1
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Tada S, Ogura Y, Sato M, Yoshida A, Honma T, Nishijima M, Joutsuka T, Kikuchi R. Difference in reaction mechanism between ZnZrO x and InZrO x for CO 2 hydrogenation. Phys Chem Chem Phys 2024; 26:14037-14045. [PMID: 38686433 DOI: 10.1039/d4cp00635f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Oxide solid-solution catalysts, such as Zn-doped ZrO2 (ZnZrOx) and In-doped ZrO2 (InZrOx), exhibit distinctive catalytic capabilities for CH3OH synthesis via CO2 hydrogenation. We investigated the active site structures of these catalysts and their associated reaction mechanisms using both experimental and computational approaches. Electron microscopy and X-ray absorption spectroscopy reveal that the primary active sites are isolated cations, such as Zn2+ and In3+, dissolved in tetragonal ZrO2. Notably, for Zn2+, decomposition of the methoxy group, which is an essential intermediate in CH4 synthesis, is partially suppressed because of the relatively high stability of the methoxy group. Conversely, the methyl group strongly adsorbs on In3+, facilitating the conversion of the methoxy species into methyl groups. The decomposition of CH3OH is also suggested to contribute to CH4 synthesis. These results highlight the generation of CH4 as a byproduct of the InZrOx catalyst. Understanding the active site structure and elucidating the reaction mechanism at the atomic level are anticipated to contribute significantly to the future development of oxide solid-solution catalysts.
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Affiliation(s)
- Shohei Tada
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan.
| | - Yurika Ogura
- Department of Materials Science and Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan
| | - Motohiro Sato
- Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 030-8651, Japan
| | - Akihiro Yoshida
- Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 030-8651, Japan
- Institute of Regional Innovation, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 030-8651, Japan
| | - Tetsuo Honma
- Japan Synchrotron Radiation Research Institute, Sayo-gun, Hyogo 679-5198, Japan
| | - Masahiko Nishijima
- Flexible 3D System Integration Laboratory, Osaka University, 8-1 Mihogaoka Ibaraki-Shi, Osaka 567-0047, Japan
| | - Tatsuya Joutsuka
- Department of Materials Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
| | - Ryuji Kikuchi
- Division of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan.
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Wu JW, Xie YP, Yao MY, Guan SH, Zhao Y, Pan RJ, Wu L, Liu ZP. Unraveling different influences of the fraction of the tetragonal phase in oxide films on the corrosion resistance of Zr alloys from the phase transition mechanism. Phys Chem Chem Phys 2023; 25:8934-8947. [PMID: 36916876 DOI: 10.1039/d2cp05345d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The mechanism of Sn and Nb influence on the fraction of tetragonal ZrO2 in oxide films on Zr alloys and their influence mechanism on corrosion resistance of Zr alloys, despite decades of research, are ambiguous due to the lack of kinetic knowledge of phase evolution of ZrO2 with doping. Using stochastic surface walking and density functional theory calculations, we investigate the influence of Nb and Sn on the stability of tetragonal (t) and monoclinic (m) ZrO2, and t-m phase transition in oxide films. We found that though Nb and Sn result in similar apparent variation trends in the t-phase fraction in oxide films, their influences on t-m phase transition differ significantly, which is the underlying origin of different influences of the t-phase fraction in oxide films on the corrosion resistance of Zr alloys with Sn and Nb alloying. These results clarify an important aspect of the relationship between the microstructure and corrosion resistance of Zr alloys.
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Affiliation(s)
- Jiang-Wei Wu
- Institute of Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China.
| | - Yao-Ping Xie
- Institute of Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China.
| | - Mei-Yi Yao
- Institute of Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China.
| | - Shu-Hui Guan
- The Education Ministry Key Laboratory of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234, China
| | - Yi Zhao
- Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, 610213, China
| | - Rong-Jian Pan
- Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, 610213, China
| | - Lu Wu
- Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, 610213, China
| | - Zhi-Pan Liu
- Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
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3
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Stability of Hydroxo/Oxo/Fluoro Zirconates vs. Hafniates—A DFT Study. INORGANICS 2022. [DOI: 10.3390/inorganics10120259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We performed density functional theory (DFT) calculations on binary and ternary oxo/fluoro crystals of the geochemical twin pair zirconium and hafnium to evaluate and compare their stabilities. This is the first DFT study on bulk ZrF4 or HfF4, as well as on a hypothetical ZrOF2 or HfOF2 bulk crystal. For α-MO2, β-MF4 and MOF2, we have found significantly higher cohesive energies for the respective hafnium species. This suggests a considerable gap in affinity toward fluorine and oxygen between the twin pair in the solid state. In agreement with experimental findings, this gap is slightly more pronounced for fluorine. This study is also the first to evaluate the theoretical, endothermic mono-hydroxylation of the respective fluorides or oxyfluorides to model the difference in affinity toward fluoride versus hydroxide. For these, we could also find a slight energetic preference for the hafnium compound.
