Modulating electronic structure and hydrogen bond network via asymmetric S–Ru–O interfaces for superior alkaline hydrogen oxidation catalysis

Abstract

Triggering structural asymmetry can induce charge redistribution and modify electronic structures, which is of great significance for the design of high-performance hydrogen oxidation reaction (HOR) electrocatalysts. Herein, we propose a dual anion-induced strategy to create an innovative RuS₂-RuO₂ heterostructure featuring abundant S–Ru–O interfaces (RuS₂-RuO₂@C). This RuS₂-RuO₂@C demonstrates an impressive mass activity of 2.61 mA ${\mu g}_{Ru}^{-1}$ and an exchange current density of 2.96 mA cm⁻², surpassing Pt/C and other comparative samples by over 20 times. Durability assessments confirm the superior stability of RuS₂-RuO₂@C, with only minimal performance loss during operation. Density functional theory (DFT) calculations indicate that the asymmetric S–Ru–O configuration optimizes the interfacial electronic structure and shifts the d-band center closer to the Fermi level, effectively reducing the energy barrier of the rate-determining step (RDS) in the alkaline HOR process. Moreover, in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) characteristics disclose the formation of a substantial hydrogen bond network at the S–Ru–O interface, which aids in the desorption of H₂O_ad and facilitates the vital Volmer step in the HOR pathway.