Insights into Carbon Dioxide Capture over Glycine‐Functionalized Metal‐Organic Frameworks‐808 from DFT Calculations

Abstract

Metal‐organic framework‐808 (MOF‐808), functionalized with amino acids, is a promising class of materials for carbon dioxide (CO2) capture. In this study, we employed density functional theory calculations to investigate the mechanism of CO2 capture by glycine‐functionalized MOF‐808 (MOF‐808‐Gly). MOF‐808 was treated with one, two, three, or four glycine molecules to investigate the effect of glycine functionalization. It is proposed that the capture reaction proceeds in a single step involving proton transfer and C–N bond formation. With increasing glycine loading, the reaction barriers decreased, whereas the observed rate increased. When considering the substitution of different tetravalent metal centers (Zr and Hf) on the MOF‐808 node, it is found that substituting these tetravalent metal centers does not affect the capture activity. The capture reaction under humid conditions was also studied by introducing explicit and implicit amounts of water. The presence of a water molecule led to reduced barriers and more stable capture product formation, indicating the enhanced performance of MOF‐808‐Gly in CO2 capture.