Inter-Doping ZrO₂-5.5RuO₂ Heterostructures for Enhanced Efficiency and Stability in Acidic Oxygen Evolution

Acid water electrolysis represents a crucial technology for the sustainable production of hydrogen. However, acidic media and high oxidation potential can lead to oxidative dissolution of catalysts (e.g., RuO₂ → soluble RuO₄), resulting in a rapid loss of active sites. Here, we present an inter-doping strategy for the construction of zirconium-ruthenium oxide heterostructure (ZrO₂-xRuO₂) through metal-organic framework confined effect and fused salt mixing method. Specifically, ZrO₂-5.5RuO₂ achieves an ultralow overpotential of 137 mV at 10 mA cm^-2, setting a new benchmark for oxygen evolution catalysts under acidic conditions. Its mass activity (337.5 A g_Ru ^-1) at 250 mV overpotential is 32.3 times that of commercial RuO₂. The catalyst also demonstrates long-term stability for 655 h, far superior to commercial RuO₂ (<6 h). The remarkable activity and stability can be attributed to the Zr─O─Ru interfacial junction, resulting in low-valence Ru sites and high-valence Zr sites. The charge redistribution optimizes the adsorption energy of reactive oxygen species and minimizes the involvement of lattice oxygen, thus leading to a significant enhancement in both activity and stability. This work provides a novel insight for addressing the activity-stability dilemma through atomic-level interface engineering, establishing a new paradigm for the large-scale application of green hydrogen energy.