Product-Specific Active Site Motifs of Cu for Electrochemical CO₂ Reduction

Electrochemical CO₂ reduction (CO₂R) to fuels is a promising route to close the anthropogenic carbon cycle and store renewable energy. Cu is the only metal catalyst that produces C₂₊ fuels, yet challenges remain in the improvement of electrosynthesis pathways for highly selective fuel production. To achieve this, mechanistically understanding CO₂R on Cu, particularly identifying the product-specific active sites, is crucial. We rationally designed and fabricated nine large-area single-crystal Cu foils with various surface orientations as electrocatalysts and monitored their surface reconstructions using operando grazing incidence X-ray diffraction (GIXRD) and electron back-scattered diffraction (EBSD). We quantitatively established correlations between the Cu atomic configurations and the selectivities toward multiple products and provide a paradigm to understand the structure-function correlation in catalysis.