Electrocatalysts for bifunctional oxygen reduction
(ORR) and oxygen evolution reaction (OER) are commonly studied under
hydrodynamic conditions, rendering the use of binders necessary to ensure the mechanical
stability of the electrode films. The presence of a binder, however, may
influence the properties of the materials under examination to an unknown
extent. Herein, we investigate the impact of Nafion on a highly active ORR/OER
catalyst consisting of MnFeNi oxide
nanoparticles supported on multi-walled carbon nanotubes. Electrochemical
studies revealed that, in addition to enhancing the mechanical stability and particle
connectivity, Nafion poses a major impact on the ORR selectivity, which
correlates with a decrease in the valence state of Mn according to X-ray
absorption spectroscopy. These findings call for awareness regarding the use of
electrode additives, since in some cases the extent of their impact on the properties
of electrode films cannot be regarded as negligible.
Nafion‐induced reduction of manganese and its impact on the electrocatalytic properties of a highly active MnFeNi oxide for bifunctional oxygen conversion
