Bimetallene Oxide With Atomic Disorder and Unsaturation for Sustainable Symmetric Proton Exchange Membrane Water Electrolysis

ABSTRACT Breaking the activity–stability paradox of metal oxides is crucial for advancing the acidic oxygen evolution reaction (OER) in proton exchange membrane water electrolyzer (PEMWE). The high metal‐oxygen covalency also renders metal oxides inherently inactive for the hydrogen evolution reaction (HER), challenging the creation of economical symmetric PEMWE devices. Herein, we profile an ultrathin atomically disordered RuIr bimetallene oxide lamella by an ice salt template process for sustainable water electrolysis. Such a disordered manner is found to trigger the localized electronic states to concurrently promote HER and OER. Meanwhile, the atomically thin structure induces the coordination asymmetry/unsaturation, disrupting the Ru/Ir─O bond covalency to inhibit the unstable lattice oxygen oxidation pathway. Resultantly, the RuIr bimetallene oxide catalyst actively delivers both the OER (206 mV) and HER (36 mV) electrocatalysis with low overpotentials at 10 mA cm ⁻² in acidic electrolyte. As implemented in the symmetric PEMWE, the device showcases a low cell voltage of 1.67 V at 1 A cm ⁻² with a durable operation for 1500 h (decay: 50 µV h ⁻¹ ) under 80°C. This work opens up viable opportunities for rationalizing active and robust oxide electrocatalysts for PEMWE through atomic disorder engineering.