Ab-initio study of molybdenum carbide (Mo2C) as an adsorption-based filter

Hassan, Arif; Ilyas, Syed Zafar; Ahmed, Sarfraz; Niaz, Faiza; Jalil, Abdul; Khan, Qasim

doi:10.1016/j.physleta.2020.127119

Cited by 7 publications

(6 citation statements)

References 51 publications

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“…In order to eliminate the interference of air on each sample and make the experimental results more accurate, the response of the background gas to the three samples at different temperatures (RT-350 °C) has been tested first. 36 The unresponsive results indicate that the air will not interfere with the test results. In this work, a gas-sensitive test was conducted with the temperature gradient for SO 2 and SO 2 F 2 at 150 ppm.…”

Section: Resultsmentioning

confidence: 99%

“…Numerous studies have shown that the adsorption performance of gas sensors is greatly affected by temperature, − so it is necessary to analyze the operating temperature when exploring the adsorption characteristics of gas sensors. In order to eliminate the interference of air on each sample and make the experimental results more accurate, the response of the background gas to the three samples at different temperatures (RT-350 °C) has been tested first . The unresponsive results indicate that the air will not interfere with the test results.…”

Section: Resultsmentioning

confidence: 99%

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Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF₆ Decomposition Species

Wang,

Wu,

Zhang

et al. 2024

ACS Appl. Nano Mater.

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SF 6 equipment internal insulation faults generate trace amounts of characteristic gases, mainly SO 2 and SO 2 F 2 . Accurately tracing such small amounts of gas at a low temperature is rather necessary for SF 6 equipment status monitoring and fault diagnosis to ensure safe and stable operation of the power system. In this work, we present a gas sensor with ultrahigh sensitivity, excellent low-temperature performance, low detection limits, fast response, and superior recovery performance for detecting SO 2 and SO 2 F 2 , employing molybdenum carbide nanowires with an oxygen content of 13.60% (Mo 2 C-500) as the sensing material. Gassensing test results show that the sensing performance of Mo 2 C enhances with the increase of the oxygen content, and that Mo 2 C-500 shows the most outstanding sensing performance for SO 2 and SO 2 F 2 among all three oxygenated Mo 2 C (oxygen contents of 0, 5.80, and 13.60%). In addition, at the optimum operating temperatures of 250 °C (SO 2 ) and 150 °C (SO 2 F 2 ), the response value (response time) of Mo 2 C-500 is 2.75(24 s) and 3.61(26 s) toward 300 ppm of SO 2 and SO 2 F 2 , and the detection limits for SO 2 and SO 2 F 2 are 0.83 and 1.01 ppm, respectively. Moreover, the potential adsorption mechanism upon SO 2 and SO 2 F 2 by oxygenated Mo 2 C nanowires is further explored by density functional theory (DFT) calculations that the introduction of oxygen promotes the generation of more free electrons and the formation of a deeper electron depletion layer, giving rise to the enhanced sensing response to SO 2 and SO 2 F 2 . This study demonstrates that the Mo 2 C-500 gas sensor with excellent performance and low cost has superior application prospects in detecting SF 6 decomposition species, which serves as a basis for the development of nanogas sensors.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF₆ Decomposition Species

Wang,

Wu,

Zhang

et al. 2024

ACS Appl. Nano Mater.

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“…With the increase of w(Mo), the reduction peak of Mo 4+ species moved backward and the peak area increased, indicating that the interaction between MoO 2 and AC carrier was enhanced. 30 The desorption peak of AC centered at 855°C is attributed to the desorption of hydroxyl, lactone, and quinone carbonyl functional groups with high thermal stability. These oxygen-containing functional groups decompose after heating and escape as CO 2 .…”

Section: Resultsmentioning

confidence: 99%

“…‐C(ONO 2 ) can be further decomposed into NO 2 + CO or NO+CO 2 22,28,29 . NO 2 easily interacts with the surface of Mo 2 C and decomposes into one NO molecule and one O atom, and the formed O atom combines with Mo atom to form three MoO bonds 30 . The desorption peak of AC centered at 855°C is attributed to the desorption of hydroxyl, lactone, and quinone carbonyl functional groups with high thermal stability.…”

Section: Resultsmentioning

confidence: 99%

Synergy effects of Mo₂C and AC on the structure and catalytic performance of Mo₂C/AC for NO₂ to NO

