Structural optimization of gas diffusion electrodes loaded with LaMnO3 electrocatalysts
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In this study, gas diffusion electrodes (GDEs) with two catalyst layers were fabricated and tested for their electrode performance for oxygen reduction in an alkaline solution. The LaMnO3/carbon black catalyst layers were fabricated using a reverse micelle method to finely disperse the LaMnO3 particles onto the carbon matrices, for which commercial Ketjen Black (KB) (1270 m2 g−1) and Vulcan XC-72R (VX) (254 m2 g−1) were used. The three-layer-structured GDE with the two LaMnO3/KB and LaMnO3/VX catalyst layers exhibited a superior oxygen reduction activity when compared to that of a conventional GDE with only one LaMnO3/KB catalyst layer. Pore size distribution and gas permeability measurements revealed that the LaMnO3/VX layer was more porous and had higher gas permeability than the LaMnO3/KB layer. These results suggest that the intermediate layer of LaMnO3/VX can efficiently supply oxygen to reaction sites dispersed in the LaMnO3/KB and LaMnO3/VX catalyst layers, which consequently leads to an improvement in the electrode performance.
KeywordsGas diffusion electrode Oxygen reduction Pt-free catalyst Brine electrolysis
This study was supported by CREST of JST (Japanese Science and Technology Corporation).