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Author | Cui, Z. | ||||
Title | Experimental and theoretical study on SF6 degradation by packed-bed DBD plasma | Type | Doctoral thesis | ||
Year | 2021 | Publication | Abbreviated Journal | ||
Volume | Issue | Pages | |||
Keywords | Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | Sulfur hexafluoride (SF6), as a man-made gas, is widely used in power industry, semiconductor industry and metal-processing industry. However, SF6 is a greenhouse gas and its global warming potential is 23500 times that of CO2. Besides, SF6 is very stable, with a lifetime in the atmosphere for more than one thousand years. Under natural conditions, only the ultraviolet light can make it slowly decomposed. Thus, the emission of SF6 has a great threat to the environment. In recent years, with the development of our national economy, the use of SF6 increased dramatically. And 90% of the SF6 emissions come from the power industry. In the meantime, the emission of SF6 exists a ‘hysteresis effect’, as many of the SF6-gas insulation equipment will retire in next decades, the emission of SF6 may increase sharply, and this may put great pressure on the environment. Therefore, it’s necessary to make efforts in controlling and treating the SF6 emission. Among the SF6 abatement technologies, the non-thermal plasma(NTP) represented by the dielectric barrier discharge(DBD) can effectively degrade SF6 and is suitable for large-scale industry applications. However, its energy efficiency still gets room for improvement and this kind of method has a defect that it’s hard to regulate the degradation by-products. Therefore, this paper proposed the combination of the packed bed reactor and the DBD technology to form a packed DBD discharge system for SF6 degradation, so that to further improve the energy efficiency and regulate the selectivity of by-products. By experiment and simulation research, the following innovations have been achieved: (1) Based on the packed bed DBD platform, the power parameter and gas-phase parameters of SF6 degradation were studied. It was found that the discharge process was significantly enhanced with the addition of packing particles, and the discharge energy efficiency was improved. The increase of input voltage can obviously increase the degradation rate, but reduces the energy efficiency. The increase of SF6 initial concentration and gas flow rate can improve the energy efficiency, but reduce the degradation rate. Therefore, both degradation rate and energy efficiency should be considered in deciding basic experimental conditions. (2) Active gases, such as O2, H2O and NH3, could effectively promote the degradation rate of SF6, and changed the product selectivity. In our packed bed DBD system, O2 and H2O have the optimal concentration conditions, which are 2% and 1%, respectively. The addition of O2 can promote the generation of S-O-F products, and inhibit the selectivity of SO2, while the addition of H2O had the opposite effects. In addition, the synergistic degradation of NH3 and SF6 will produce solid products, such as NH3HF, NH4HF2 and elemental S. For gaseous products, the increase of NH3 will lead to the generation of SO2 in the final degradation products and inhibit the generation of S-O-F products. (3) Different kinds of packing materials have great impacts on the degradation system in the discharge parameters, degradation rate and energy efficiency, as well as the products distribution. In the experiment, we compared the degradation results in three systems: glass beads packing, γ-Al2O3 packing and no-packing system. The packing of glass beads effectively improved the discharge voltage amplitude and discharge power, while had a limited effect on the equivalent capacitance of the dielectric. Besides, γ-Al2O3 packing had little effect on voltage amplitude, but obviously increased the equivalent capacitance of the dielectric. Furthermore, the degradation rate and energy efficiency in γ-Al2O3 system was higher than that of glass bead system. For products selectivity, γ-Al2O3 system was more desirable, where S-O-F type of product selectivity was suppressed and the SO2 selectivity increased significantly. By contrast, the glass beads system hardly affected the product selectivity. This results are presumably due to the relatively high dielectric constant of γ-Al2O3 particles and γ-Al2O3 itself may act as a reactant or a catalyst participating in the degradation reactions. (4) The size and status of the packing particles also have significant effects on the degradation process. The systems packed with 1, 2 and 4mm γ-Al2O3 particles for SF6 degradation were compared, and