Abstract
NiFe-(Oxy)hydroxide is one of the most active electrocatalysts for the oxygen evolution reaction (OER) in alkaline conditions. Herein we investigated the stability of NiFe-(oxy)hydroxide anodes at high current densities (100 mA cm-2) at different temperatures (25, 75 °C) and base concentrations (1, 5, 10 M KOH). While polarization led to minor structural and compositional changes under standard conditions (25 °C, 1 M KOH), the anodes were severely impacted at higher temperature (75 °C) and base concentrations (5, 10 M KOH). Overall leaching and preferential leaching of Fe (resulting in a lower Fe/Ni ratio) led to decreased OER performance and increased charge transfer resistance for the samples tested at industrially relevant conditions. A dramatic loss in the catalytic activity occurred for the sample polarized at 75 °C in 10 M KOH: besides extensive leaching, a transformation of Ni(OH)2 into NiO was noted in this case. For pure NiOxHy, incorporation of Fe impurities from the electrolyte during polarization at 75 °C in 5 M KOH led to an improvement in the catalytic activity and charge-transfer properties, approaching the performance of NiFeOxHy.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 5593-5601 |
| Number of pages | 9 |
| Journal | Catalysis Science and Technology |
| Volume | 10 |
| Issue number | 16 |
| DOIs | |
| State | Published - Jul 17 2020 |
Bibliographical note
KAUST Repository Item: Exported on 2020-11-10Acknowledgements: The authors thank Adelheid Elemans-Mehring for ICP-OES measurements. M. E. C. P. acknowledges funding by a Graduate School program from the Netherlands Organization for Scientific Research (NWO). A. G. and E. J. M. H. acknowledge funding from an NWO Vici grant.