17O NMR methodology for rationalizing CO2 capture by next-generation MOFs – COMeuFs

With the increasing concentration of CO2 in the atmosphere, there is an urgent need to find new materials for carbon capture. In this context, oxygen-based sorbents are very attractive alternatives to traditional amine-based compounds, and are the object of active research. However, many aspects of their reactivity with CO2 are still unclear. 17O solid-state Nuclear Magnetic Resonance (NMR) is a spectroscopy which is highly sensitive to the local environment of oxygen, and is thus key for such investigations. Yet, to date, it has seldom been used for these applications. The COMeuFs ANR project aims at exploring CO2 adsorption in materials through a characterization methodology based on 17O NMR experiments and computational modeling, and then demonstrating the potential of 17O NMR for the study of recently proposed Metal-Organic Frameworks (MOFs) with some of them presenting pending oxygen nucleophilic sites, and which have been proposed for CO2 capture.
To achieve these goals, experimental 17O NMR spectra of a library of model compounds whose structures can represent CO2 environments after adsorption will be first recorded and analysed. Then, the CO2 chemi/physisorption in MOFs series will be followed by advanced 17O NMR experiments at high magnetic field (up to more than 28 T) and computational modeling. Information on the local dynamics at the adsorption site will also be obtained using variable-temperature analyses. Furthermore, as the adsorption of CO2 in MOFs can be altered in “real conditions” by the presence of H2O in the pores, or of other gases (e.g. CH4), competition effects on the CO2 binding sites of such disruptive molecules will also be probed by 17O NMR.
This interdisciplinary project combines teams with complementary skills (17O labeling, NMR and computational modeling). It will provide a global view of the interaction between CO2 and MOFs-in particular some of them containing pending nucleophilic oxygen groups at their surface, which is expected to be useful to improve MOFs’ CO2 adsorption capacities, and also to characterize other materials currently developed for CO2 capture.