Figure 7.
(a) Schematic illustration of the dynamic surface transformations induced under OER conditions. Strontium leaching and Co hopping during the initial phase of OER result in the formation of mixed phases at the catalyst surface. A dynamically evolving and catalytically active CoO(OH) phase as well as a highly insoluble and catalytically inactive La(OH)3 phase is formed. (b) Chronopotentiometric measurements for the characterization of the LSCO stability on the basis of the catalyst lifetimes at an applied current density of j = 3.0 mA·cm–2 comparing the lifetime of LSCO in 0.1 M KOH and Co-spiked 0.1 M KOH. Abrupt increase of potential denotes the end of lifetime. The catalyst lifetime is considerably increased by Co-spiking of the electrolyte.