Atomically dispersed Ru doped on IrOx sub-nanoclusters for enhanced oxygen evolution reaction in acidic media

Abstract

High-performance anodic electrocatalysts are urgently required for proton exchange membrane (PEM)-based water electrolysis. Here, a simple one-step approach is introduced to produce atomically dispersed Ru on iridium oxide (Ru-IrO_x) sub-nanoclusters, aiming to simultaneously enhance the activity and durability of the electrocatalyst toward acidic oxygen evolution reaction (OER). The resulting catalyst shows a low overpotential (η) of 237 mV at 10 mA cm⁻² in acidic media and demonstrates exceptional durability by sustaining a constant current of 100 mA cm⁻² for 150 hours. Real-time electrochemical impedance spectroscopy (EIS) measurements and in situ Raman spectra unveil the formation of a further oxidized layer on the surface that prevents the degradation of the catalyst. In addition, operando differential electrochemical mass spectrometry (DEMS) coupled with isotope labelling measurements ascertains that the catalysis process follows the adsorbate evolution mechanism (AEM), corresponding to outstanding stability.