Wang

et al. 2023

J of Chemical Tech & Biotech

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Background: Research on catalysts for the efficient conversion of NO 2 to NO is of great significance for the accurate determination of NO 2 concentration and the reduction of environmental pollution. The present work investigated the synergistic interaction between coconut shell activated carbon (AC) and Mo 2 C, along with the catalytic performance of NO 2 to NO. The aim of this study was to prepare a composite catalyst with activated carbon as the support to improve the conversion of NO 2 at low temperatures. The effect of Mo loading w(Mo) on the reaction performance of NO 2 to NO was studied by technical analysis, and the internal mechanism of Mo 2 C/AC for improving the reaction activity of the catalyst was revealed to provide a reference for the development of new efficient NO 2 converting agents.Results: Commercially available Mo 2 C, AC, and Mo 2 C/AC catalysts can convert NO 2 to NO under reaction test conditions. When the gas flow rate is 1.5 L/min and the temperature is 250°C, the NO 2 conversion rates of 5-Mo 2 C/AC, 10-Mo 2 C/AC, 15-Mo 2 C/AC, and 20-Mo 2 C/AC are 96.1%, 97.8%, 97.0%, and 93.2%, respectively. The NO 2 conversion rates of 10-Mo 2 C/AC is about 4 times that of Mo 2 C and 1.1 times that of AC at 250 °C. Conclusion:The Mo 2 C/AC catalyst is rich in micropores and provides a reaction vessel for the conversion of NO 2 to NO. AC with high specific surface area can not only change the dispersion and particle size of Mo 2 C species on the catalyst surface, but also adjust the NOx desorption performance of the catalyst. The synergism between the AC and Mo 2 C of Mo 2 C/AC provides more active sites for NO 2 to NO, improving the reaction performance of the catalyst.

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“…Yang et al [29] calculated the surface energy of α-Mo 2 C(023) plane and found that the Y doping can facilitate the electron escaping from the α-Mo 2 C(023) surface, resulting in stronger surface activities. The work by Hassan et al [30] revealed that various poisonous gas molecules can be chemisorbed on various locations of molybdenum carbide monolayer with high adsorption energies. Leitner et al [31] built an interface model between Fe and Mo 2 C with different planes and terminations, the results show that the elasticity of the Fe/Mo 2 C composite is dominated by the elastic properties of the two materials, while the bonding at the interface only has a minor impact.…”

Section: Introductionmentioning

confidence: 99%

Insight into Point Defects and Complex Defects in β-Mo2C and Carbide Evolution from First Principles

et al. 2022

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In this paper, first principles method was adopted to investigate the point defects, Vanadium-related defects and defect combinations (vacancy (V), substitutional (S) and/or interstitial (I)) in molybdenum β-Mo2C and explore the use of first principles calculation data in analysing the link between different carbides and the effects of doping elements. Supercell models with different defect types were established and optimized, and the formation energy data of defects was developed. The structure evolution during the optimization process is analysed in detail to establish the main characteristics of changes and the relevant electronic properties. The data for different types of intrinsic defects and combined defects complexes was developed and key results is analysed. The results show that carbon vacancy (VC) is stable but does not inevitably exist in pure β-Mo2C. Interstitial site II is a very unstable position for any type of atoms (Mo, V and C), and analysis of the structure evolution shows that the atom always moves to the interface area near the interstitial site I between two layers. In particular, a C atom can expand the lattice structure when it exists between the layer interfaces. One type of the defects studied, the substitution of Mo with V (designated as ‘SV-Mo’), is the most stable defect among all single point defects. The data for defect complexes shows that the combination of multiple SV-Mo defects in the super cell being more stable than the combination of other defects (e.g., ‘VMo+IC’, ‘SV-Mo+VC’). The data with increasing SV-Mo in (Mo, V)2C system is developed, and typical data (e.g., formation energy) for Mo-rich carbides and V carbides are correlated and the potential of the data in analysing transition of different carbides is highlighted. The relevance of using first principles calculation data in the studying of V-doping and the complex carbides (V- and Mo-rich carbides) evolution in different materials systems and future focus of continuous work is also discussed.

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Ab-initio study of molybdenum carbide (Mo2C) as an adsorption-based filter

Cited by 7 publications

References 51 publications

Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF₆ Decomposition Species

Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF₆ Decomposition Species

Synergy effects of Mo₂C and AC on the structure and catalytic performance of Mo₂C/AC for NO₂ to NO

Insight into Point Defects and Complex Defects in β-Mo2C and Carbide Evolution from First Principles

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Ab-initio study of molybdenum carbide (Mo2C) as an adsorption-based filter

Cited by 7 publications

References 51 publications

Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF6 Decomposition Species

Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF6 Decomposition Species

Synergy effects of Mo2C and AC on the structure and catalytic performance of Mo2C/AC for NO2 to NO

Insight into Point Defects and Complex Defects in β-Mo2C and Carbide Evolution from First Principles

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Product

Resources

About

Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF₆ Decomposition Species

Oxygenated Molybdenum Carbide Nanowires for Enhanced Sensing of Characteristic SF₆ Decomposition Species

Synergy effects of Mo₂C and AC on the structure and catalytic performance of Mo₂C/AC for NO₂ to NO