Metal–organic framework/graphene oxide composites for CO2 capture by microwave swing adsorption

Metal–organic frameworks (MOFs)/graphene oxide (GO) composites are of growing interest due to their properties which can exceed those of the pure components, including post-combustion CO2 capture. Series of composites suitable for CO2 capture under flue gas conditions based on the microporous water stable MIL-91(Ti) have been prepared with different GO contents, following two routes, in situ and post-synthetic. It was observed that the 5 wt% GO in situ composite exhibits a semi-conducting behavior, while the post-synthetic materials are insulating, even with high (20 wt%) GO content. As a consequence, this composite absorbs microwave radiation more efficiently compared to the pure MOF and post-synthetic materials. Finally, we report that CO2 desorption is much faster under microwave irradiation compared to direct electric heating on MOF/GO in situ materials, paving the way for future energy-saving microwave swing adsorption processes.