the 2mm system had the best performance, which may because the 2mm system had a good balance between the active contact area and the gas residence time. In addition, the packing pellets suffered from a hydration process slightly reduced the discharge parameters in the γ-Al2O3 packing system and significantly reduced the degradation rate was, which may because the H2O molecules pre-occupied the active sites on the γ-Al2O3 surface and reduced the discharge process. (5) Based on density functional theory (DFT), the degradation process of SF6 in the packed bed DBD system was studied at atomic scale. It was found that the SF6 can occur a physical adsorption at AlⅢ active sites on γ-Al2O3 surface. The activation barrier for the first degradation step of SF6 on γ-Al2O3 surface is much lower than in gas phase, which proved that the SF6 molecule is activated on the γ-Al2O3 surface. In addition, the plasma may affect the γ-Al2O3 surface to generate excess electrons or external electric fields. This two effects can change the adsorbed SF6 molecules from physical adsorption to chemisorption, together with an obvious stretching of S-F bonds, indicating that the plasma surface effects prmote the activation and decomposition of SF6 molecules. Furthermore, the stepwise degradation process of SF6 on γ-Al2O3 surface were investigated. The influence of radicals produced by plasma on the degradation process was analyzed. It was found that via Eley–Rideal (ER) reactions, high-energy radicals could effectively reduce the activation barriers and promote the surface reactions. Finally, the degradation mechanism of SF6 molecules in the packed bed plasma system was summarized, which may provide a theoretical basis for the study of harmless degradation of SF6. Keywords: SF6; Packed Bed DBD; Discharge Parameters; Products Analysis; Degradation Mechanism | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | Publication Date | |||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | ISBN | Additional Links | UA library record | ||
Impact Factor ![]() |
Times cited | Open Access | |||
Notes | Approved | Most recent IF: NA | |||
Call Number | UA @ admin @ c:irua:180819 | Serial | 7946 | ||
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Author | Cui, Z.; Jafarzadeh, A.; Hao, Y.; Liu, L.; Li, L.; Zheng, Y. | ||||
Title | Prediction of the decomposition tendency of C5F10O on discharged metal surfaces | Type | A1 Journal article | ||
Year | 2023 | Publication | IEEE transactions on dielectrics and electrical insulation | Abbreviated Journal | |
Volume | 30 | Issue | 3 | Pages | 1365-1367 |
Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | In this letter, a dipole sheet method is proposed to theoretically study the adsorption and decomposition of C5F10O over-discharged Cu (111) and Al (111) surfaces. A synergistic effect of external electric fields and surface excess charges shows up for jointly promoting the adsorption of C5F10O, accompanied by the enhancement of C-F bond elongation and charge transfer process. The decomposition of C5F10O is facilitated in the discharged region and the initial decomposition is found most likely to occur via the cleavage of the C-F single bond. The results indicate that the decomposition of C5F10O over the metal electrode surfaces is much accelerated when discharge faults occur and free F atoms could be generated from C5F10O before its carbon chain breakage. These findings help to elucidate the underlying decomposition tendency of C5F10O in discharged systems and provide a practical method for evaluating and designing new insulation gases. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001000675800054 | Publication Date | 2023-03-29 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 1070-9878 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor ![]() |
3.1 | Times cited | Open Access | ||
Notes | Approved | Most recent IF: 3.1; 2023 IF: 2.115 | |||
Call Number | UA @ admin @ c:irua:197319 | Serial | 9076 | ||
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Author | Cui, Z.; Zhou, C.; Jafarzadeh, A.; Zhang, X.; Hao, Y.; Li, L.; Bogaerts, A. | ||||
Title | SF₆ degradation in γ-Al₂O₃ packed DBD system : effects of hydration, reactive gases and plasma-induced surface charges | Type | A1 Journal article | ||
Year | 2023 | Publication | Plasma chemistry and plasma processing | Abbreviated Journal | |
Volume | 43 | Issue | Pages | 635-656 | |
Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | Packed-bed DBD (PB-DBD) plasmas hold promise for effective degradation of greenhouse gases like SF6. In this work, we conducted a combined experimental and theoretical study to investigate the effect of the packing surface structure and the plasma surface discharge on the SF6 degradation in a gamma-Al2O3 packing DBD system. Experimental results show that both the hydration effect of the surface (upon moisture) and the presence of excessive reactive gases in the plasma can significantly reduce the SF6 degradation, but they hardly change the discharge behavior. DFT results show that the pre-adsorption of species such as H, OH, H2O and O-2 can occupy the active sites (Al-III site) which negatively impacts the SF6 adsorption. H2O molecules pre-adsorbed at neighboring sites can promote the activation of SF6 molecules and lower the reaction barrier for the S-F bond-breaking process. Surface-induced charges and local external electric fields caused by the plasma can both improve the SF6 adsorption and enhance the elongation of the S-F bonds. Our results indicate that both the surface structure of the packing material and the plasma surface discharge are crucial for SF6 degradation performance, and the packing beads should be kept dry during the degradation. This work helps to understand the underlying mechanisms of SF6 degradation in a PB-DBD system. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000966639200001 | Publication Date | 2023-04-10 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0272-4324 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor ![]() |
3.6 | Times cited | Open Access | OpenAccess | |
Notes | Approved | Most recent IF: 3.6; 2023 IF: 2.355 | |||
Call Number | UA @ admin @ c:irua:196033 | Serial | 8516 | ||
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Author | Meng, S.; Wu, L.; Liu, M.; Cui, Z.; Chen, Q.; Li, S.; Yan, J.; Wang, L.; Wang, X.; Qian, J.; Guo, H.; Niu, J.; Bogaerts, A.; Yi, Y. | ||||
Title | Plasma‐driven<scp>CO2</scp>hydrogenation to<scp>CH3OH</scp>over<scp>Fe2O3</scp>/<scp>γ‐Al2O3</scp>catalyst | Type | A1 Journal Article | ||
Year | 2023 | Publication | AIChE Journal | Abbreviated Journal | AIChE Journal |
Volume | 69 | Issue | 10 | Pages | e18154 |
Keywords | A1 Journal Article; chemisorbed oxygen, CO2 hydrogenation, iron-based catalyst, methanol production, plasma catalysis; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ; | ||||
Abstract | We report a plasma‐assisted CO<sub>2</sub>hydrogenation to CH<sub>3</sub>OH over Fe<sub>2</sub>O<sub>3</sub>/γ‐Al<sub>2</sub>O<sub>3</sub>catalysts, achieving 12% CO<sub>2</sub>conversion and 58% CH<sub>3</sub>OH selectivity at a temperature of nearly 80°C atm pressure. We investigated the effect of various supports and loadings of the Fe‐based catalysts, as well as optimized reaction conditions. We characterized catalysts by X‐ray powder diffraction (XRD), hydrogen temperature programmed reduction (H<sub>2</sub>‐TPR), CO<sub>2</sub>and CO temperature programmed desorption (CO<sub>2</sub>/CO‐TPD), high‐resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), x‐ray photoelectron spectroscopy (XPS), Mössbauer, and Fourier transform infrared<bold>(</bold>FTIR). The XPS results show that the enhanced CO<sub>2</sub>conversion and CH<sub>3</sub>OH selectivity are attributed to the chemisorbed oxygen species on Fe<sub>2</sub>O<sub>3</sub>/γ‐Al<sub>2</sub>O<sub>3</sub>. Furthermore, the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) and TPD results illustrate that the catalysts with stronger CO<sub>2</sub>adsorption capacity exhibit a higher reaction performance.<italic>In situ</italic>DRIFTS gain insight into the specific reaction pathways in the CO<sub>2</sub>/H<sub>2</sub>plasma. This study reveals the role of chemisorbed oxygen species as a key intermediate, and inspires to design highly efficient catalysts and expand the catalytic systems for CO<sub>2</sub>hydrogenation to CH<sub>3</sub>OH. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 001022420000001 | Publication Date | 2023-07-07 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0001-1541 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor ![]() |
3.7 | Times cited | Open Access | Not_Open_Access | |
Notes | Fundamental Research Funds for the Central Universities, DUT18JC42 ; National Natural Science Foundation of China, 21908016 21978032 ; | Approved | Most recent IF: 3.7; 2023 IF: 2.836 | ||
Call Number | PLASMANT @ plasmant @c:irua:197829 | Serial | 8959 | ||
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Author | Cui, Z.; Zhou, C.; Jafarzadeh, A.; Meng, S.; Yi, Y.; Wang, Y.; Zhang, X.; Hao, Y.; Li, L.; Bogaerts, A. | ||||
Title | SF₆ catalytic degradation in a γ-Al₂O₃ packed bed plasma system : a combined experimental and theoretical study | Type | A1 Journal article | ||
Year | 2022 | Publication | High voltage | Abbreviated Journal | |
