problems that cannot be detected effectively in GIE. First, a large number of experiments were conducted on an SF₆ overthermal decomposition system to obtain the overthermal decomposition characteristic of SF₆ below 400 °C. Then, from the perspective of the physical significance of engineering, three feature parameters, namely, total decomposition amount, effective formation rate, and ratio of characteristic components, were proposed to reveal the deterioration degree of the gas insulation medium as well as to represent the development trend and severity of a partial overthermal fault. Results show that total decomposition amount CT, CT1, and CT2 can depict the degradation degree of the GIE insulation medium and the carbonic metal structure caused by a partial overthermal fault, which can be a good index to differentiate partial overthermal fault temperatures. The effective formation rate of each characteristic component RRMS is closely related to temperature and can reflect the development trend of a partial overthermal fault. The feature ratio CO2/(SO₂F₂+SOF₄+SOF₂+SO₂+H2S) can reveal whether a partial overthermal fault involves organic insulation materials. H2S/(SO₂F₂+SOF₄) can depict the severity of a partial overthermal fault. Log10(SOF₂+SO₂)/(SO₂F₂+SOF₄) and its effective value TCRRMS3 can represent the deterioration degree of GIE and provide excellent correlation with the severity of a partial overthermal fault, and thus, it can be used to evaluate the severity of a partial overthermal fault quantitatively. [ABSTRACT FROM PUBLISHER]

This study examines how byproducts from thermal decomposition of sulfur fluoride (SF6) can be measured and applied to diagnose an overheating fault occurring in SF6 insulated equipment. Using a series of experiments performed on a SF6 thermal fault simulation system, the thermal decomposition characteristics of SF6 were obtained for temperatures below 400°C. Based on these results, the formation rate was extracted to indicate the progress of the thermal fault's development, and the characteristic component ratio was used to identify the type and severity of the thermal fault. The relationship of the fault temperature and the formation rate along with the correlation between the characteristic ratio and the fault temperature were studied. The results show that: the formation rate of the components effectively reflects the severity and development trend of the thermal fault; by integrating the IEC standard 60480‐2004, the obtained thermal fault maximum safe time (TMS) can accurately indicate the largest safe time when thermal fault happens; component characteristic ratios C(SO2)/C(SO2F2) and C(SO2F2+SOF4)/C(SOF2) can be used to evaluate whether the fault type is a thermal fault; and the thermal correlation ratio (TR) can be employed to recognize the temperature value from 300°C to 400°C. [ABSTRACT FROM AUTHOR]

To explore the influence mechanism of trace H2O on SF6 decomposition characteristics under partial thermal fault and establish the foundation of using SF6 thermal decomposition principle to diagnose the thermal fault of SF6 electrical equipment, a series of artificial thermal fault decomposition experiments with different H2O concentrations were conducted on the designed SF6 thermal decomposition experimental system. A trace water injector was used to control the content of trace H2O accurately and gas chromatograph, chromatography-mass spectrometry as well as Fourier transform infrared spectroscopy were used to measure decomposed components. Finally, the thermal decomposition characteristic under 340 ° was achieved. The analysis results indicate no matter how much H2O content is, SF6 can decomposes into many kinds of decomposition characteristics, such as CO2, SOF2, SO2, SOF4, SO2F2, H2S, HF. The concentrations of all these decomposition characteristics increase with the time extended, but change differently with the increase of H2O content, because H2O plays different role in the formation process of each decomposition characteristic components. The variation of H2O content not only affects the production of the decomposition characteristic components, but also makes SO2 and HF gradually evolved into the main characteristic components of SF6 thermal decomposition. In addition, the higher the H2O content is, the stronger the promoting effect on SO2 and HF is. [ABSTRACT FROM AUTHOR]

SF6 decomposition characteristics under partial discharge (PD) are not only associated with insulation fault type and its severity but also closely related to the H2O content of in the equipment. This paper studies the decomposition characteristics of mixture gas SF6/H2O with six different gradients of trace H2O under the same PD energy, selects SO2F2, SOF2, CO2, and CF4 as the characteristic components, and analyzes the influence regularity of trace H2O on each of the component concentration, effective formation rate and characteristic ratio. Results show that H2O creates favorable conditions for generating SO2F2 and SOF2 owing to the capacity to capture F atom and inhibit low fluorine sulfides from recombining into SF6. As a result, the concentration and effective formation rate of SO2F2 and SOF2is positively related with H2O. Whereas H2O has no evident influence on CO2, it can consume intermediate by-products CF2 and CF3 which restrain CF4 generation. Each characteristic ratio decreases sharply and then becomes stable with increment of H2O. The defined effective characteristic ratio effectively reflects its relationship with H2O, whereas obtained mathematical expression between each effective characteristic ratio and trace H2O lays solid foundation for fault diagnosis of SF6 insulated equipment based on SF62 decomposition characteristics. [ABSTRACT FROM AUTHOR]

