It was tried to disperse LaMnO3+δ oxide finely on carbon black support through a reverse micelle (RM) method using poly(oxyethylene)5 nonylphenyl ether (surfactant), and cyclohexane (solvent). An RM dispersion containing a nanosized precursor of the oxide [RM (C)] was prepared by mixing an RM dispersion containing nitrates of constituent metals [RM (A)] with another dispersion containing N(CH3)4OH. RM (C) was easily destabilized with the addition of ethanol to deposit the precursor, which was converted to hexagonal oxide (LaMnO3.15) or orthorhombic oxide (LaMnO3.00) by calcination in air or N2, respectively. Carbon black powder was mixed at various stages of these preparation procedures. Among the resulting carbon-supported oxide powders, the one for which the carbon black was suspended into RM (A) was found to give an outstanding cathodic activity: It allowed current density as high as 300 mA cm-2 at -80 mV (vs. Hg/HgO) in 8 M KOH at 60°C under air flow. Transmission electron microscope observation revealed that fine dispersion of the oxide particles in the carbon matrix is the origin of such high activity.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry