Table 3 Energetic assessment of the Walden pathways (cf. Figure 4) for the OER over different surface motifs of a single-crystalline IrO2(110) electrode (cf. Figure 1b–e) by the descriptor Gmax(U) at U = 1.23 V and 1.53 V vs. RHE
From: Oxygen evolution reaction on IrO2(110) is governed by Walden-type mechanisms
Mechanisms | U = 1.23 V | U = 1.53 V | ||
|---|---|---|---|---|
Gmax(U) (eV) | Free-energy span | Gmax(U) (eV) | Free-energy span | |
Fully hydroxylated IrO2(110) surface | ||||
Mononuclear-Walden | 0.63 | *cus-OHot → *cus-OOHot | 0.12 | *cus-OHot → *cus-Oot |
Bifunctional-Walden | 0.62 | *cus-OHot + Obr → *cus-OOot + OHbr | 0.13 | *cus-OHot + Obr → *cus-Oot + Obr |
Partly hydroxylated IrO2(110) surface | ||||
Mononuclear-Walden | 0.52 | *cus-OHot → *cus-Oot | 0.22 | *cus-OHot → *cus-Oot |
Bifunctional-Walden | 0.52 | *cus-OHot + Obr → *cus-Oot + Obr | 0.22 | *cus-OHot + Obr → *cus-Oot + Obr |
Fully oxygen-covered IrO2(110) surface | ||||
Mononuclear-Walden | 0.53 | *cus-OHot → *cus-OOHot | 0.13 | *cus-OHot → *cus-Oot |
Bifunctional-Walden | 0.52 | *cus-OHot + Obr → *cus-OOot + OHbr | 0.13 | *cus-OHot + Obr → *cus-Oot + Obr |
Partly OOH-covered IrO2(110) surface | ||||
Mononuclear-Walden | 1.61 | *cus-OHot → *cus-OOHot | 1.01 | *cus-OHot → *cus-OOHot |
Bifunctional-Walden | 1.09 | *cus-OHot + Obr → *cus-OOot + Obr | 0.35 | *cus-OHot + Obr → *cus-Oot + Obr |
