Raman investigation on carbonization process of metal–organic frameworks

Under inert gas flow and high temperature, carbonization of aluminum-based metal–organic frameworks (MOFs) was carried out. The formation rate of carbonized MOFs (CMOFs) was monitored by the variation of the Raman D band to G band intensity ratio with heat treatment duration. Powder x-ray diffraction (PXRD) and scanning electron microscope (SEM) techniques were used to confirm the formation of CMOFs. The activation energy was extracted from the temperature-dependent rate constants using the Arrhenius equation and correlated with the structural properties of precursor MOFs such as pore size and the number of carbon atoms per ligand. A reaction mechanism is proposed and discussed for the formation of CMOFs based on Raman observation.