TY - JOUR
T1 - Effect of substitution of B-sites by Mn, Fe and Co in double perovskite-type Ba3CaNb2O9 on structure and electrical properties
AU - Kan, Wang Hay
AU - Roushanafshar, Milad
AU - Vincent, Adrien
AU - Fürstenhaupt, Tobias
AU - Parvez, Masood
AU - Luo, Jingli
AU - Thangadurai, Venkataraman
PY - 2013/12/7
Y1 - 2013/12/7
N2 - A novel family of metal oxides of chemical formula Ba2Ca (1-x-y)M(x+z)Nb(1-z+y)O6-δ (M = Mn, Fe and Co) was developed as mixed ion and electronic conductors (MIECs) for application in solid oxide fuel cells (SOFCs). Investigated samples were synthesized by a ceramic method at 1400 °C in air and characterized using powder X-ray diffraction (PXRD), selected area electron diffraction (SAED), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), dilatometry, chemical titration and electrochemical ac impedance spectroscopy (EIS). The Rietveld analysis of PXRD and SAED support the formation of ordered double perovskite-type structure with space group Fm3m and chemical stability in 5000 ppm H2S/H2 at 600 °C. Iodometric titration shows the valences of Mn and Co were 2+ and 3+, while Fe shows 3+ and 4+ states. SEM reveals that the porosity of the samples is highly affected by dopants. The thermal expansion coefficients (TEC) of the as-prepared samples are very comparable to the oxide conducting Y-doped ZrO2. Ba2Ca0.79Co0.5Nb 0.71O6-δ exhibits the total conductivity of 3.7 × 10-2 S cm-1 at 816 °C in air. The trend in the conductivity of Ba2Ca(1-x-y)M(x+z)Nb (1-z+y)O6-δ could be correlated to the reduction of the dopants and the subsequent loss of oxide ions at elevated temperatures.
AB - A novel family of metal oxides of chemical formula Ba2Ca (1-x-y)M(x+z)Nb(1-z+y)O6-δ (M = Mn, Fe and Co) was developed as mixed ion and electronic conductors (MIECs) for application in solid oxide fuel cells (SOFCs). Investigated samples were synthesized by a ceramic method at 1400 °C in air and characterized using powder X-ray diffraction (PXRD), selected area electron diffraction (SAED), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), dilatometry, chemical titration and electrochemical ac impedance spectroscopy (EIS). The Rietveld analysis of PXRD and SAED support the formation of ordered double perovskite-type structure with space group Fm3m and chemical stability in 5000 ppm H2S/H2 at 600 °C. Iodometric titration shows the valences of Mn and Co were 2+ and 3+, while Fe shows 3+ and 4+ states. SEM reveals that the porosity of the samples is highly affected by dopants. The thermal expansion coefficients (TEC) of the as-prepared samples are very comparable to the oxide conducting Y-doped ZrO2. Ba2Ca0.79Co0.5Nb 0.71O6-δ exhibits the total conductivity of 3.7 × 10-2 S cm-1 at 816 °C in air. The trend in the conductivity of Ba2Ca(1-x-y)M(x+z)Nb (1-z+y)O6-δ could be correlated to the reduction of the dopants and the subsequent loss of oxide ions at elevated temperatures.
U2 - 10.1039/c3ra44429e
DO - 10.1039/c3ra44429e
M3 - Article
AN - SCOPUS:84886864356
SN - 2046-2069
VL - 3
SP - 23824
EP - 23832
JO - RSC Advances
JF - RSC Advances
IS - 45
ER -