Thermodynamic properties of misfit cobaltite [Bi2-xCa2O4] [CoO2](1.7)

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F17%3A43913372" target="_blank" >RIV/60461373:22310/17:43913372 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/60461373:22340/17:43913372

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0040603117302320" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0040603117302320</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.tca.2017.09.011" target="_blank" >10.1016/j.tca.2017.09.011</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Thermodynamic properties of misfit cobaltite [Bi2-xCa2O4] [CoO2](1.7)

Popis výsledku v původním jazyce

We synthetized a misfit structure cobaltite [Bi2-xCa2O4] [CoO2](1.7) and studied its thermal behavior by simultaneous thermal analysis (STA), low temperature heat capacity measurement in physical property measurement system (PPMS), differential scanning calorimetry (DSC) to measure heat capacity and drop calorimetry to obtain the relative enthalpy increments. The oxygen non-stoichiometry determined by thermogravimetry (STA data combined with weight loss measurement of the material reduced in hydrogen atmosphere) was analyzed in terms of point defect model resulting in two independent reactions, oxygen release and cobalt disproportionation, described by the respective enthalpy and entropy changes. The applied model satisfactorily describes two regimes of oxygen release/incorporation associated with the respective Co valency changes Co4+/Co3+ and Co3+/Co2+. The temperature dependence of the molar heat capacity above room temperature was derived by simultaneous least squares method from DSC and enthalpy data considering the contribution due to oxygen release and deviation from ideal stoichiometry. The low temperature heat capacity was analyzed in terms of a combined Debye Einstein model.

Název v anglickém jazyce

Thermodynamic properties of misfit cobaltite [Bi2-xCa2O4] [CoO2](1.7)

Popis výsledku anglicky

We synthetized a misfit structure cobaltite [Bi2-xCa2O4] [CoO2](1.7) and studied its thermal behavior by simultaneous thermal analysis (STA), low temperature heat capacity measurement in physical property measurement system (PPMS), differential scanning calorimetry (DSC) to measure heat capacity and drop calorimetry to obtain the relative enthalpy increments. The oxygen non-stoichiometry determined by thermogravimetry (STA data combined with weight loss measurement of the material reduced in hydrogen atmosphere) was analyzed in terms of point defect model resulting in two independent reactions, oxygen release and cobalt disproportionation, described by the respective enthalpy and entropy changes. The applied model satisfactorily describes two regimes of oxygen release/incorporation associated with the respective Co valency changes Co4+/Co3+ and Co3+/Co2+. The temperature dependence of the molar heat capacity above room temperature was derived by simultaneous least squares method from DSC and enthalpy data considering the contribution due to oxygen release and deviation from ideal stoichiometry. The low temperature heat capacity was analyzed in terms of a combined Debye Einstein model.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

Projekt

<a href="/cs/project/GA17-13161S" target="_blank" >GA17-13161S: Vliv nestechiometrie a nanostrukturování na materiálové vlastnosti oxidů kovů</a><br>

Návaznosti

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Thermochimica Acta

ISSN

0040-6031

e-ISSN

—

Svazek periodika

656

Číslo periodika v rámci svazku

OCT 10 2017

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

6

Strana od-do

129-134

Kód UT WoS článku

000414816900016

EID výsledku v databázi Scopus

2-s2.0-85029534437