|Title||Chemical equilibria involved in the oxygen-releasing step of manganese ferrite water-splitting thermochemical cycle|
|Publication Type||Articolo su Rivista peer-reviewed|
|Year of Publication||2008|
|Authors||Seralessandri, L., Bellusci M., Alvani C., La Barbera A., Padella F., and Varsano F.|
|Journal||Journal of Solid State Chemistry|
|Keywords||Chemical equilibriums, Energy sustainability, Ferrites, Hydrogen production, Manganese, Manganese ferrite, Manganese ferrites, Na de-intercalation, Nonmetals, Oxygen, Rietveld analysis, Sodium, Thermochemical water-splitting cycle, Water splitting cycles, Water-splitting, XRD|
Sodium ferrimanganite carbonatation reaction was investigated at different temperatures/carbon dioxide partial pressures to evaluate the feasibility of the thermochemical water-splitting cycle based on the MnFe2O4/Na2CO3/Na(Mn1/3Fe2/3)O2 system. After thermal treatments in selected experimental conditions, the obtained powder samples were investigated by using the X-ray diffraction (XRD) technique and Rietveld analysis. Two different lamellar Na1-xMn1/3Fe2/3O2-δ phases were observed together with the expected MnFe2O4/Na2CO3 mixture. Different equilibrium regions among sodium-depleted lamellar phases, manganese ferrite and sodium carbonate were found as a function of the different reaction conditions. A hypothesis concerning the regeneration mechanism of the initial compounds is proposed. Chemical equilibrium between stoichiometric and sub-stoichiometric forms of sodium ferrimanganite and sodium carbonate formation/dissociation appears to be essential factors governing the oxygen-releasing step of the manganese ferrite thermochemical cycle. © 2008 Elsevier Inc. All rights reserved.
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