To obtain the influence regularity of trace O2 on SF6 decomposition characteristics under partial discharge (PD) and establish the foundation of using SF6 decomposed components to diagnose the insulation status of SF6 electrical equipment, first, a series of PD decomposition experiments with different O2 concentrations (%)were conducted on a special experiment platform. The variation regularity between the concentrations of characteristic components and the different content of O2 were obtained quantitatively. Second, the correlation coefficient r testing method was applied to identify the associated influence of trace O2 on the decomposed characteristic components and characteristic ratios. Based on this, an exponential regression model of the related characteristics was developed. Finally, the influence mechanism of trace O2 on SF6 decomposition progress was explained reasonably. The results show that under the PD caused by metal protrusion insulation fault without organic solid insulated materials, CO2, SO2F2, and SOF2 were the mainly decomposed components in the specific range of trace O2. Although no obvious influences of the trace O2 on the concentrations of CO2 and SOF2 as well as the ratio c(CO2)/c(SO2F2+SOF2), it is notable that the trace O2 is negatively and positively related to the concentration of SO2F2 and the ratio c(SOF2)/c(SO2F2), respectively. The exponential regression model can minimize the effect of trace O2 on the fault diagnostic result when using SF6 decomposed components. [ABSTRACT FROM AUTHOR]

To obtain the inner correlation feature between SF6 decomposition characteristics caused by the partial discharge (PD) of the free metal particle insulation fault and charge magnitude, a series of experiments are conducted on the designed experimental system. Three methods, namely, gas chromatograph, chromatography‐mass spectrometry and Fourier infrared spectroscopy, are used to quantitatively measure the decomposed components. Their content relation under different PD magnitudes is obtained and determined as SOF2 > SiF4 > SOF4 > SO2F2 > SO2 > S2F10 > CO2 > CF4, where the content of highly toxic S2F10 greatly exceeds its safe threshold. The study also discusses the correlation feature between each component of the free metal particle insulation fault and charge magnitude, which is found only when the charge magnitude reaches the point where it promotes the obvious formation of the components. Each component formation is found positively related to PD quantity. Based on a stability analysis of the produced components, five components are proposed to represent PD strength and the diagnosis table to recognise the severity of the metal particle insulation fault. This study attempts to lay a solid foundation for the conditional assessment of SF6 insulated equipment. [ABSTRACT FROM AUTHOR]

This paper aims to explore the decomposition characteristics of SF6 under thermal fault, which can further improve the method of using SF6 decomposed components to diagnose inner insulation status of SF6 insulated equipment. Hence, the thermal fault simulation system of SF6 electrical equipment is designed and serials of experiments are conducted. It initially gets SF6 thermal decomposition characteristic for temperature below 400°C. Then it analyzes decomposed component species and their generation regularity, determines the main characteristic component of SF6 thermal decomposition and chooses the key component to represent fault severity. The result shows that: SF6 begins to decompose obviously at 300°C and the main decomposition components contain CO2, SO2F2, SOF2, SOF4, SO2 and H2S; the improvement of fault temperature will promote the decomposition of SF6, but the formation regularity of each decomposed component is different; H2S is the special component only appears when thermal fault proceeds to some degree (above 360°C). Hence, decomposed components and their formation regularity can be used to diagnose the SF6 equipment thermal fault. H2S can be used as the key component to represent fault severity. [ABSTRACT FROM AUTHOR]

