Influence of the Activation Catalyst on the Polarization Resistance of Electroless Cu Electrodes on BaCe0.1Zr0.8Y0.1O3-δ proton-Conducting Ceramics

Abstract

Copper (Cu) electrodes appear as potential methane dehydroaromatization (MDA) electrodes on BaCexZr0.9-xY0.1O3- δ (BCZY) proton-conducting ceramics [1]. When applied from paste, the electrodes suffer from poor adhesion, and therefore high polarization resistance. In this work, 1 micron thin Cu electrodes were deposited onto BaCe0.1Zr0.8Y0.1O3-d (BCZY18) specimens by electroless plating, using three different activation catalysts: Pd, Ru and Cu [2]. Impedance spectra were recorded on electrolyte based symmetric cells Cu/BCZY/Cu in the temperature range 750-600°C, in dry and moist reducing atmospheres. The area specific resistances (ASR) of these three electrodes were found to be lower in moist gases and were two orders of magnitude lower than that measured on painted Cu electrodes (see figure) . At 700°C, in 3% moist forming gas, ASR of 2.9, 3.8 and 22.7 Ω∙cm2 were calculated on the Cu electrodes with the Pd, Ru and Cu activation catalyst respectively. The microstructure of the electrodes was evaluated before and after electrochemical testing. In all cases, nano-pores were present on the as-deposited electrodes. After exposure to dry and moist reducing atmosphere at high temperatures, the microstructure of the Pd/Cu and Ru/Cu did not change significantly while major reorganisation was observed for the Cu/Cu electrode. [1] Morejudo SH, Zanón R, Escolástico S, Yuste-Tirados I, Malerød-Fjeld H, Vestre PK, et al. Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor. Science 2016;353:563–566 [2] Patki N, Ricote S, Way JD, Fabrication of reducing atmosphere electrodes (fuel electrodes) by electroless plating of copper on BaZr0.9-xCexY0.1O3-δ – a proton-conducting ceramic, submitted to International Journal of Hydrogen Energy in November 2016 Figure 1