Volume | Issue | Pages | 1-11 | ||
Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | Effective abatement of the greenhouse gas sulphur hexafluoride (SF6) waste is of great importance for the environment protection. This work investigates the size effect and the surface properties of gamma-Al2O3 pellets on SF6 degradation in a packed bed dielectric barrier discharge (PB-DBD) system. Experimental results show that decreasing the packing size improves the filamentary discharges and promotes the ignition and the maintenance of plasma, enhancing the degradation performance at low input powers. However, too small packing pellets decrease the gas residence time and reduce the degradation efficiency, especially for the input power beyond 80 W. Besides, lowering the packing size promotes the generation of SO2, while reduces the yields of S-O-F products, corresponding to a better degradation. After the discharge, the pellet surface becomes smoother with the appearance of S and F elements. Density functional theory calculations show that SF6 is likely to be adsorbed at the Al-III site over the gamma-Al2O3(110) surface, and it is much more easily to decompose than in the gas phase. The fluorine gaseous products can decompose and stably adsorb on the pellet surface to change the surface element composition. This work provides a better understanding of SF6 degradation in a PB-DBD system. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000827312700001 | Publication Date | 2022-07-20 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2397-7264 | ISBN | Additional Links | UA library record; WoS full record | |
Impact Factor ![]() |
4.4 | Times cited | Open Access | OpenAccess | |
Notes | Approved | Most recent IF: 4.4 | |||
Call Number | UA @ admin @ c:irua:189603 | Serial | 7208 | ||
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Author | Cui, Z.; Hao, Y.; Jafarzadeh, A.; Li, S.; Bogaerts, A.; Li, L. | ||||
Title | The adsorption and decomposition of SF6 over defective and hydroxylated MgO surfaces: A DFT study | Type | A1 Journal article | ||
Year | 2023 | Publication | Surfaces and interfaces | Abbreviated Journal | |
Volume | 36 | Issue | Pages | 102602 | |
Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | Plasma degradation is one of the most effective methods for the abatement of greenhouse gas sulfur hexafluoride (SF6). To evaluate the potential of MgO as a catalyst in plasma degradation, we investigate the catalytic properties of MgO on SF6 adsorption and activation by density functional theory (DFT) where the O-defective and hydroxylated surfaces are considered as two typical plasma-generated surfaces. Our results show that perfect MgO (001) and (111) surfaces cannot interact with SF6 and only physical adsorption happens. In case of Odefective MgO surfaces, the O vacancy is the most stable adsorption site. SF6 undergoes a decomposition to SF5 and F over the O-defective MgO (001) surface and undergoes an elongation of the bottom S-F bond over the Odefective (111) surface. Besides, SF6 shows a physically adsorption at the stepsite of the MgO (001) surface, accompanied by small changes in its bond angle and length. Furthermore, SF6 is found to be physically and chemically adsorbed over 0.5 and 1.0 ML (monolayer) H-covered O-terminated MgO (111) surfaces, respectively. The SF6 molecule undergoes a self-decomposition on the 1.0 ML hydroxylated surface via a surface bonding process. This study shows that defective and hydroxylated MgO surfaces have the surface capacities for SF6 activation, which shows that MgO has potential as packing material in SF6 waste treatment in packed-bed plasmas. |
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000916285000001 | Publication Date | 2022-12-24 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2468-0230 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor ![]() |
6.2 | Times cited | Open Access | OpenAccess | |
Notes | National Natural Science Foundation of China, 52207155 ; Fonds Wetenschappelijk Onderzoek; Vlaams Supercomputer Centrum; Vlaamse regering; | Approved | Most recent IF: 6.2; 2023 IF: NA | ||
Call Number | PLASMANT @ plasmant @c:irua:194364 | Serial | 7244 | ||
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Author | Yi, Y.; Li, S.; Cui, Z.; Hao, Y.; Zhang, Y.; Wang, L.; Liu, P.; Tu, X.; Xu, X.; Guo, H.; Bogaerts, A. | ||||
Title | Selective oxidation of CH4 to CH3OH through plasma catalysis: Insights from catalyst characterization and chemical kinetics modelling | Type | A1 Journal Article;Methane conversion | ||
Year | 2021 | Publication | Applied Catalysis B-Environmental | Abbreviated Journal | Appl Catal B-Environ |
Volume | 296 | Issue | Pages | 120384 | |
