Atomically dispersed Ru doped on IrOx sub-nano clusters for the 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-IrOx) sub-nano clusters, 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 50 mA cm-2 for 500 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 catalyst. In addition, operando differential electrochemical mass spectrometry (DEMS) with isotope labelling ascertain that the catalysis process follows the adsorbate evolution mechanism (AEM), corresponding to the outstanding stability.