CO Adsorption Energy Match at Dual Sites Drives C-C Coupling Activity in Rare Earth-Cu CO₂ Reduction Catalysts

Due to their unique f orbitals and electrons, rare earth (RE)-doped copper-based catalysts show promise for producing specific multi-carbon products via CO₂ reduction. However, how different types of Re elements affect the key C-C coupling steps remains unclear, and as a result, RE-Cu dual-site catalysts often face challenges due to the lack of definitive design guidelines. To address this issue, we introduce a descriptor, the adsorption energy matching degree of *CO intermediates between RE and Cu sites, which enables computational screening of high-performance RE-Cu alloy catalysts. Electrochemical tests show that Cu doped with 0.16% Yb achieves remarkable stability (50 h at >1.5 A cm^-2) and selectivity (65% Faradaic efficiency for C₂H₄) in a membrane electrode assembly (MEA). In situ characterization reveals that Yb atoms substituting Cu participate in C-C coupling and promote efficient C₂H₄ production. This work establishes a design principle for highly efficient RE-doped Cu electrocatalysts.