Boosting the oxygen evolution stability and activity of a heterogeneous IrRu bimetallic coating on a WO3 nano-array electrode for PEM water electrolysis

Abstract

Designing an oxygen evolution reaction (OER) electrode with high activity and stability is critical for cutting costs. Herein, a WO₃ nano-array electrode with a heterogeneous IrRu coating is obtained via a facile electrodeposition approach, obtaining balance between OER activity and stability. The obtained IrRu@WO₃ electrode exhibits a competitive overpotential of 245 mV at 10 mA cm⁻². Based on studies via ex situ ICP, good stability is achieved, with mild Ir and Ru mass loss ratios of 9.6% and 24.4%, respectively, after 40 h of multi-step chronopotentiometry (10–100 mA cm⁻²). A single cell can attain a current density of 4.5 A cm⁻² at 2.13 V at Ir loading of 115 μg cm⁻², and the nano-array structure remains stable, with a single-cell lifetime of 500 h. Benefiting from the structure, interfacial Ru exhibits excellent OER performance and it can be secured thanks to the electrophilic electronic structure, avoiding the formation of soluble and over-oxidated Ru. A nanoarray-structure electrode is achieved with tunable stability and activity for PEM water electrolysis.