High-Entropy Alloy Electron-Penetrated Nitrogen-Doped Carbon Interface Breaking Activity–Stability Trade-off in Acidic Oxygen Reduction to H₂O₂

The electrocatalytic two-electron oxygen reduction reaction (2e^- ORR) has emerged as an environmentally friendly approach for on-demand H₂O₂ production. In acidic H₂O₂ electrosynthesis, the active interfaces react with both oxygen-containing intermediates and oxidative acid, resulting in an activity-stability trade-off. Herein, we propose to construct a high-entropy alloy electron-penetrated and stable nitrogen-doped carbon interface for acidic electrosynthesis of H₂O₂. As a proof of concept, a typical catalyst with the MoNiCuCoIn high-entropy alloy encapsulated in few-layer nitrogen-doped carbon (MoNiCuCoIn@CN) is developed. The experimental results and theoretical calculations confirm that the MoNiCuCoIn core activates the outer carbon layer via interfacial electronic penetration, which generates optimal adsorption of an oxygen-involved intermediate and thus high 2e^- ORR activity. The robustness of the catalyst structure of MoNiCuCoIn@CN ensures remarkable 2e^- ORR stability in acid. Therefore, the catalyst delivers a record-high acidic performance with a H₂O₂ Faradaic efficiency (FE_H2O2) of >90% from -50 to -300 mA cm^-2 and a sustained FE_H2O₂ of up to 120 h at a high current density of -250 mA cm^-2. This work highlights the multimetal-carbon interface for addressing the activity-stability trade-off in harsh electrocatalysis, providing fundamental insights for the design of a next-generation catalyst.