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

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 Bi₂Sb_1.5. The designed Bi₂Sb_x 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.