Solution‐Combustion Engineered Shortened Co‐V Atomic Distance Promotes Direct O‐O Coupling for Synergistically Enhanced Acidic Oxygen Evolution

ABSTRACT The acidic oxygen evolution reaction (OER) remains a critical bottleneck for proton‐exchange membrane water electrolysis (PEMWE), as non‐precious alternatives typically lack sufficient intrinsic activity and operational stability. We show that one‑step solution combustion synthesis of vanadium (V)‑doped Co 3 O 4 on Ti felt, with concurrent oxygen vacancy (V O ) generation, yields a V‑Co 3 O 4 @Ti felt catalyst. V selectively substitutes octahedral Co 3+ sites, inducing Co 2+ formation and lattice contraction that shortens Co‐V bonds relative to Co‐Co bonds. This creates atomically dispersed Co‐V dual sites, confirmed by X‑ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations, which trigger direct O‐O coupling. The reaction pathway thus shifts from the scaling‑relation‑limited adsorbate evolution mechanism (AEM) to the kinetically favored oxide path mechanism (OPM), a mechanistic switch corroborated by in situ ATR‑FTIR spectroscopy. The V‑Co 3 O 4 @Ti felt catalyst delivers an overpotential of 260 mV at 10 mA cm −2 in 0.5 M H 2 SO 4 and retains >95% of its initial activity after 65 h at 100 mA cm −2 . In a PEMWE device, it achieves 500 mA cm −2 at 1.72 V and sustains stable performance for over 500 h. We establish a design principle: heteronuclear dual‐site engineering with earth‐abundant dopants overcomes activity‐stability limitations of non‐precious OER catalysts in acid media.