Tin Alloying Enhances Catalytic Selectivity of Copper Surface: A Mechanistic Study Based on First-Principles...

The Cu-Sn binary catalysts are found to selectively reduce CO₂ to CO electrochemically with promising efficiencies. The issue of active sites is not resolved yet. In this paper, first-principles calculations are performed to study the stability, as well as the hydrogen evolution and the CO₂ reduction properties, of the Sn-modified Cu surfaces. It is revealed that a special type of Cu step edges with inner atoms substituted by Sn single atoms can not only keep the CO₂ reduction property of a pure Cu edge but also inhibit the H₂ formation, while being stable enough under reduction conditions. By analyzing the electronic properties of the edges, we found that the Sn atom among many others can make the most optimized effect in enhancing the catalytic selectivity of the Cu surface.