Engineering In–Bi Bimetallic Alloys in Bismuth-Based Electrocatalysts toward Electrocatalytic CO ₂ 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 CO 2 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 H 2 O activation. Therefore, this bimetallic alloy design integrates electronic reconstruction and interfacial functionality, accounting for the significantly enhanced electrocatalytic performance toward the CO 2 reduction.