Dynamic reconstruction of a pearl-thread-like CoS2–CuxS interface for an enhanced oxygen evolution reaction

Abstract

Dynamic surface reconstruction offers a promising route to enhance oxygen evolution reaction (OER) activity by optimizing the adsorption of key intermediates. Here, we construct a pearl-thread-like CoS₂–Cu_xS heterostructure on copper foam (CoS₂–Cu_xS/CF) to induce in situ formation of an active CoOOH–CuO–Cu_xS interface at low potentials. In situ Raman spectroscopy confirms the dynamic transformation, while operando electrochemical impedance spectroscopy reveals accelerated charge transfer. Density functional theory calculations show that the interface engineering shifts the d-band center, enhances electron density near the Fermi level, and lowers the free energy barrier for *O to *OOH conversion from 1.78 eV (CoOOH) to 1.48 eV (CoOOH–CuO–Cu_xS). Benefiting from the reconstructed interface, CoS₂–Cu_xS/CF achieves an overpotential of 239 mV at 10 mA cm⁻² and maintains stability for over 200 h in alkaline electrolyte. This work highlights a dynamic interface strategy to promote intrinsic OER kinetics and catalyst durability.