The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System
Equilibrium phase formations below 600 K in the parts Ag<sub>2</sub>Te–FeTe<sub>2</sub>–F<sub>1.12</sub>Te–Ag<sub>2</sub>Te and Ag<sub>8</sub>GeTe<sub>6</sub>–GeTe–FeTe<sub>2</sub>–AgFeTe<sub>2</sub>–Ag&l...
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| Online Access: | https://www.mdpi.com/1996-1073/14/5/1314 |
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| author | Mykola Moroz Fiseha Tesfaye Pavlo Demchenko Myroslava Prokhorenko Nataliya Yarema Daniel Lindberg Oleksandr Reshetnyak Leena Hupa |
| author_facet | Mykola Moroz Fiseha Tesfaye Pavlo Demchenko Myroslava Prokhorenko Nataliya Yarema Daniel Lindberg Oleksandr Reshetnyak Leena Hupa |
| author_sort | Mykola Moroz |
| collection | DOAJ |
| description | Equilibrium phase formations below 600 K in the parts Ag<sub>2</sub>Te–FeTe<sub>2</sub>–F<sub>1.12</sub>Te–Ag<sub>2</sub>Te and Ag<sub>8</sub>GeTe<sub>6</sub>–GeTe–FeTe<sub>2</sub>–AgFeTe<sub>2</sub>–Ag<sub>8</sub>GeTe<sub>6</sub> of the Fe–Ag–Ge–Te system were established by the electromotive force (EMF) method. The positions of 3- and 4-phase regions relative to the composition of silver were applied to express the potential reactions involving the AgFeTe<sub>2</sub>, Ag<sub>2</sub>FeTe<sub>2</sub>, and Ag<sub>2</sub>FeGeTe<sub>4</sub> compounds. The equilibrium synthesis of the set of phases was performed inside positive electrodes (PE) of the electrochemical cells: (−)Graphite ‖LE‖ Fast Ag<sup>+</sup> conducting solid-electrolyte ‖R[Ag<sup>+</sup>]‖PE‖ Graphite(+), where LE is the left (negative) electrode, and R[Ag<sup>+</sup>] is the buffer region for the diffusion of Ag<sup>+</sup> ions into the PE. From the observed results, thermodynamic quantities of AgFeTe<sub>2</sub>, Ag<sub>2</sub>FeTe<sub>2</sub>, and Ag<sub>2</sub>FeGeTe<sub>4</sub> were experimentally determined for the first time. The reliability of the division of the Ag<sub>2</sub>Te–FeTe<sub>2</sub>–F<sub>1.12</sub>Te–Ag<sub>2</sub>Te and Ag<sub>8</sub>GeTe<sub>6</sub>–GeTe–FeTe<sub>2</sub>–AgFeTe<sub>2</sub>–Ag<sub>8</sub>GeTe<sub>6</sub> phase regions was confirmed by the calculated thermodynamic quantities of AgFeTe<sub>2</sub>, Ag<sub>2</sub>FeTe<sub>2</sub>, and Ag<sub>2</sub>FeGeTe<sub>4</sub> in equilibrium with phases in the adjacent phase regions. Particularly, the calculated Gibbs energies of Ag<sub>2</sub>FeGeTe<sub>4</sub> in two different adjacent 4-phase regions are consistent, which also indicates that it has stoichiometric composition. |
| first_indexed | 2024-03-09T06:12:54Z |
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| issn | 1996-1073 |
| language | English |
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| spelling | doaj.art-a89d6f346eb74ad5b9ea5297f6f5b24d2023-12-03T11:56:32ZengMDPI AGEnergies1996-10732021-02-01145131410.3390/en14051314The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te SystemMykola Moroz0Fiseha Tesfaye1Pavlo Demchenko2Myroslava Prokhorenko3Nataliya Yarema4Daniel Lindberg5Oleksandr Reshetnyak6Leena Hupa7Department of Chemistry and Physics, National University of Water and Environmental Engineering, 33028 Rivne, UkraineJohan Gadolin Process Chemistry Centre, Åbo Akademi University, 20500 Turku, FinlandDepartment of Inorganic Chemistry, Ivan Franko National University of Lviv, 79005 Lviv, UkraineDepartment of Cartography and Geospatial Modeling, Lviv Polytechnic