كليدواژه :
Metal , Organic Framework (MOF) , Quantum Dot (QD) , QD , MOF Composites , Photocatalyst
چكيده فارسي :
Composites of Metal-Organic Frameworks (MOFs) combined with Quantum Dots (QDs) enable high photocatalytic ability. MOFs have been used as excellent photocatalysts due to their unique structure and properties such as high porosity, large internal surface area, and abundant active sites. In combination with other materials, the photocatalytic ability of MOFs can be increased. Due to quantum confinement effects, QDs have excellent photocatalytic performance. The combination of the high surface areas, microporosity and tuneable compositions of metalorganic frameworks (MOFs) with the desirable photophysical behavior of semiconductor nanoparticles or quantum dots (QDs), allows the preparation of composite materials with enhanced properties for applications in photocatalysis, energy and gas storage and sensing. These QD/MOF composites are an emergent class of materials. In this study, the new CdS/HKUST-1 composite was successfully prepared. At first, HKUST-1 was synthesized as MOF by the hydrothermal method. To prepare copper benzene tricarboxylate (Cu₃(BTC)₂ or HKUST-1), Cu(NO₃)₂.3H₂O was dissolved in H₂O (solution A) and BTC was dissolved in ethanol (solution B). After that, solution A was added to solution B and the mixture was stirred for 30 minutes. The mixture was transferred to an autoclave and heated under hydrothermal conditions to a temperature of 120°C for 12 hours. Blue precipitates were collected by washing with ethanol/water solution (volume ratio 50:50) and dried in a vacuum oven at 60°C. After that, to prepare the CdS/HKUST-1 composite, first, cadmium acetate was dissolved in ethanol; Then pre-prepared HKUST-1 was added and subjected to sonication. After that, a thioacetamide aqueous solution was added to it. Then the precipitates were filtered and washed with water and ethanol. Finally, the product was dried in a vacuum oven and the CdS/HKUST-1 composite was obtained. The synthesized composite was fully analyzed and identified using XRD, FTIR, FESEM, TEM, EDX, DRS and BET techniques. Ultraviolet-visible (UV) spectroscopy was used to investigate the photocatalytic properties of this composite. This composite was used as a photocatalyst for the removal and degradation of methylene blue dye as well as the removal and degradation of tetracycline drugs from water sources. To prepare methylene blue solution, at first, a stock solution with a concentration of 〖10〗^(-3) M was made and then a solution with a concentration of 8 ppm was prepared from the stock solution. This concentration was the optimal concentration to investigate the removal and destruction of methylene blue. To prepare the tetracycline solution, the concentration of 0.8mM was the optimal concentration.