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Influence of Th, Zr, and Ti Dopants on Solution Property of Xe in Uranium Dioxide with Defects: A DFT + U Study. METALS 2022. [DOI: 10.3390/met12050879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To ensure the safety and efficient operation of nuclear reactors, it is imperative to understand the effects of various dopants (Ti, Th, and Zr) on the solubility of the fission product Xe in UO2. In this study, Hubbard corrected density functional theory (DFT + U) and occupation matrix control were used to investigate the bulk and defect properties of UO2. The results show that the UO2-Ti system is more favorable for Xe dissolution in vacancies, whereas the UO2-Th system has little effect on the dissolution of Xe atoms. Th, Zr, and Ti inhibit the aggregation of Xe clusters, and Ti is the least favorable for the nucleation and growth of Xe clusters.
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Delarmelina M, Catlow CRA. Cation-doping strategies for tuning of zirconia acid-base properties. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211423. [PMID: 35223057 PMCID: PMC8864357 DOI: 10.1098/rsos.211423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/14/2022] [Indexed: 05/03/2023]
Abstract
The role of Y-, Ca- and Ce-doping of cubic zirconia (c-ZrO2) (111) surface on its acidity, basicity and the interplay between surface acid-base pairs is investigated by computational methods. The most stable surface structures for this investigation were initially determined based on previous studies of Y-doped c-ZrO2 (111) and by a detailed exploration of the most stable configuration for Ca-doped c-ZrO2 (111) and Ce-doped c-ZrO2 (111). Next, surface mapping by basic probe molecules (NH3 and pyridine) revealed a general reduction of the acidity of the surface sites, although a few exceptions were observed for zirconium ions at next nearest neighbour (NNN) positions to the oxygen vacancy and at the nearest neighbour (NN) position to the dopants. Adsorption of CO2 over basic sites revealed a cooperative interplay between acid-base groups. In this case, the overall effect observed was the decrease of the calculated adsorption energies when compared with the pristine surface. Moreover, spontaneous formation of η 3-CO2 systems from initial η 2-CO2 configurations indicates a decrease in the required energy for forming oxygen vacancies in the doped ZrO2 systems at NNN positions or further away from the existing vacancy site.
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Affiliation(s)
- Maicon Delarmelina
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
- UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
| | - C. Richard A. Catlow
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
- UK Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
- Department of Chemistry, University College London, 20 Gordon Street, London WC1 HOAJ, UK
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Delarmelina M, Deshmukh G, Goguet A, Catlow CRA, Manyar H. Role of Sulfation of Zirconia Catalysts in Vapor Phase Ketonization of Acetic Acid. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:27578-27595. [PMID: 34970379 PMCID: PMC8713292 DOI: 10.1021/acs.jpcc.1c06920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/17/2021] [Indexed: 06/14/2023]
Abstract
The effect of the sulfation of zirconia catalysts on their structure, acidity/basicity, and catalytic activity/selectivity toward the ketonization of organic acids is investigated by a combined experimental and computational method. Here, we show that, upon sulfation, zirconia catalysts exhibit a significant increase in their Brønsted and Lewis acid strength, whereas their Lewis basicity is significantly reduced. Such changes in the interplay between acid-base sites result in an improvement of the selectivity toward the ketonization process, although the measured conversion rates show a significant drop. We report a detailed DFT investigation of the putative surface species on sulfated zirconia, including the possible formation of dimeric pyrosulfate (S2O7 2-) species. Our results show that the formation of such a dimeric system is an endothermic process, with energy barriers ranging between 60.0 and 70.0 kcal mol-1, and which is likely to occur only at high SO4 2- coverages (4 S/nm2), high temperatures, and dehydrating conditions. Conversely, the formation of monomeric species is expected at lower SO4 2- coverages, mild temperatures, and in the presence of water, which are the usual conditions experienced during the chemical upgrading of biofuels.
