Dynamic Electron Spring Effect in Hollow Fe2O3/CoSe2 Heterostructure Enhance Ethanol Electro‐Oxidation Activity and Stability

Abstract Developing efficient non‐noble electrocatalysts with high activity and selectivity for ethanol oxidation reaction (EOR) across a wide potential range remains a significant challenge in hybrid energy systems. Herein, hollow Fe 2 O 3 /CoSe 2 heterostructures (H‐Fe 2 O 3 /CoSe 2 @C) via interface engineering are reported as highly effective EOR promising electrocatalysts. Characterizations reveal that Fe 2 O 3 functions as a dynamic electron spring to tune the electronic structure of Co sites, accelerating the formation of the Fe 2 O 3 /CoOOH heterostructure while suppressing Fe 2 O 3 /CoO 2 evolution. In situ Raman spectroscopy and theoretical calculation confirm that the Fe 2 O 3/ CoOOH heterostructure enhances EOR kinetics and lowers the energy barrier of the potential‐determining step. Quasi in situ X‐ray photoelectron spectroscopy further demonstrates that Fe 2 O 3 stabilizes Co 3+ against overoxidation, expanding the operational potential window. Consequently, H‐Fe 2 O 3 /CoSe 2 @C achieves outstanding EOR performance, exhibiting 10 mA cm −2 @1.30 V vs. RHE with a high faradaic efficiency of 99% at 1.30 V. Ethanol‐assisted Zn‐Air battery/water splitting devices based on H‐Fe 2 O 3 /CoSe 2 @C demonstrate enhanced energy conversion efficiency, with voltage reduced by 210 and 180 mV at 10 mA cm −2 , respectively. This work provides critical insights for designing heterostructure electrocatalysts and advancing the utilization of biomass energy.