Studies on metal organic frameworks

Abstract

An eco-friendly way of synthesizing the Metal Organic Frameworks (MOFs) is a scientific challenge and has practical difficulties. However, most of the MOFS are widely used in catalytic study and gas storage. The well-coordinated study for MOF synthesis and its methodology is still cumbersome. Aluminum fumarate (Al_FA), a nanoporous MOF is one of the most promising materials in recent years.Scalable synthesis of Al_FA MOF in an aqueous medium and the effect of drying on the crystallinity, apparent activation energy and thermal lifetime are presented. The materials oven-dried (Al_FA_A) at 100 °C (760 mm Hg) for 3 h and vacuum dried at 100 °C (25 mm Hg) for 3 h (Al_FA_C) are characterized by Fourier Transform Infrared Spectrophotometer (FTIR), Differential Scanning Calorimeter (DSC), Thermogravimetric analyzer (TG), X-ray Diffractometer (XRD), Particle Size Analyzer (PSA), Scanning Electron Microscope with Energy Dispersive Spectroscopy (SEM-EDS) and Brunauer Emmett Teller (BET) analysis. The BET surface area, micropore volume (Vpore) and mean pore diameter of Al_FA_A are 937 m2g-1, 0.38 cm3g-1 and 1.6 nm respectively. The Al_FA_A MOF is thermally stable up to 400 °C (673 K) when compared to Al_FA_C which is stable only up to 350 °C (630 K). The thermal degradation kinetics for Al_FA_A and Al_FA_C are reported for the first time using the model free and model fitting approach. The thermal degradation behaviors of Al_FA materials are investigated by TG at four different heating rates (and#946; = 5, 10, 15 and 20 K min-1). The most widely used integral methods like Flynn-Wall-Ozawa (FWO), Corrected Flynn-Wall-Ozawa (C_FWO), Kissinger-Akahira-Sunose (KAS), Corrected Kissinger-Akahira-Sunose (C_KAS), Vyazovkin (VYZ) and Advanced Vyazovkin (A_VYZ) methods are used to estimate the apparent activation energy for thermal degradation (Ea-D), pre-exponential factor along with reaction model and a thermal lifetime of the materials for various reaction extents (and#945;).