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

Abstract

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 H2 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 H2. Our calculations indicate that the porous framework remains stable after functionalization and chemisorption of CO2 and H2. 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 H2 by dissociative adsorption leads to a much lower energy pathway for hydrogenating CO2 than reacting H2 with chemisorbed CO2. Our calculations provide design strategies for efficient catalysts for CO2 reduction.