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Affiliation(s)
- Maicon Delarmelina
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
| | - Gunjan Deshmukh
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- School
of Chemistry and Chemical Engineering, Queen’s
University Belfast, David-Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom
| | - Alexandre Goguet
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- School
of Chemistry and Chemical Engineering, Queen’s
University Belfast, David-Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom
| | - C. Richard A. Catlow
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- Department
of Chemistry, University College London, 20 Gordon St., London WC1 HOAJ, United
Kingdom
| | - Haresh Manyar
- UK
Catalysis Hub, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, United Kingdom
- School
of Chemistry and Chemical Engineering, Queen’s
University Belfast, David-Keir Building, Stranmillis Road, Belfast BT9 5AG, United Kingdom
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Khattab ESR, Abd El Rehim SS, Hassan WMI, El-Shazly TS. Band Structure Engineering and Optical Properties of Pristine and Doped Monoclinic Zirconia ( m-ZrO 2): Density Functional Theory Theoretical Prospective. ACS OMEGA 2021; 6:30061-30068. [PMID: 34778677 PMCID: PMC8582270 DOI: 10.1021/acsomega.1c04756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/14/2021] [Indexed: 06/13/2023]
Abstract
Recently, monoclinic ZrO2 has received great technological importance because of its remarkable dielectric properties, high chemical stability, and high melting point. Herein, we introduce first-principles calculations using the Hubbard approach (DFT + U) to study the effects of doping with Nb and W on the electronic and optical properties of pristine ZrO2. The introduction of dopant atoms into the pristine crystal structure led to the displacement of the bandgap edges and reallocation of the Fermi level. The valence band maximum (VBM) shifted upward, resulting in band gap tightening from 5.79 to 0.89 for ZrO2: Nb and to 1.33 eV for ZrO2: W. The optical absorption of doped crystals extended into the visible and near-infrared regions. Partial density of states (PDOS) calculations showed valence band dependency on the O 2p orbital energy, with the conduction band predominantly composed of Nb 4d and W 5d. For pristine ZrO2, the results obtained for the imaginary and real parts of the dielectric function, the refractive index, and the reflectivity show good agreement with the available experimental and theoretical results. For ZrO2:W, we checked the dopant location effect, and the obtained results showed no significant effect on the calculated values of the band gap with a maximum difference of 0.17 eV. Significant band gap tightening and optical properties of our systems indicate that these systems could be promising candidates for photoelectrochemical energy conversion (PEC) applications.
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Affiliation(s)
- El-Sayed R. Khattab
- Department
of Chemistry, Faculty of Science, Ain-Shams
University, Cairo 11566, Egypt
| | - Sayed S. Abd El Rehim
- Department
of Chemistry, Faculty of Science, Ain-Shams
University, Cairo 11566, Egypt
| | - Walid M. I. Hassan
- Department
of Chemistry, Faculty of Science, Cairo
University, Giza 12613, Egypt
| | - Tamer S. El-Shazly
- Department
of Chemistry, Faculty of Science, Ain-Shams
University, Cairo 11566, Egypt
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8
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Zhang R, Chutia A, Sokol AA, Chadwick D, Catlow CRA. A computational investigation of the adsorption of small copper clusters on the CeO 2(110) surface. Phys Chem Chem Phys 2021; 23:19329-19342. [PMID: 34524332 DOI: 10.1039/d1cp02973h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a detailed density functional theory (DFT) study of the geometrical and electronic properties, and the growth mechanism of a Cun (n = 1-4) cluster on a stoichiometric, and especially on a defective CeO2(110) surface with one surface oxygen vacancy, without using pre-assumed gas-phase Cun cluster shapes. This gives new and valuable theoretical insight into experimental work regarding debatable active sites of promising CuOx/CeO2-nanorod catalysts in many reactions. We demonstrate that CeO2(110) is highly reducible upon Cun adsorption, with electron transfer from Cun clusters, and that a Cun cluster grows along the long bridge sites until Cu3, so that each Cu atom can interact strongly with surface oxygen ions at these sites, forming stable structures on both stoichiometric and defective CeO2(110) surface. Cu-Cu interactions are, however, limited, since Cu atoms are distant from each other, inhibiting the formation of Cu-Cu bonds. This monolayer then begins to grow into a bilayer as seen in the Cu3 to Cu4 transition, with long-bridge site Cu as anchoring sites. Our calculations on Cu4 adsorption reveal a Cu bilayer rich in Cu+ species at the Cu-O interface.
