Understanding the mechanism of assembly and function of metal-organic frameworks (MOFs) is important for the development of practical materials. Herein we report a time-resolved diffraction analysis of the kinetics of formation of a robust MOF, MFM-300(Fe), which shows high adsorption capacity for CO2 (9.55 mmol g-1 at 293 K and 20 bar). Applying the Avrami-Erofe’ev (AE) and the
two-step kinetic Finke-Watzky (FW) models to in situ high-energy synchrotron X-ray powder diffraction data obtained during the synthesis of MFM-300(Fe) enables determination of the overall activation energy of formation (50.9 kJ mol-1), the average energy of nucleation (56.7 kJ mol-1) and the average energy of autocatalytic growth (50.7 kJ mol-1). The synthesis of MFM-300(Fe) has been
scaled up by a 1000-fold, enabling the successful breakthrough separations of the CO2/N2 mixture in a packed-bed with a selectivity for CO2/N2 of 21.6. This study gives an overall understanding for the intrinsic behaviours of this MOF system, and we have determined directly the binding domains and dynamics for adsorbed CO2 molecules within the pores of MFM-300(Fe).