Alternative Pathway of CO2 Hydrogenation by Lewis-Pair-Functionalized UiO-66 MOF Revealed by Metadynamics Simulations.

The reaction between H2 and CO2 catalyzed by an intramolecular frustrated Lewis pair, which is covalently bonded to a UiO-66 metal-organic framework (MOF), is considered in this work. Free energy surfaces (FESs) for this reaction are generated throughout finite-temperature density functional theory (DFT) metadynamics (MD) simulations. The simulated FESs indicate an alternative stepwise pathway for the hydrogenation of CO2. Furthermore, indications of weaker binding of CO2 than H2 to the Lewis pair centers have been observed via metadynamics simulations. These findings were unknown from the results of static-DFT calculations, which proposed a concerted reduction of CO2. The results of the present work may influence the design of new efficient heterogeneous Lewis pair (LP)-functionalized MOFs to catalyze capture and conversion of CO2 to high-value chemicals.