One-pot synthesis of MIL-101-NH2(Cr) derivatives using GdmCl as a mediator for enhanced low CO2 concentration capture

The development of metal-organic frameworks for carbon dioxide (CO2) capture has drawn considerable interest among researchers with MIL-101(Cr) gaining significance owing to its high stability. This paper investigates the one-step synthesis of MIL-101-NH2(Cr) by using guanidine hydrochloride as a mediator under relatively mild conditions (aqueous phase, reaction temperature of 120 degrees C, and without the use of mineralization agents such as hydrofluoric acid). MIL-101-NH2(Cr) not only exhibited a high specific surface area with a Lewis-base site-rich ligand but also possessed a good CO2 adsorption capacity of 3.96 mmol/g at 1 bar. Furthermore, diethylenetriamine (DETA) was loaded into MIL-101-NH2(Cr) to design a new CO2 adsorbent DETA@MIL-101-NH2(Cr). The loaded material maintained the original structure and also displayed an improved adsorption capacity of 0.29 mmol/g under low (< 0.11 bar) CO2 partial pressure. The absorbents possessed good selectivity, stability, and recyclability which make them ideal candidates for CO2 capture.