Dynamical changes of a Ni-Fe oxide water splitting catalyst investigated at different pH

- Deactivation of the OER activity is observed in the NiFeOx catalyst in pH 7.
- Oxygen evolution activity is partly recovered when transferred back to pH 13.
- Correlations between crystallinity, composition, and activity are established.
- Limited correlation is found between the Ni redox charge and the OER activity.
- In situ DEMS analysis shows formation of degradation products at lower pH.