Oxygen Surface Exchange Kinetics of Pr2(Ni,Co)O4+δ Thin-FilmModel Electrodes

Dense thin-film microelectrodes of the first-order Ruddlesden-Popper phases Pr2NiO4+δ (PNO) and Pr2Ni0.9Co0.1O4+δ (PNCO)were prepared by pulsed laser deposition and photolithographic patterning on yttria-stabilized zirconia (YSZ) substrates. The thinfilmswere characterized by X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductivelycoupled plasma optical emission spectroscopy, energy dispersive X-ray spectroscopy and electron energy loss spectroscopy. Investigationof the phase stability of PNO and its reactivity with YSZ was performed by X-ray diffraction analyses after high-temperaturetreatment in air. Resistive and capacitive contributions of the individual processes occurring at the microelectrodes were determinedby means of electrochemical impedance spectroscopy at various temperatures (550 ≤ T/°C ≤ 850) and oxygen partial pressures (1 ×10−3 ≤ pO2/bar ≤ 1). Oxygen surface exchange coefficients kq and kchem were calculated from the surface resistances and chemicalcapacitances of the thin-film electrodes. Comparing kq-values of PNO and PNCO shows that substitution of Ni with 10% of Coincreases the oxygen surface exchange rates, especially at lower oxygen partial pressures.© The Author(s) 2019. Published by ECS. This is an open access article distributed under the terms of the Creative CommonsAttribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in anymedium, provided the original work is properly cited. [DOI: 10.1149/2.0521914jes]