Effect of structural variation on the thermal degradation of nanoporous aluminum fumarate metal organic framework (MOF).

Autor: Sundari, S. Siva Kaylasa, Rishwana, S. Shamim, Kotresh, T. M., Ramani, R., Shekar, R. Indu, Vijayakumar, C. T.
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Zdroj: Journal of Thermal Analysis & Calorimetry; Apr2022, Vol. 147 Issue 8, p5067-5085, 19p
Abstrakt: Scalable synthesis of aluminum fumarate (Al_FA) metal organic framework (MOF) in aqueous medium and the effect of drying on the crystallinity, apparent activation energy and thermal lifetime are presented. The oven dried (Al_FA_A) at 100 °C (760 mmHg) for 3 h is characterized by Fourier transform infrared spectrophotometer, differential scanning calorimeter, thermogravimetric analyzer, X-ray diffractometer, particle size analyzer, scanning electron microscope (SEM-EDAX) and Brunauer–Emmett–Teller (BET) analysis. The BET surface area, micropore volume (Vpore) and mean pore diameter of Al_FA_A are 937 m2 g−1, 0.38 cm3 g−1 and 1.6 nm, respectively. The Al_FA_A MOF is thermally stable up to 400 °C when compared to aluminum fumarate dried in vacuum oven at 100 °C (25 mmHg) for 3 h (Al_FA_C) which is stable only up to 350 °C. The thermal degradation kinetics for Al_FA_A and Al_FA_C are reported for the first time using model-free approach. For the reaction extent α = 0.2–0.4, a progressive increase in the apparent activation energy for thermal degradation (Ea–D) for Al_FA_A is noted and found to be 205–220 kJ mol−1 and is constant after α = 0.4. The material Al_FA_C shows Ea–D from 160 to 173 kJ mol−1 for α values from 0.2 to 0.7. The difference in the Ea–D values between these materials is attributed to the structural changes and change in the crystalline nature of MOFs. During thermal degradation of Al_FA MOFs, gases like CO, CO2, H2O, CH2=CH2 and CH≡CH are evolved. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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