Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Marcin Gajek"

Comparative studies of the electrochemical behaviour of Me|Ba0.95Ca0.05Ce0.9Y0.1O3, Me|Ce0.8Gd0.2O1.9, and Me|Zr0.84Y0.16O1.9 systems caused by long-term cathode polarisation, where Me = Ag, Au quasi-point electrodes DOI:10.15199/28.2017.2.1

  Electrochemical measurements were performed with applied potential of -0.05 to -0.7 V at 700°C. An increase in absolute current was observed in chronoamperometric curves during long-term negative polarisation from -0.3 to -0.7 V for an Ag quasi-point electrode in Ag|E, E = Ba0.95Ca0.05Ce0.9Y0.1O3; Ce0.8Gd0.2O1.9, or Zr0.84Y0.16O1.9 systems. Decreases in ohmic resistance Rs and polarisation resistance Rp for Ag|Ba0.95Ca0.05Ce0.9Y0.1O3, Ce0.8Gd0.2O1.9, and Zr0.84Y0.16O1.9 systems were determined by means of electrochemical impedance spectroscopy in analogous conditions. Confocal or scanning electron microscopy observation confirmed the migration of silver particles onto ceramic electrolytes under long-term negative polarisation. A silver deposit was found near the site of direct contact of the Ag electrode with the surface of the Ba0.95Ca0.05Ce0.9Y0.1O3 electrolyte. An expansion of the reaction zone in the Ag|Ba0.95Ca0.05Ce0.9Y0.1O3 system is the main reason for the increase in absolute current values. A similar electrochemical response was found in the case of zirconia or ceria-based solid electrolytes with Ag quasi-point electrodes. The effect of the chemical composition and physicochemical properties of ceramic electrolytes and applied negative potential on electrochemical response in Au|Ba0.95Ca0.05Ce0.9Y0.1O3, Au|Ce0.8Gd0.2O1.9, and Au|Zr0.84Y0.16O1.9 systems was recorded. In the case of Au|Ba0.95Ca0.05Ce0.9Y0.1O3 system, during negative polarisation with an applied potential in the range from -0.05 to -0.3 V, a small increase in absolute current values was observed on the chronoamperometric curves. In the case of Au|Ba0.95Ca0.05Ce0.9Y0.1O3 system, decreases in ohmic resistance Rs and polarisation resistance Rp were noticed vs applied potential. Key words: ceramic proton ion conductor, BaCe0.9Y0.1O3, point-electrode, intermediate temperature solid oxide electrolyte, oxygen reduction process.1. INTRODUCTION The [...]

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