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Affiliation(s)
- Rui Zhang
- Dept of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | | | - Alexey A Sokol
- Dept of Chemistry, University College London, 20 Gordon St., London WC1H 0AJ, UK
| | - David Chadwick
- Dept of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - C Richard A Catlow
- Dept of Chemistry, University College London, 20 Gordon St., London WC1H 0AJ, UK.,School of Chemistry, Cardiff University, Park Place, Cardiff CF10 1AT, UK
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Cornil D, Rivolta N, Mercier V, Wiame H, Beljonne D, Cornil J. Enhanced Adhesion Energy at Oxide/Ag Interfaces for Low-Emissivity Glasses: Theoretical Insight into Doping and Vacancy Effects. ACS APPLIED MATERIALS & INTERFACES 2020; 12:40838-40849. [PMID: 32804476 DOI: 10.1021/acsami.0c07579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low-emissivity glasses rely on multistacked architectures with a thin silver layer sandwiched between oxide layers. The mechanical stability of the silver/oxide interfaces is a critical parameter that must be maximized. Here, we demonstrate by means of quantum-chemical calculations that a low work of adhesion at interfaces can be significantly increased via doping and by introducing vacancies in the oxide layer. For the sake of illustration, we focus on the ZrO2(111)/Ag(111) interface exhibiting a poor adhesion in the pristine state and quantify the impact of introducing n-type dopants or p-type dopants in ZrO2 and vacancies in oxygen atoms (nVO; with n = 1, 2, 4, 8, 10, 16), zirconium atoms (mVZr; with m = 1, 2, 4, 8), or both (nVO + mVZr; with m/n = 1:2, 1:4, 2:2, 2:4). In the case of doping, interfacial electron transfer promotes an increase in the work of adhesion, from initially 0.16 to ∼0.8 J m-2 (n-type) and ∼2.0 J m-2 (p-type) at 10% doping. A similar increase in the work of adhesion is obtained by introducing vacancies, e.g., VO [VZr] in the oxide layer yields a work of adhesion of ∼1.5-2.0 J m-2 at 10% vacancies. An increase is also observed when mixing VO and VZr vacancies in a nonstoichiometric ratio (nVO + mVZr; with 2n ≠ m), while a stoichiometric ratio of VO and VZr has no impact on the interfacial properties.
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Affiliation(s)
- David Cornil
- Laboratory for Chemistry of Novel Materials, University of Mons (UMONS), Place du Parc 20, 7000 Mons, Belgium
| | - Nicolas Rivolta
- AGC Glass Europe Technovation Centre, rue Louis Blériot 12, 6041 Gosselies, Belgium
| | - Virginie Mercier
- AGC Glass Europe Technovation Centre, rue Louis Blériot 12, 6041 Gosselies, Belgium
| | - Hughes Wiame
- AGC Glass Europe Technovation Centre, rue Louis Blériot 12, 6041 Gosselies, Belgium
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons (UMONS), Place du Parc 20, 7000 Mons, Belgium
| | - Jérôme Cornil
- Laboratory for Chemistry of Novel Materials, University of Mons (UMONS), Place du Parc 20, 7000 Mons, Belgium
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T. AM, Kuriakose N, Mondal K, Ghosh P. CO2 capture, activation and dissociation on the Ti2C surface and Ti2C MXene: the role of surface structure. Phys Chem Chem Phys 2020; 22:14599-14612. [DOI: 10.1039/d0cp01700k] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Barrier-less CO2 activation on Ti2C(100) and MXene with preferential adsorption on the (100) surface and a lower dissociation barrier on MXene.
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Affiliation(s)
- Aswathi Mohan T.
- Department of Chemistry
- Indian Institute of Science Education and Research
- Pune
- India
| | - Nishamol Kuriakose
- Department of Physics
- Indian Institute of Science Education and Research
- Pune
- India
| | - Krishnakanta Mondal
- Department of Physics
- Indian Institute of Science Education and Research
- Pune
- India
| | - Prasenjit Ghosh
- Department of Physics
- Indian Institute of Science Education and Research
- Pune
- India
- Centre for Energy Sciences
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