The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System

Moroz, Mykola; Tesfaye, Fiseha; Demchenko, P.; Прохоренко, М. В.; Yarema, Nataliya; Lindberg, Daniel; Reshetnyak, Оleksandr; Hupa, Leena

doi:10.3390/en14051314

Cited by 9 publications

(5 citation statements)

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“…The process of forming the thermodynamically stable set of phases from the metastable phase mixture of finely dispersed substances was conducted in the R(Ag + ) region. The Ag + ions served as the small nucleation centers of formation of the stable phases [25][26][27]. After completion of the synthesis process, the GCs (A) were used for E vs. T measurements.…”

Section: Methodsmentioning

confidence: 99%

“…The reason for this may be the intermediate compound AgIn 3 Te 5 , which is predicted for the equilibrium T-x space of the Ag 2 Te-In 2 Te 3 cross-section at moderate temperatures [22,23]. The lack of information about the AgIn 3 Te 5 compound in [18][19][20][21] is probably related to the metastable state (for kinetic reasons) of the mixture of the AgInTe 2 and AgIn 5 Te 8 compounds below 680 K. The possibility of overcoming kinetic obstacles to the formation of a thermodynamically stable set of chalcogenide and chalcohalide phases from a metastable phase mixture of compounds in the galvanic cells (GCs) with the participation of the Ag + ions was reported in [24][25][26][27]. Nevertheless, there is a lack of information on the thermal stabilities and thermodynamic properties of the ternary compounds in the Ag-In-Te system.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Thermodynamic Characterization of the Chalcopyrite-Based Compounds in the Ag–In–Te System for a Potential Thermoelectric Application

et al. 2022

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The equilibrium concentration space of the Ag–In–Te system in the part AgInTe2–Te–In2Te3 was studied through the modified solid-state electromotive force (EMF) method by dividing In2Te3–In2Te5–Ag3In97Te147 (I), In2Te5–Te–Ag3In97Te147 (II), Ag3In97Te147–Te–AgIn5Te8 (III), AgIn5Te8–Te–AgIn3Te5 (IV), and AgIn3Te5–Te–AgInTe2 (V), into separate phase regions at T ≤ 500 K. The formation of a thermodynamically stable combination of the binary and ternary phases in the (I)–(V) phase regions from a metastable phase mixture of substances was carried out at T ≤ 500 K in the R(Ag+) part of the positive electrode (PE) of the galvanic cells (GCs) of the structure: (−) C |∙| Ag |∙| SE |∙| R(Ag+) |∙| PE |∙| C (+), where C is the graphite (inert electrode), SE is the solid-state electrolyte (Ag3GeS3Br glass), and Ag is the left (negative) electrode. The Ag+ ions in the R(Ag+) region functioned as small nucleation centers for the formation of the stable phases. The spatial position of the (I)–(V) phase regions in the concentration space of the Ag–In–Te system relative to the position of silver was used to express the overall potential-forming reactions with the participation of the substances Ag, Te, In2Te5, Ag3In97Te147, AgIn5Te8, AgIn3Te5, and AgInTe2. The subsequent EMF measurements were carried out by applying the same GCs. The temperature dependences of the EMF of GCs with PE of the (I)–(V) phase regions were here used to determine, for the first time, the values of standard thermodynamic functions of the binary and ternary compounds. The determined values of the Gibbs energies of the formation of compounds are equal: GIn2Te5○=(182.7±1.9) kJ·mol−1, GAgInTe2○=(115.0±3.1) kJ·mol−1, GAgIn3Te5○=(301.5±6.5) kJ·mol−1, GAgIn5Te8○=(487.6±11.3) kJ·mol−1, and GAg3In97Te147○=(8594±189) kJ·mol−1 The correctness of the division of the equilibrium phase space of the Ag–In–Te system in the part AgInTe2–Te–In2Te3 involving the AgInTe2, AgIn3Te5, AgIn5Te8, and Ag3In97Te147 compounds was confirmed by the agreement of the calculated and literature-based thermodynamic data for In2Te5 compound. Compositions of pairs of the ternary compounds for their subsequent practical application were proposed.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental Thermodynamic Characterization of the Chalcopyrite-Based Compounds in the Ag–In–Te System for a Potential Thermoelectric Application

et al. 2022

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“…Визначені в експериментах за Т<500 К фізико-хімічні властивості сполук та твердих розчинів на їхній основі з метастабільною кристалічною структурою можуть неконтрольовано змінюватись з часом під дією зовнішніх чинників, тому їх практичне використання є проблематичним. Не виключається варіант кінетичних перешкод вакуумного синтезу багатоелементних сполук із простих речовин, простих речовин і бінарних сполук за Т≤500 К. В наших дослідженнях виявлено можливість долати кінетичні перешкоди перебудові метастабільних аргентумовмісних сплавів, використовуючи йони аргентуму Ag + як малі центри зародження рівноважних фаз [1,2].…”

Section: вступunclassified

THERMODYNAMIC PROPERTIES OF THE AgGaGe3Se8 COMPOUND AT Т≤500 K DETERMINED BY THE EMF METHOD

Moroz¹,

Demchenko²,

Прохоренко³

et al. 2022

Proc. Shevchenko Sci. Soc. Chem. Sci.

