Synthesis and Evaluation of Graphene Aerogel-Supported Mn_xFe_3-xO₄ for Oxygen Reduction in Urea/O₂ Fuel Cells.

ABSTRACT: Graphene aerogel-supported manganese ferrite (Mn_xFe_3-xO₄/GAs) and reduced-graphene oxide/manganese ferrite composite (MnFe₂O₄/rGO) were synthesized and studied as cathode catalysts for oxygen reduction reactions in urea/O₂ fuel cells. MnFe₂O₄/GAs exhibited a 3D framework with a continuous macroporous structure. Among the investigated Fe/Mn ratios, the more positive oxygen reduction onset potential was observed with Fe/Mn=2/1. The half-wave potential of MnFe₂O₄/GAs was considerably more positive than that of MnFe₂O₄/rGO and comparable with that of Pt/C, while the stability of MnFe₂O₄/GAs significantly higher than that of Pt/C. The best urea/O₂ fuel cell performance was also observed with the MnFe₂O₄/GAs. The MnFe₂O₄/GAs exhibited an OCV of 0.713 V and a maximum power density of 1.7 mW cm^-2 at 60 °C. Thus, this work shows that 3D structured graphene aerogel-supported MnFe₂O₄ catalysts can be used as an efficient cathode material for alkaline fuel cells.

SUBMITTER: Bejigo KS 

PROVIDER: S-EPMC6515475 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature