Design of Lewis Pair-Functionalized Metal Organic Frameworks for CO2 Hydrogenation

Efficient catalytic reduction of CO2 is critical for the large-scale utilization of this greenhouse gas. We have used density functional electronic structure methods to design a catalyst for producing formic acid from CO2 and H-2 via a two-step pathway having low reaction barriers. The catalyst consists of a microporous metal organic framework that is functionalized with Lewis pair moieties. These functional groups are capable of chemically binding CO2 and heterolytically dissociating H-2. Our calculations indicate that the porous framework remains stable after functionalization and chemisorption of CO2 and H-2. We have identified a low barrier pathway for simultaneous addition of hydridic and protic hydrogens to carbon and oxygen of CO2, respectively, producing a physisorbed HCOOH product in the pore. We find that activating H-2 by dissociative adsorption leads to a much lower energy pathway for hydrogenating CO2 than reacting H-2 with chemisorbed CO2. Our calculations provide design strategies for efficient catalysts for CO2 reduction.