Fig. 4: Free-Energy Diagrams and Mechanistic Schemes for Walden-type OER Mechanisms.
From: Oxygen evolution reaction on IrO2(110) is governed by Walden-type mechanisms
a Free-energy diagram for the mononuclear-Walden mechanism and c bifunctional-Walden mechanism on the partly hydroxylated IrO2(110) surface at 1.23 V and 1.53 V vs. RHE. The reaction intermediates of the mechanistic cycle are labeled on the x-axis. Blue and green solid lines indicate intermediates’ free energies at 1.23 V and 1.53 V, respectively. Colored arrows indicate the free-energy span governing Gmax(U), with the respective value displayed. b, d Schematic illustration of the mononuclear-Walden and bifunctional-Walden mechanisms, as described in Section 8, on the partly hydroxylated IrO2(110) surface. Numbers next to the arrows indicate the step sequence, and each structure represents the corresponding reaction intermediate.