Keywords | A1 Journal Article;Methane conversion; Plasma catalysis; Selective oxidation; Methanol synthesis; Plasma chemistry; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ; | ||||
Abstract | The selective oxidation of methane to methanol (SOMTM) by molecular oxygen is a holy grail in catalytic chemistry and remains a challenge in chemical industry. We perform SOMTM in a CH4/O2 plasma, at low temperature and atmospheric pressure, promoted by Ni-based catalysts, reaching 81 % liquid oxygenates selectivity and 50 % CH3OH selectivity, with an excellent catalytic stability. Chemical kinetics modelling shows that CH3OH in the plasma is mainly produced through radical reactions, i.e., CH4 + O(1D) → CH3O + H, followed by CH3O + H + M→ CH3OH + M and CH3O + HCO → CH3OH + CO. The catalyst characterization shows that the improved production of CH3OH is attributed to abundant chemisorbed oxygen species, originating from highly dispersed NiO phase with strong oxide support interaction with γ-Al2O3, which are capable of promoting CH3OH formation through E-R reactions and activating H2O molecules to facilitate CH3OH desorption. | ||||
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Corporate Author | Thesis | ||||
Publisher | Place of Publication | Editor | |||
Language | Wos | 000706860000003 | Publication Date | 2021-05-21 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0926-3373 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor ![]() |
9.446 | Times cited | Open Access | OpenAccess | |
Notes | National Natural Science Foundation of China; PetroChina Innovation Foundation; We acknowledge financial support from the PetroChina Innovation Foundation [grant ID: 2018D-5007-0501], the Young Star Project of Dalian Science and Technology Bureau [grant ID: 2019RQ042], the National Natural Science Foundation of China [grant ID: 21503032] and the TOP research project of the Research Fund of the University of Antwerp [grant ID: 32249]. | Approved | Most recent IF: 9.446 | ||
Call Number | PLASMANT @ plasmant @c:irua:178816 | Serial | 6793 | ||
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Author | Cui, Z.; Meng, S.; Yi, Y.; Jafarzadeh, A.; Li, S.; Neyts, E.C.; Hao, Y.; Li, L.; Zhang, X.; Wang, X.; Bogaerts, A. | ||||
Title | Plasma-catalytic methanol synthesis from CO₂ hydrogenation over a supported Cu cluster catalyst : insights into the reaction mechanism | Type | A1 Journal article | ||
Year | 2022 | Publication | Acs Catalysis | Abbreviated Journal | Acs Catal |
Volume | 12 | Issue | 2 | Pages | 1326-1337 |
Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
Abstract | Plasma-catalytic CO, hydrogenation for methanol production is gaining increasing interest, but our understanding of its reaction mechanism remains primitive. We present a combined experimental/computational study on plasma-catalytic CO, hydrogenation to CH3OH over a size-selected Cu/gamma-Al2O3 catalyst. Our experiments demonstrate a synergistic effect between the Cu/gamma-Al2O3 catalyst and the CO2/H-2 plasma, achieving a CO2 conversion of 10% at 4 wt % Cu loading and a CH3OH selectivity near 50% further rising to 65% with H2O addition (for a H2O/CO2 ratio of 1). Furthermore, the energy consumption for CH3OH production was more than 20 times lower than with plasma only. We carried out density functional theory calculations over a Cu-13/gamma-Al2O3 model, which reveal that the interfacial sites of the Cu-13 cluster and gamma-Al2O3 support show a bifunctional effect: they not only activate the CO2 molecules but also strongly adsorb key intermediates to promote their hydrogenation further. Reactive plasma species can regulate the catalyst surface reactions via the Eley-Rideal (E-R) mechanism, which accelerates the hydrogenation process and promotes the generation of the key intermediates. H2O can promote the CH3OH desorption by competitive adsorption over the Cu-13/gamma-Al2O3 surface. This study provides new insights into CO2 hydrogenation through plasma catalysis, and it provides inspiration for the conversion of some other small molecules (CH4, N-2, CO, etc.) by plasma catalysis using supported-metal clusters. | ||||
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Publisher | Place of Publication | Editor | |||
Language | Wos | 000742735600001 | Publication Date | 2022-01-07 | |
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 2155-5435 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
Impact Factor ![]() |
12.9 | Times cited | Open Access | OpenAccess | |
Notes | Approved | Most recent IF: 12.9 | |||
Call Number | UA @ admin @ c:irua:186416 | Serial | 7192 | ||
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