FACILE SYNTHESIS OF FUNCTIONALIZED UiO-66-TYPE MOFs FOR CO₂ ADSORPTION

The metal-organic frameworks (MOFs) UiO-66-NH₂, UiO-66-2,5-(OH)₂, UiO-66-NO₂, UiO-66-NDC, and UiO-66-BPDC were synthesized under solvothermal conditions using different functionalized organic linkers. The structures and properties of the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and nitrogen adsorption-desorption isotherms. The crystal structures of these functionalized UiO-66(Zr) forms were similar. A series of functionalized UiO-66(Zr) samples were used in the adsorption of carbon dioxide (CO₂). UiO-66-NH₂ had the highest CO₂ adsorption capacity (about 3.35 mmol g^-1) due to its small polar -NH₂ group. The performance of UiO-66-NH₂ in CO₂ adsorption at different temperatures was also determined. The amino-functionalized material possessed better adsorption properties at 273 K than at 303 K, while the CO₂ working capacity of UiO-66-NH₂ was fully recovered after cyclic regeneration.

Keywords:
metal-organic frameworks; CO₂ adsorption; UiO-66-type MOFs; UiO-66-NH₂; functionalized linker