Electrified interfacial oxygen-down water boosts efficient and durable electrolysis

The oxygen evolution reaction proceeds through proton-coupled electron transfers, mastering interfacial proton dynamics is therefore the critical nexus for simultaneously achieving high catalytic activity and long-term stability. Herein, we establish an oxygen-down water adlayer (H₂O ↓ ) that concurrently optimizing initial water deprotonation and subsequent proton transport. We engineer edge dislocations into RuO₂ to create stress fields that exert differential electrostatic forces on water, anchoring oxygen while repelling protons and thereby enforcing the H₂O↓ orientation, which is directly evidenced by a molecular dipole angle (θ_w) of ~67°at 1669 cm^-1 peak in infrared spectroscopy. In situ spectroscopy and simulations confirm that the H₂O↓ layer forms a rigid hydrogen-bond network that accelerates Grotthuss-like proton shuttling, preventing corrosive local acid accumulation. The pre-aligned water molecules bypass the stochastic reorientation step, reducing the oxygen formation barrier from 2.02 eV to as low as 0.85 eV. Consequently, our RuO₂ catalyst achieves 10 mA cm^-2 at 179 mV overpotential with >1,000-hour stability, and enables high current density at 1 A cm^-2 for >720 hours at 1.75 V.