The Influence of Sulfur Poisoning and YSZ Substrate Orientation on Electrochemical Properties of Nickel Pattern Anodes
In this study, pattern Ni anodes were investigated in H2/H2O atmosphere by means of electrochemical impedance spectroscopy (EIS). A sample pretreatment method was established to obtain stable values of the polarization resistance (RP) and interface capacitance (C) – i.e. avoiding degradation with time – to allow comparison of different microelectrodes. The effect of different YSZ substrate orientations on Rpand C is statistically evaluated and the correlation between the two properties is discussed.
Based on this knowledge the influence of H2S on Rp and C was investigated. The poisoning influence of sulfur on RP as well as the regeneration behavior was found to be qualitatively consistent with cermet electrodes described in the literature. Interestingly, also the electrode capacitance was affected by H2S: it decreased under sulfur poisoning conditions and regenerated partially after removal. Combined with dependencies of Rp and C on temperature, bias voltage and geometry these findings allow valuable insights into the electrochemical properties of Ni electrodes and their degradation.