Self‐Reconstruction Induced Electronic Metal‐Support Interaction for Modulated Cu⁺ Sites on TiO₂ Nanofibers in Electrocatalytic Nitrate Conversion

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The Cu + active sites have gained great attention in electrochemical nitrate reduction, offering a highly promising method for nitrate removal from water bodies. However, challenges arise from the instability of the Cu + state and microscopic structure over prolonged operation, limiting the selectivity and durability of Cu + ‐based electrodes. Herein, a self‐reconstructed Cu 2 O/TiO 2 nanofibers (Cu 2 O/TiO 2 NFs) catalyst, demonstrating exceptional stability over 50 cycles (12 h per cycle), a high NO 3 − ‐N removal rate of 90.2%, and N 2 selectivity of 98.7% is reported. The in situ electrochemical reduction contributes to the self‐reconstruction of Cu 2 O/TiO 2 nanofibers with stabilized Cu + sites via the electronic metal‐support interaction between TiO 2 substrates, as evidenced by in situ characterizations and theoretical simulations. Additionally, density functional theory (DFT) calculations also indicate that the well‐retained Cu + sites enhance catalytic capability by inhibiting the hydrogen evolution reaction and optimizing the binding energy of * NO on the Cu 2 O/TiO 2 NFs heterostructure surface. This work proposes an effective strategy for preserving low‐valence‐state Cu‐based catalysts with high intrinsic activity for nitrate reduction reaction (NO 3 RR), thereby advancing the prospects for sustainable nitrate remediation technologies.