Modulating the interfacial solvation structure to promote hydroxyl migration for alkaline hydrogen oxidation.
basic_science · Level V
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- Record sourced from PubMed, PMID 42431903.
- Also identified by DOI 10.1038/s41467-026-75394-x.
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Abstract
Alkaline hydrogen oxidation reaction (HOR) kinetics are fundamentally governed by electrode-electrolyte interfacial water structure and hydrogen-bond (H-bond) networks, yet their dynamic regulatory mechanism remains elusive. Here we show that precise modulation of the P coordination environment of Ir-based catalysts effectively enhances alkaline HOR catalytic performance. A series of Ir-based model catalysts with tunable P-coordination numbers are synthesized on nitrogen-doped carbon (NC) (IrP<sub>2</sub>-Ir<sub>2</sub>P@NC, IrP<sub>2</sub>@NC, Ir@NC). The optimal Ir-P coordination (5.1 ± 0.7) induces controlled partial dissolution of Ir cations, a dynamic phenomenon rarely exploited in alkaline HOR catalysis. This effect reconstructs the interfacial H-bond network via enriched gap-H<sub>2</sub>O and strengthened network connectivity, while optimizing hydrogen and hydroxyl adsorption to accelerate the Volmer step. The optimized IrP<sub>2</sub>-Ir<sub>2</sub>P@NC delivers a mass activity of 1.72 mA μg<sup>-1</sup> and a prominent alkaline exchange membrane fuel cell (AEMFC) peak power density of 1.59 W cm<sup>-2</sup>. Ab initio molecular dynamics simulations confirm modified solvation structure elevates interfacial H-bond density, thereby elucidating the previously unresolved mechanism by which cation dissolution dynamically templates the H-bond network for enhanced HOR performance.