Ru-RuO2 nano-heterostructures stabilized by the sacrificing oxidation strategy of Mn3O4 substrate for boosting acidic oxygen evolution reaction

Designing anodic electrocatalysts with high activity and robust stability for acidic oxygen evolution reaction (OER) is significant for the large-scale promotion of sustainable proton exchange membrane water electrolysis (PEMWE). Most reported Ru-based electrocatalysts tend to further improve activity at the expense of stability. Herein, we report the synthesis of crystalline Mn3O4 supported Ru-RuO2 nano-heterostructures as the anodic electrocatalyst that only requires a low overpotential of 182 mV (10 mA cm-2) for acidic OER, accompanied with a record stability of 400 h in 0.5 M H2SO4. The results of XPS, ICP-MS, and XAS indicate that the Mn3O4 substrate plays a crucial role in stabilizing Ru-RuO2 nano-heterostructure by preventing Ru from over-oxidation and dissolution. Meanwhile, DEMS with isotope labeling reveals that the Ru-RuO2 nano-heterostructure contributes to suppressing lattice oxygen oxidation mechanism (LOM) and concurrently expediting the involvement of adsorbate evolution mechanism (AEM) for boosting the acidic OER performance.