TY - JOUR
T1 - Experimental determination of the Onsager coefficients of transport for Ce0.8Pr0.2O2−δ
AU - Chatzichristodoulou, Christodoulos
AU - Park, Woo-Seok
AU - Kim, Hong-Seok
AU - Hendriksen, Peter Vang
AU - Yoo, Han-Ill
PY - 2010
Y1 - 2010
N2 - For a mixed oxide-ion and electron conducting oxide, with oxygen vacancies and electrons (e′) or holes (h˙) as charge carriers, a flux of (Ji) can in principle be driven, not only directly by its own electrochemical potential gradient (∇ηi), but also indirectly by that of electrons (∇ηe), and vice versa for the flux of electrons (Je). It is common practice to assume that electrons and mobile ions migrate independently, despite the lack of experimental evidence in support of this. Here, all the Onsager coefficients, including the cross coefficients, have been measured for Ce0.8Pr0.2O2−δ within the aO2 range 10−21–1 at 800 °C, using local ionic and electronic probes in a four-probe configuration. The cross coefficients of transport were found to be negligible in comparison to the direct coefficients in the aO2 range 10−21–10−4, but of the same order of magnitude as the direct coefficients for high aO2 values (10−2–1). This is in contrast to the commonly used assumption that the two types of carriers migrate independently, i.e. that Lie = 0.
AB - For a mixed oxide-ion and electron conducting oxide, with oxygen vacancies and electrons (e′) or holes (h˙) as charge carriers, a flux of (Ji) can in principle be driven, not only directly by its own electrochemical potential gradient (∇ηi), but also indirectly by that of electrons (∇ηe), and vice versa for the flux of electrons (Je). It is common practice to assume that electrons and mobile ions migrate independently, despite the lack of experimental evidence in support of this. Here, all the Onsager coefficients, including the cross coefficients, have been measured for Ce0.8Pr0.2O2−δ within the aO2 range 10−21–1 at 800 °C, using local ionic and electronic probes in a four-probe configuration. The cross coefficients of transport were found to be negligible in comparison to the direct coefficients in the aO2 range 10−21–10−4, but of the same order of magnitude as the direct coefficients for high aO2 values (10−2–1). This is in contrast to the commonly used assumption that the two types of carriers migrate independently, i.e. that Lie = 0.
KW - Fuel Cells and Hydrogen
KW - Membranes
KW - Brændselsceller og brint
KW - Membraner
U2 - 10.1039/C000865F
DO - 10.1039/C000865F
M3 - Journal article
VL - 12
SP - 9637
EP - 9649
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 33
ER -