Fig. 2
From: Atomically dispersed hybrid nickel-iridium sites for photoelectrocatalysis
Photoelectrochemical tests. a OER activity of the H-NiOx/Ir-anion with a stepwise increase of Ir-anion solution concentration. b MOx-modified hematite exhibits significant activity difference (Δj) upon dripping the Ir-anion-containing solution. c The correlation between the hole accumulation capacity of H-MOx before the addition of Ir-anion (Supplementary Fig. 9) and the activity difference Δj after the introduction of 1.0 µM Ir-anion relative to the Ir-anion-free electrolytes. The gray arrow shows the decreased capacity of H-NiOx from 0.64 to 0.35 mC cm−2 (gray square) after the introduction of Ir-anion to the electrolyte. Error bars represent the standard deviation. d Proposed reaction paths explaining the different roles of TiOx and NiOx for the OER