National University, 79013 Lviv, UkraineDepartment of Cartography and Geospatial Modeling, Lviv Polytechnic National University, 79013 Lviv, UkraineDepartment of Chemical and Metallurgical Engineering, Aalto University, Kemistintie 1, 02150 Espoo, FinlandDepartment of Physical and Colloid Chemistry, Ivan Franko National University of Lviv, 79005 Lviv, UkraineJohan Gadolin Process Chemistry Centre, Åbo Akademi University, 20500 Turku, FinlandEquilibrium phase formations below 600 K in the parts Ag<sub>2</sub>Te–FeTe<sub>2</sub>–F<sub>1.12</sub>Te–Ag<sub>2</sub>Te and Ag<sub>8</sub>GeTe<sub>6</sub>–GeTe–FeTe<sub>2</sub>–AgFeTe<sub>2</sub>–Ag<sub>8</sub>GeTe<sub>6</sub> of the Fe–Ag–Ge–Te system were established by the electromotive force (EMF) method. The positions of 3- and 4-phase regions relative to the composition of silver were applied to express the potential reactions involving the AgFeTe<sub>2</sub>, Ag<sub>2</sub>FeTe<sub>2</sub>, and Ag<sub>2</sub>FeGeTe<sub>4</sub> compounds. The equilibrium synthesis of the set of phases was performed inside positive electrodes (PE) of the electrochemical cells: (−)Graphite ‖LE‖ Fast Ag<sup>+</sup> conducting solid-electrolyte ‖R[Ag<sup>+</sup>]‖PE‖ Graphite(+), where LE is the left (negative) electrode, and R[Ag<sup>+</sup>] is the buffer region for the diffusion of Ag<sup>+</sup> ions into the PE. From the observed results, thermodynamic quantities of AgFeTe<sub>2</sub>, Ag<sub>2</sub>FeTe<sub>2</sub>, and Ag<sub>2</sub>FeGeTe<sub>4</sub> were experimentally determined for the first time. The reliability of the division of the Ag<sub>2</sub>Te–FeTe<sub>2</sub>–F<sub>1.12</sub>Te–Ag<sub>2</sub>Te and Ag<sub>8</sub>GeTe<sub>6</sub>–GeTe–FeTe<sub>2</sub>–AgFeTe<sub>2</sub>–Ag<sub>8</sub>GeTe<sub>6</sub> phase regions was confirmed by the calculated thermodynamic quantities of AgFeTe<sub>2</sub>, Ag<sub>2</sub>FeTe<sub>2</sub>, and Ag<sub>2</sub>FeGeTe<sub>4</sub> in equilibrium with phases in the adjacent phase regions. Particularly, the calculated Gibbs energies of Ag<sub>2</sub>FeGeTe<sub>4</sub> in two different adjacent 4-phase regions are consistent, which also indicates that it has stoichiometric composition.https://www.mdpi.com/1996-1073/14/5/1314silver-based compoundsthermoelectric materialsphase equilibriathermodynamic propertiesGibbs energyEMF method |
| spellingShingle | Mykola Moroz Fiseha Tesfaye Pavlo Demchenko Myroslava Prokhorenko Nataliya Yarema Daniel Lindberg Oleksandr Reshetnyak Leena Hupa The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System Energies silver-based compounds thermoelectric materials phase equilibria thermodynamic properties Gibbs energy EMF method |
| title | The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System |
| title_full | The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System |
| title_fullStr | The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System |
| title_full_unstemmed | The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System |
| title_short | The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System |
| title_sort | equilibrium phase formation and thermodynamic properties of functional tellurides in the ag fe ge te system |
| topic | silver-based compounds thermoelectric materials phase equilibria thermodynamic properties Gibbs energy EMF method |
| url | https://www.mdpi.com/1996-1073/14/5/1314 |
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