A Simple Method for Synthesizing Highly Active Amorphous Iridium Oxide for Oxygen Evolution under Acidic Conditions

Water splitting for hydrogen production has been recognized as a promising approach to store sustainable energy. The performance of this method is limited by the oxygen‐evolution reaction. Herein, an approach for synthesizing a highly active oxygen‐evolving catalyst by a one‐step, low‐cost, environmentally friendly, and easy‐to‐perform method is presented, which works by using iridium metal as the anode at a relatively high potential. The obtained IrOx/Ir interface showed an overpotential of 250 mV at 10 mA cm−2 in 0.1 m HClO4 and remained stable under electrochemical conditions. The IrOx that was mechanically separated from the surface of IrOx/Ir metal after operation showed a threefold increase in activity compared to the current benchmark IrO2 catalyst. Various characterization analyses were used to identify the structure and morphology of the catalyst, which suggested nanosized, porous, and amorphous IrOx on the surface of metallic Ir. This synthetic approach can inspire a variety of opportunities to design and synthesize efficient metal oxide‐based electrocatalysts for sustainable energy conversion and utilization. Down to the wire: Amorphous Ir oxide was synthesized on the surface of an Ir metal anode by surface oxidation at high potential (60 V). This simple synthetic method prepared the most efficient and stable Ir‐based oxygen‐evolving electrocatalyst so far, which showed high activity and remained stable under electrochemical conditions. Moreover, IrOx that was mechanically separated from the surface of IrOx/Ir after operation showed a threefold increase in activity compared to the current benchmark IrO2 catalyst.