| dc.description.abstract | Metal-organic frameworks (MOFs), also known as porous coordination polymers, have attracted tremendous interests due to its complicated structures and outstanding properties. The solvothermal synthetic method without stirring in an autoclave was most commonly used for the milligram scale synthesis. The reproducibility of MOFs’ properties under the different scale and addition rate have been overlooked. Therefore, the aim of this thesis was to understand the reproducibility of MOFs from different scale and synthetic methods. In this thesis, two well-known MOFs, UiO-66 and In-MIL-68 were taken into account, and four kinds of synthetic methods were fully investigated. The different synthetic methods would affect the formation mechanism of MOF’s secondary building units (SBUs), hence altering the formation rate of SBUs and nucleation rate of MOFs. Mode I was synthesized in an autoclave with no agitation and under high pressure. Therefore, the solubility of solutes was increased. However the concentration of solution did not change. The degree of supersaturation decreased. The nucleation rate was lower, and resulted in the larger crystal sizes and better crystallinity of MOF. Mode II was synthesized under the atmospheric pressure and with agitation. The concentration was the same as mode I but the solubility was lower than the one of mode I, it resulted in the higher degree of supersaturation than the one of mode I. Therefore, mode II had the higher nucleation rate, and gave the smaller crystal sizes, less crystallinity and more defects of MOF. Modes III and IV were similar to mode II, the only difference was the addition rate of ligand and precursor solution. In modes III and IV, the concentration for the added ligand and precursor were both lower than the one in mode II, but the solubility here was the same with mode II. Therefore, the degree of supersaturation for them were lower than the one of mode II. From the above results, we concluded that in UiO-66, mode I would produce the largest crystal size, crystallinity, surface area, and the coordination amount between ligands and Zr-based SBUs. Mode II would give the opposite results for UiO-66. Besides, the photoluminescence emission signals were similar for both modes I, III, and IV at around 320 nm while 385 nm for mode II, and those results also corresponded to the C1s core-level spectra from XPS. But for another kind of MOF, In-MIL-68, the properties such as crystallinity, chemical bonding, ligand amount, PL emission signal, surface area, and binding energy would not be affected too much by different synthetic processes. The only difference was shown in mode III for In-MIL-68 that cubic addition method would give the smaller crystal size at around 5 μm. As a result, we concluded that the physical properties of UiO-66 were process-dependent because the formation steps of SBUs were more complex. On the contrary, In-MIL-68 showed more uniform properties due to the simple formation mechanism of SBUs. Therefore, we concluded that In-MIL-68 was process-independent. | en_US |