Transient Heterojunction‐Mediated Dual‐Mode Charge Separation in Na‐Modified NiFe 2 O 4 /ZnO Under Mechanical and Optical Excitation

Efficient charge separation across dynamic semiconductor interfaces remains a key challenge in both mechanically driven and photocatalytic systems. Herein, we present a Na‐modified NiFe 2 O 4 (Na‐NFO)/ZnO platform as a model system for investigating transient heterojunction‐like interfacial coupling under mechanical and optical excitation. Na‐related modification enhances the mechanically responsive oxidation behavior of NiFe 2 O 4 while preserving its semiconducting character and broadband light absorption. ZnO serves as a wide‐bandgap semiconductor counterpart with intrinsic piezoelectricity and may participate in interfacial charge redistribution during repeated particle contact. Under mechanical stimulation, the oxidation performance of Na‐NFO increases with measured Na content, and ZnO‐assisted systems outperform those using insulating collision partners. Under UV‐filtered optical excitation, the physically mixed Na‐NFO/ZnO system exhibits photoluminescence quenching and higher oxidation performance than either component alone. These observations are consistent with the possibility that repeated dynamic contact produces transient heterojunction‐like interfacial coupling that contributes to improved charge separation under both excitation modes. This study suggests that dynamically regenerated semiconductor–semiconductor interfaces may provide a useful strategy for enhancing dual‐mode semiconductor catalysis.