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 (CO2R) technologies. Bi is the most promising material for CO2R conversion into formate due to advantages such as its low cost, nontoxicity, and stable properties; however, it encounters critical CO2 activation energy barrier and hydrogen evolution reaction competition during CO2R. 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 CO2R 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 CO2 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-2 enhances to 95 % at 600 mA cm-2 for Bi2Sb1.5. The designed Bi2Sbx catalyst provides an avenue to achieve selectivity and active material for the electroreduction of CO2 into high-value-added chemicals at the industrial-current level.