Photocatalytic conversion of diluted CO2 into solar fuel is highly appealing yet still in its infancy. Herein, we demonstrate the metal‐node‐dependent performance for photoreduction of diluted CO2 by constructing Ni metal–organic framework (MOF) monolayers (Ni MOLs). In diluted CO2 (10 %), Ni MOLs exhibit a highest apparent quantum yield of 1.96 % with a CO selectivity of 96.8 %, which not only exceeds reported systems in diluted CO2 but also is superior to most catalysts in pure CO2. Whereas isostructural Co MOLs is almost inactive in diluted CO2, indicating the performance is dependent on the metal nodes. Experimental and theoretical investigations show that strong CO2 binding affinity of Ni MOLs is the crucial factor, which stabilizes the Ni‐CO2 adducts and facilitates CO2‐to‐CO conversion. Doctor node: Photocatalytic conversion of diluted CO2 with high efficiency and selectivity can be achieved on Ni metal–organic framework (MOF) monolayers (Ni MOLs). The initial adsorption of CO2 molecules is the critical step and depends on the nature of the metal node.