Piezo-photocatalysis coupling in BiFeO3–CeO2 heterojunction with off-site dual-active centers for ultrafast heterogeneous Fenton-like reactions

Efficient interfacial charge transfer is crucial for enhancing the kinetics of heterogeneous Fenton-like reactions. This study presents a dynamic modulation strategy for the off-site Ce-Fe dual-active centers (spatially separated Ce and Fe sites across the heterojunction interface) in BiFeO 3 –CeO 2 heterojunction via the piezo-photocatalysis, which facilitates the ultrafast hydrogen peroxide (H 2 O 2 ) activation. Under the synergistic piezo-photocatalytic condition, this system achieved over 90% degradation of sodium butyl xanthate (10 mg/L) within 3 min, with an apparent kinetic constant (0.43 min −1 ) three times higher than that of the Fenton-like process alone. Simultaneously, a remarkable hydroxyl radical (•OH) yield of 387.84μmol g −1 h −1 was attained, representing a 10-fold enhancement over the conventional system. In-situ piezoresponse force microscopy and electrochemical analyses reveal that the piezoelectric polarization couples with the built-in electric field, creating a potent directional field at the interface that drives the efficient charge migration. This process not only promotes H 2 O 2 reduction on the CeO 2 surface but also establishes a rapid valence cycle between Ce 3+ /Ce 4+ and Fe 2+ /Fe 3+ . This work elucidates the mechanism of external-field-mediated electronic structure regulation at the heterojunction interface at the atomic/molecular level, providing a novel approach for designing high-performance catalytic systems through surface and interface engineering.