To obtain relationship between concentration of SF6 decomposed characteristic components (or their concentration ratio) during the formation process and partial discharge qualities and pulse repetition rate, this paper used needle-plate electrode to simulate outthrust insulation fault and conducted a serial of experiments. First, the SF6 decomposition characteristic under different PD strengths is obtained. Then this paper defines average discharge qualities per second as QSEC. It considers both apparent discharge qualities and discharge pulse repetition rate, and analyzes the relation feature between SF6 decomposition characteristic (both concentration of component and their effective formation rates RRMS) and QSEC. Besides, it proposes C(SO2F2)/C(SOF2) as the energy characteristic ratio (ER) to represent PD energy, and defines the effective energy characteristic ratio as (ERRMS). Moreover, it achieves the inner correlation feature between QSEC and all the characteristic component concentration, the RRMS of each characteristic component and ERRMS. The results show that: since number of C atoms from stainless steel surface and content of trace H2O and O2 in gas chamber were limited, both decomposed component concentration and component concentration ratio accords with the famous "Logistic Population Model" growth trend in ecology, which means they present ???S???-curve increase with QSEC. The proposed ER can effectively indicate the amount of PD energy and the defined ERRMS can objectively reveal the variance regularity of PD energy with QSEC. Hence, the correlation mathematic formula between ERRMS and QSEC is obtained and ERRMS can be used as the new characteristic parameter to represent PD energy. It establishes the foundation for the further fault diagnosis research. [ABSTRACT FROM PUBLISHER]

[Display omitted] • SF 6 and Ti 3 C 2 (OH) 2 surface have strong interaction during adsorption process. • Structure of SF 6 changes obviously with low-fluorine sulfide formed as a result of chemical adsorption. • Ti 3 C 2 T x terminated by hydroxyl is potential to be a catalyst for SF 6 decomposition. At present, searching for efficient methods to degrade sulfur hexafluoride (SF 6) is a worldwide hotspot. Due to the abundant active groups on the surface, MXene is regarded as an ideal catalyst support. In this paper, the potential active sites of Ti 3 C 2 T x (T = OH, F, O) for SF 6 degradation were studied using density functional theory (DFT) method. The results show the adsorption of SF 6 on Ti 3 C 2 (OH) 2 is significantly stronger than that on Ti 3 C 2 F 2 and Ti 3 C 2 O 2. Among typical adsorption sites on Ti 3 C 2 (OH) 2 , SF 6 exhibited the strongest interaction at OH-1 site. Complex electron orbital interactions occurred between SF 6 and Ti 3 C 2 (OH) 2. Adsorption energy reached −6.739 eV and about 1.414e transferred from Ti 3 C 2 (OH) 2 to SF 6. Structure of SF 6 changed obviously and chemical adsorption occurred in this process. However, on Ti 3 C 2 F 2 and Ti 3 C 2 O 2 , gas–solid interactions were weak and the structures had little change, which was mainly physical adsorption. Compared with common catalysts such as Ag, α ‑Al 2 O 3 and BaTiO 3 , Ti 3 C 2 (OH) 2 showed better catalytic activity for SF 6 degradation. By strong adsorption of the active site on the surface, the degradation products were separated from each other, which weakened SF 6 recombination and promoted the further degradation. The results provide theoretical support for MXene acting as a catalyst to efficiently degrade SF 6. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption of CS 2 and COF 2 on the surface of α-Al 2 O 3 (0 0 0 1) presents a state of energy release. • CS 2 is more easily adsorbed on the α-Al 2 O 3 (0 0 0 1) Surface by C atoms ;the surface of α-Al 2 O 3 (0 0 0 1) has a good adsorption effect on all three atom adsorption directions of COF 2 gas. • It is believed that new bonds may be generated during the adsorption process of the CS 2 and COF 2 gas molecules, and the structure after adsorption is more stable. As the typical carbon-containing decomposition components of SF 6 under partial discharge in high-voltage insulation devices, CS 2 and COF 2 , will not only corrode devices, but also pollute the environment. Remove these gases through SF 6 adsorbent is an effective approach to eliminate the above hazards. In this paper, the adsorption performance of CS 2 and COF 2 on α-Al 2 O 3 (0 0 0 1) surface was calculated by first-principle based density functional theory, including the adsorption enthalpy change, charge transfer and structural parameters, and five relatively stable adsorption structures were initially obtained through analysis. Results indicate that all adsorption processes are exothermic. To further understand the adsorption mechanism, the density of states, frontier molecular orbital and deformation charge density diagram were analyzed. Calculations show that both CS 2 and COF 2 has a fine adsorption effect on α-Al 2 O 3 (0 0 0 1) surface, besides, for CS 2 , it is easier to be adsorbed on α-Al 2 O 3 (0 0 0 1) surface through C atom while there is no significant difference in performance parameters of the adsorption configuration for COF 2. Furthermore, frontier molecular orbital analysis also confirmed that the adsorbed system is more stable. This work provide theoretical basis for the experiments of SF 6 adsorbents adsorbing typical carbon-containing decomposition components. [ABSTRACT FROM AUTHOR]