Electrochemical determination of activity of Na2O in Na2Ti6O13-TiO2 two phase system between 803–1000 K. (20th December 2017)

• Record Type: Journal Article
• Authors: Mudenda, Steven; Kale, Girish M.
• Is Part Of: Electrochimica acta. Volume 258(2017)
• Page Start: 1059
• Page End: 1063
• Publication Date: 2017-12-20
• Subjects: NT6-TiO2 -- Na2Ti6O13 + TiO2 -- EMF method -- Thermodynamics -- Thermodynamic stability -- NT6 -- NASICON -- Sodium beta alumina -- Sodium oxide activity; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.11.158
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Sodium oxide ( Na 2 O ) activity in NT6-TiO2 was measured using the EMF method with test electrode Pt, Na 2 Ti 6 O 13 +TiO2 (NT6-TiO2 ). NASICON ( Na 2 Zr 2 Si 2 PO 12 ) was used as the solid electrolyte in conjunction with a biphasic mixture of alpha alumina ( α -Al2 O3 ) and sodium beta alumina ( Na 2 O . x Al2 O3 ( 8.5 ≤ x < 11 ) ) as the reference electrode and measurements taken over the temperature range of 803 ≤ T ≤ 1000 K. Internal consistency of the cell was ensured by approaching the equilibration target temperature from both sides, during cooling and heating. EMF measurements showed linear dependency with temperature in the temperature range under study. The activity of Na 2 O in NT6- TiO 2 in the temperature range under study was determined. This was found to be log a Na 2 O ( N T 6 − TiO 2 ) = 1.20 − 13211 T . This data is important in the determination of theoretical EMF for the calibration electrochemical sensors employing NT6- TiO 2 electrode. Furthermore, it was found that, a Na 2 O ( N T 6 − TiO 2 ) > a Na 2 O ( N A S I C O N ) indicating chemical stability when in contact with NASICON at higher temperatures.