Proton Donors Boost Interfacial Water Activation on RuO ₂ ‐Embedded RuWO _x for Durable Acidic Oxygen Evolution

Abstract

ABSTRACT The activity‐stability dilemma in acidic oxygen evolution reaction (OER) stems from a fundamental trade‐off in the interface hydrogen‐bond network: while promoting interfacial water enrichment, it often impedes efficient proton transfer. Achieving simultaneous enhancement of interfacial water accumulation and deprotonation kinetics remains a critical challenge. Herein, we design a tungsten‐stabilized ruthenium oxide heterostructure (RuWO x ‐300) that overcomes this limitation in acidic OER. The high‐valence W 6+ species induce a localized electrostatic field, which enhances interfacial water enrichment. Concurrently, the W‐O bri ‐Ru moieties serve as active Brønsted acid sites with high proton‐donor capability, accelerating surface deprotonation. As a result, RuWO x ‐300 exhibits exceptional OER performance, requiring overpotentials of only 179 and 231 mV to achieve 10 and 100 mA cm −2 , respectively, and demonstrating remarkable stability for over 4820 h at 50 mA cm −2 , surpassing commercial RuO 2 and most reported Ru‐based catalysts. Through ab initio molecular dynamics (AIMD) simulations and in situ Raman spectroscopy, we elucidate a dual‐functional mechanism: increased interfacial water coverage reduces the activation barrier for O─O bond formation, while proton‐donor‐enhanced transfer kinetics suppresses Ru dissolution. This work establishes a new design principle for highly active and stable acidic OER electrocatalysts via proton‐donor‐mediated interfacial water activation.