Microwave‐Assisted Synthesis of IrNi Electrocatalysts for the Oxygen Evolution Reaction in Acidic Electrolyte

Abstract

This study investigates a microwave‐assisted synthesis method for producing IrNi bimetallic catalysts for the oxygen evolution reaction in acidic environment. Due to the high cost of iridium‐based catalysts used in the anodes of proton‐exchange membrane electrolyzers, reducing the noble metal content while maintaining high performance is crucial. In this work, materials with various IrNi atomic ratios are synthesized and their impact on the catalyst microstructure, phase composition, and electrochemical performance is evaluated. The results reveal a synergistic effect between the two metals, with 60 at% Ni identified as the optimal nominal composition. This catalyst achieves an overpotential of 274 mV at 10 mA cm −2 and a Tafel slope of 49 mV dec −1 in 0.5 M H 2 SO 4 electrolyte, outperforming commercial IrO 2 (320 mV at 10 mA cm −2 and 56 mV dec −1 ). The higher activity is retained after both a 6 h chronoamperometry and an accelerated degradation test, during which Ni acts as a sacrificial component and the electrochemically surface area of the films increases. Overall, this study demonstrates the potential of microwave‐assisted synthesis, a greener and faster alternative to conventional methods, for developing low Ir‐content catalysts with enhanced performance.