Nickel Metal-Organic Framework Monolayers for Photoreduction of Diluted CO2 : Metal-Node-Dependent Activity and Selectivity.

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.