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The division of the concentration space of the Ag–Ga–Ge–Se system in the GeSe–Se–Ga2Se3–AgGaGe3Se8–GeSe section was carried out by the EMF method. The concentration space of the Ag–Ga–Ge–Se system contains the four-phase regions GeSe2–Se–Ga2Se3–AgGaGe3Se8 (I) and GeSe–GeSe2–Ga2Se3–AgGaGe3Se8 (II). The spatial positions of these phase regions vs the point of silver were used to express equations of the overall cell reactions of synthesis of the AgGaGe3Se8 compound: 2Ag + 6GeSe2 + Ga2Se3 + Se = 2AgGaGe3Se8 and 2Ag + 7GeSe2 + Ga2Se3 = GeSe + 2AgGaGe3Se8. Reactions were performed in the positive electrodes of the following electrochemical cells (ECCs): (−) С | Ag | SЕ | R(Ag+) | PЕ | С (+), where C is graphite, Ag is the left (negative) electrode, SE is the purely Ag+ ion conducting solid electrolyte (Ag3GeS3Br-glass), PE is the right (positive) electrode, and R(Ag+) is the region of PE that contact with SE. Shifted from the left electrode to the R(Ag+) region for thermodynamic reasons Ag+ ions acted as the small nucleation centers for reconstruction of the metastable mixtures of compounds in the thermodynamically stable mixture of phases. Linear dependences of EMF vs temperature of ECCs were used to calculate the standard thermodynamic properties of the AgGaGe3Se8 equilibrium in the regions (I) and (II): ∆_f G_((I))^○= –(575,0 ± 8,9) kJ·mol −1, ∆_f H_((I))^○= –(574,7 ± 12,0) kJ·mol−1, S_((I))^○ = (515,9 ± 14,1) J·(mol·K)−1 and ∆_f G_((II))^○ = –(588,4 ± 9,4) kJ·mol−1, ∆_f H_((II))^○ = –(590,6 ± 12,9) kJ·mol−1, S_((II))^○ = (507,8 ± 13,2) J·(mol·K)−1, respectively. The relative difference between the calculated values ∆_f G_((I))^○ and ∆_f G_((II))^○ within ~2.3% and the overlap of the uncertainty intervals characterize the four-phase sections (I) and (II) by the combination of compounds of the formula composition. Moreover, values of the partial thermodynamic functions of the potential-determining component (Ag) of the AgGaGe3Se8 compound were calculated.

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“…Taking this into account, we undertook a comprehensive study of phase equilibria and thermodynamic properties of the GeTe-Bi2Te3-Te system by the method of electromotive forces (EMF). Various modifications of this EMF method with liquid [30][31][32][33][34][35][36] and solid [36][37][38][39][40][41] electrolytes are successfully used to study chalcogenide systems.…”

Section: Introductionmentioning

confidence: 99%

Solid-phase equilibria in the GeBi2Te4-Bi2Te3-Te system and thermodynamic properties of compounds of the GeTe·mBi2Te3 homologous series

Alakbarova

Orujlu

Бабанлы³

et al. 2022

Phys. Chem. Solid St.

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The GeBi2Te4-Bi2Te3-Te system was investigated by XRD and EMF measurements of the reversible concentration cell of the type (-) GeTe (solid) │glycerol +KCl │ Ge-Bi-Тe (solid) (+) in the 300-450K temperature range. It was shown that, in the indicated temperature range, elementary tellurium forms tie lines with all telluride phases of the system. Equations for the temperature dependencies of EMF in all phase regions have been obtained from the data of EMF measurements, from which the partial thermodynamic functions of GeTe in alloys have been calculated. The partial molar functions of germanium in alloys were determined by combining obtained data with the thermodynamic functions of GeTe. Standard Gibbs free energy and enthalpy of formation, as well as the standard entropy of the GeBi2Te4, GeBi4Te7, GeBi6Te10 compounds and solid solutions based on Bi2Te3 have been calculated using these data, solid-phase equilibrium diagram of the GeBi2Te4-Bi2Te3-Te system, and corresponding thermodynamic functions of Bi2Te3.

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The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System

Cited by 9 publications

References 58 publications

Experimental Thermodynamic Characterization of the Chalcopyrite-Based Compounds in the Ag–In–Te System for a Potential Thermoelectric Application

Experimental Thermodynamic Characterization of the Chalcopyrite-Based Compounds in the Ag–In–Te System for a Potential Thermoelectric Application

THERMODYNAMIC PROPERTIES OF THE AgGaGe3Se8 COMPOUND AT Т≤500 K DETERMINED BY THE EMF METHOD

Solid-phase equilibria in the GeBi2Te4-Bi2Te3-Te system and thermodynamic properties of compounds of the GeTe·mBi2Te3 homologous series

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