Effects of Ir‐Incorporation and Nanostructuring in β‐MnO 2 for an Enhanced Electrocatalytic Oxygen Evolution Reaction

We investigated the electrocatalytic properties of Ir/β‐MnO 2 , with 4.2–5.6 atomic % (at %) iridium. The Ir/β‐MnO 2 was synthesized by heating Ir/R‐MnO 2 —formed via a surfactant‐assisted (SA) method using KMnO 4 , IrCl 3 .H 2 O, and sodium dodecyl sulfate (SDS)—to 400 °C. The Ir/β‐MnO 2 (SA) was nano‐sized based on scanning and transmission electron microscopy (SEM and TEM). Using linear sweep voltammetry (LSV), 5.6 at % Ir/β‐MnO 2 (SA) exhibited an overpotential ( of 327±5 mV for the oxygen evolution reaction (OER), at 10 mA in 0.5 M H 2 SO 4 electrolyte. At 10 mA the Ir/β‐MnO 2 (SA) catalyzed the OER for 72 h at an of 534 mV. During this time there was a 12 % loss in Mn and 8 % loss in Ir from the structure. An IrO 2 catalyst exhibited an initial η of 420±7 for the OER, but after 20 h of operation at 10 mA there was a steep rise in potential (>550 mV) and 12 % loss in Ir. The enhanced activity and stability of Ir/β‐MnO 2 (SA) is attributed to the incorporation of Ir into the MnO 2 lattice during synthesis and the formation of nano‐sized particles using the SA method.