Engineering In-Bi Bimetallic Alloys in Bismuth-Based Electrocatalysts toward Electrocatalytic CO₂ Reduction

Single-metal catalysts in electrocatalytic reactions often face a trade-off between activity and selectivity and are prone to structural reconstruction, leading to catalytic deactivation. Here, we report an In-Bi bimetallic alloy electrocatalyst featuring multifunctional interfacial sites. In the electrocatalytic CO₂ reduction to formate, this catalyst delivers a remarkable formate selectivity of 97.8% at -700 mA cm^-2 with excellent stability over 120 h. In situ spectroscopic characterizations combined with theoretical calculations demonstrate that alloying-induced electronic reconstruction shifts the p-band center of Bi toward the Fermi level, thereby accelerating the C-H bond formation to generate the ^*OCHO intermediate. Meanwhile, the In-Bi interfacial sites regulate the strength of the hydrogen-bonding network and facilitate H₂O activation. Therefore, this bimetallic alloy design integrates electronic reconstruction and interfacial functionality, accounting for the significantly enhanced electrocatalytic performance toward the CO₂ reduction.