CO binding energy has been employed as a descriptor in the catalyst design for the electrochemical CO₂ reduction reactions (CO₂RR). The reliability of the descriptor has yet been experimentally verified due to the lack of suitable methods to determine CO binding energies. In this work, we determined the standard CO adsorption enthalpies ( ) of undoped and doped oxide‐derived Cu (OD−Cu) samples, and for the first time established the correlation of with the Faradaic efficiencies (FE) for C₂₊ products. A clear volcano shaped dependence of the FE for C₂₊ products on is observed on OD−Cu catalysts prepared with the same hydrothermal durations, however, the trend becomes less clear when all catalysts investigated are taken into account. The relative abundance of Cu sites active for the CO₂‐to‐CO conversion and the further reduction of CO is identified as another key descriptor.