Iridium Oxide Modified with Silver Single Atom for Boosting Oxygen Evolution Reaction in Acidic Media

Abstract

Electrocatalytic oxygen evolution in acidic media is crucial for promoting water splitting. Herein, we report an Ag1/IrOx single atom catalyst (SAC) with Ag single atoms embedded in an IrO2 matrix obtained through the oxidation of IrAg single atom alloy (SAA). The Ag1/IrOx SAC delivers a low overpotential of 224 mV at current density of 10 mA cm–2 and a long-term durability better than that of commercial Ir (C-Ir). DFT calculation indicates that six Ir atoms neighboring the single Ag atom exhibit a higher-valence Irx+ (x > 4) and thus lower the adsorption free energy significantly to boost the oxygen evolution process. Furthermore, the strong Ir–O bonds and low overpotential prevent the loss of the lattice oxygen in the Ag1/IrOx SAC, resulting in high oxygen evolution reaction stability.