Dense thin-film microelectrodes of the first-order Ruddlesden-Popper phases Pr2NiO4+delta (PNO) and Pr2Ni0.9Co0.1O4+delta (PNCO) were prepared by pulsed laser deposition and photolithographic patterning on yttria-stabilized zirconia (YSZ) substrates. The thinfilms were characterized by X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, energy dispersive X-ray spectroscopy and electron energy loss spectroscopy. Investigation of the phase stability of PNO and its reactivity with YSZ was performed by X-ray diffraction analyses after high-temperature treatment in air. Resistive and capacitive contributions of the individual processes occurring at the microelectrodes were determined by means of electrochemical impedance spectroscopy at various temperatures (550 <= T/degrees C <= 850) and oxygen partial pressures (1 x 10(-3) = pO(2)/bar <= 1). Oxygen surface exchange coefficients k(q) and k(chem) were calculated from the surface resistances and chemical capacitances of the thin-film electrodes. Comparing k(q)-values of PNO and PNCO shows that substitution of Ni with 10% of Co increases the oxygen surface exchange rates, especially at lower oxygen partial pressures. (C) The Author(s) 2019. Published by ECS.