Bismuth‑antimony bimetallic catalyst breaks activity-selectivity trade-off in electrocatalytic carbon dioxide to formate conversion.

Designing catalytic materials with enhanced selectivity and activity is crucial for sustainable electrochemical carbon dioxide reduction (COR) technologies. Bi is the most promising material for COR conversion into formate due to advantages such as its low cost, nontoxicity, and stable properties; however, it encounters critical CO activation energy barrier and hydrogen evolution reaction competition during COR. The activity of Bi-based catalysts is generally enhanced at the expense of their selectivity, leading to a seesaw relationship between activity and selectivity. Here, we report breaking the selectivity and activity limits of Bi in COR by constructing a Bi-Sb bimetallic catalyst. We demonstrated that Sb accelerates the sluggish water dissociation kinetics to exceed the activity of bulk Bi through a proton-coupled electron transfer process. Besides, a highly active Bi-Sb interface site can be generated to promote the first-step CO activation and hydrogenation process, leading to the synergistic adsorption of the *OCHO intermediate. As a result, the Faradaic efficiency of formate for Bi from 85 % at 200 mA cm enhances to 95 % at 600 mA cm for BiSb. The designed BiSb catalyst provides an avenue to achieve selectivity and active material for the electroreduction of CO into high-value-added chemicals at the industrial-current level.