Defect‐induced reconstruction: Bi _3.84 W _0.16 O _6.24 ‐derived vacancy Bi ⁰ for efficient electrocatalytic <scp> CO ₂ </scp> to <scp>HCOOH</scp>

Abstract The electrochemical reconstructed induced defective Bi structure can effectively enhance the conversion efficiency of CO 2 to HCOOH. However, the impact of initial defects in Bi‐based pre‐catalysts on their dynamic reconstruction in eCO 2 RR is still poorly understood. Herein, Bi 3.84 W 0.16 O 6.24 and Bi 2 WO 6 are used as model pre‐catalysts. During electrochemical reduction, Bi 3.84 W 0.16 O 6.24 is rapidly induced to reconstruct into Bi 0 with vacancies (v‐Bi) due to its inherent weak strain and lattice imbalance structure, while Bi 2 WO 6 reconstructs defect‐free Bi 0 (p‐Bi). The defect‐induced formation of v‐Bi exhibits a selectivity of over 90% for HCOOH across a wide potential window of 1.1 V in H‐cell and at an industrial current density of −100 to −600 mA cm −2 . Experimental and theoretical studies demonstrate that reconstructed defects in v‐Bi simultaneously increase active sites, reduce the *OCHO formation energy barrier, and enhance intermediate adsorption stability, thereby significantly improving catalytic performance. This work provides a defect‐driven design strategy for efficient CO 2 ‐to‐HCOOH conversion.