Oxygen diffusion in SrCe0.95Yb0.05O3??

A-site-cation deficiency in the SrCe0.9Yb0.1O3−δ perovskite: effects of charge-compensation mechanism on structure and proton conductivity

“…5 in Arrhenius form; the inset shows the resistivity at 400 C as a function of composition. The conductivity increases with increasing Sr deficiency up to x ¼ 0.04, ) rather than n-type electronic or oxide-ion conduction, which are associated with higher activation energies (e.g., 2.4 and 1.1 eV, respectively) 36,41 in SrCe(Yb)O 3Àd -based systems. The principal charge carriers of the Sr 1Àx Ce 0.9 Yb 0.1 O 3Àd series in wet reducing conditions in the examined temperature range are thus protons, in accordance with other reports of related SrCeO 3 -based phases in similar conditions.…”

Electrochemical Analysis of Catalytic and Oxygen Interfacial Transfer Effects on MnO2 Deposited on Gold Electrodes

“…As expected, the difference between ( E C1 ° – E A1 ° ) v →0 and ( E C1 ° – E A1 ° ) v →∞ was clearly lower than that obtained for MnO 2 –Au electrodes, 110 ± 10 mV, which permits to estimate Δ G M/MO ° = −32 ± 3 kJ mol –1 . This value is clearly lower than those estimated for the activation energy for cation vacancy diffusion of Mn­(II) in MnO (90–150 kJ mol –1 ) and oxygen ion diffusion in SrCe 0.95 Yb 0.05 O 3 (92–109 kJ mol –1 ), but this discrepancy can in principle be explained by the occurrence of the oxygen-transfer process through the highly hydrated double-layer region formed at the metal–MnO 2 interface boundary, as schematized in Figure .…”