▎ 摘　　要

Understanding the competition between the activity and selectivity allows us to rationally design catalysts for CO2 reduction to lower CO2 emission and mitigate the energy crisis. Herein, via the first-principles calculations, we enable to access the activity and selectivity of CO2 reduction on metal- and nitrogen-codoped graphene. It is found that the adsorption strength of the reaction intermediates is governed by the coordination environments of the doped metal atoms, causing a significant activity difference between different metal dopants. The adsorption free energy of CO was identified as a practical descriptor of the activity of both CO2 reduction and hydrogen evolution reaction (HER) according to the constructed linear relationship, which provides guidance for achieving the high CO2 reduction activity and the selectivity to CO simultaneously. Our finding is insightful for developing highly effective reduction catalysts based on the codoped carbon materials.