Fig. 1: Surface Configurations of IrO₂(110) under Anodic Conditions.
From: Oxygen evolution reaction on IrO2(110) is governed by Walden-type mechanisms
a Pourbaix diagram for IrO2(110), indicating the thermodynamically most stable surface phase as a function of applied electrode potential, U, and pH. The white dotted line represents the OER equilibrium potential, U0OER = 1.23 V vs. reversible hydrogen electrode (RHE). While a partly hydroxylated IrO2(110) surface is observed at electrode potentials exceeding the OER equilibrium potential, we consider four different surface motifs for our mechanistic studies due to their comparable energetics under OER conditions: (b) fully hydroxylated surface (2OHbr + 2 *cus-OHot), c) partly hydroxylated surface (2Obr + 2*cus-OHot), d) fully oxygen-covered surface (2Obr + 2*cus-Oot), and e) partly OOH-terminated surface (2Obr + 1*cus-OOHot 1*cus-Oot).
