Long-life bifunctional BaSrCoFeO3/C gas diffusion electrode

In this work, several commercially available carbon black and graphitized carbon materials were first tested with respect to their thermal and electrochemical stability by thermogravimetric analysis and accelerated degradation test in 7 M KOH, respectively. KS6L and C65 were the most stable systems. Because of its more than threefold higher specific volume, carbon black C65 was selected as additive for gas diffusion electrode fabrication in order to increase poor electronic conductivity of as-prepared La0.6Ca0.4CoO3 (LCC) and Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF) bifunctional perovskite catalysts. Especially BSCF-based gas diffusion electrode exhibited outstanding stability over 3600 h during OER/ORR cycling at 10 mA cm−2 for 2.5 h each. This was attributed to optimal catalyst/carbon interaction and their exceptional corrosion stability in highly concentrated alkaline solution. Surprisingly, BSCF/C65 showed higher activity not only for OER and but also for ORR reaction compared to that of LCC/C65.

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