چكيده به لاتين
Metal-organic frameworks have received much attention in recent years especially as newly developed porous materials. This new class of porous materials is attracting attention due to demonstrations of their large pore sizes, high apparent surface areas, and selective uptake of small molecules, and optical or magnetic responses to the inclusion of guests. As such, they possess a wide array of potential applications including materials for gas storage, gas/vapor separation, catalysis, luminescence, and drug delivery. Different synthesis methods have been utilized to prepare MOFs.
In this study, HKUST-1, Cu-BTC/Zn-BTC and Ni-BTC metal-organic frameworks (MOFs) were synthesized on Cu, Brass and Ni foam using an electrochemical synthesis technique, respectively, (Synthesis of Cu-BTC and Zn-BTC was done simultaneously). This technique allows the formation of crystal layers overgrowing the porous metals support at room temperatures and short synthesis time. In the synthesis of Cu-BTC/Zn-BTC and Ni-BTC, the influence of some important parameters such as solvent, voltage and synthesis time on the MOF production was investigated. The structure and morphology of the MOFs were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The coordination between metals (II) and carboxylate moieties of the linker has been characterized using Fourier transform infrared spectroscopy (FTIR), and the surface area of the MOFs was measured by Brunauer–Emmett–Teller (BET) nitrogen adsorption-desorption technique. After synthesis and characterizations, the performance of synthesized HKUST-1 as an electrocatalyst for oxygen reduction reaction (ORR) was studied in 0.5 M H2SO4, phosphate buffer (pH=6) (PBS6) and 0.1 M NaOH solutions, among which the best result was obtained in PBS6. At the optimum condition, the ORR was compared with an HKUST-1synthesized by a common solvothermal method (at very long time and higher temperature and pressure). The ORR results showed that in comparison to solvothermal MOF, the electrosynthesized HKUST-1 has very higher current density and lower onset potential for ORR. The performance of Ni foam and NiBTC/Ni foam for electrochemical hydrogen evolution reaction (HER) were compared by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). The results showed that NiBTC/Ni foam has more catalytic activity for HER.
