Abstract
Recently, most of the research attention has been focused on controlling global warming resulting from the emission of greenhouse gases. The advantage of developing adsorbents for physisorption-based CO2 capture resides in the reduction of energy penalty and easier recyclability. Composite systems (MOF/GO) made from the assembly of graphene oxide (GO) with Metal organic frameworks (MOFs) together with tailored functionalities have been recently revealed as promising candidates to selectively adsorb CO2 over diverse gases including N2 and CH4. In this PhD, an innovative computational methodology integrating density functional theory calculations and force field-based molecular dynamics simulation has been applied to provide a first atomistic picture of the interactions at the MOF/GO interface with the main objective to characterize the nature of the interactions between the two components, the surface coverage, the GO conformation that all together are expected to play a key role in the compatibility of the composite. As a first step, a careful attention has been paid to develop a structural model for the GO containing –hydroxyl, -epoxy and –carboxylic groups consistent with the experimental observation on the C/O ratios. As a proof of concept, the zinc-based zeolite imidazole framework ZIF-8 has been considered and its MOF surface model has been taken from our previous work. The MOF/GO interface has been further built and detailed analysis of the MOF/GO interfaces has been generated. A systematic computational exploration of the impact of the nature of the MOFs as well as of the functionalization of GO has been further deployed. Subsequently, the adsorption and separation performances were modelled for these MOF/GO systems using Monte Carlo simulations. These computational findings were supported by experimental data collected within the frame of the H2020 EU GRAMOFON and paves way towards a more rationale development of mixed matrix membranes.