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.