Search

This study aims to synthesize and evaluate the photocatalytic activity of bismuth terephthalate material (Bi-BDC) synthesized by solvothermal (ST) and microwave-assisted solvothermal (MW) methods. Differences in the crystal structure and crystal shape were assessed by analytical methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectrum, X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption, Raman spectrum, and thermal gravimetric analysis (TGA). From XRD, IR, Raman, and XPS results, the fully crystallized Bi-BDC materials were achieved regardless of the preparation router. Bi-BDC-MW exhibited spherical-like morphologies, producing between stacked lamellar, while Bi-BDC-ST method exhibited a heterogeneous structure. The TGA data indicated that Bi-BDC is thermally stable up to 300 °C, suggesting the excellent thermal stability of Bi-BDC. The surface area and pore volume of Bi-BDC-MW (18 m2/g and 85 × 10−3 cm3/g) are higher than those of Bi-BDC-ST (16 m2/g and 52 × 10−3 cm3/g), which is due to its well-defined lamellar microstructure and homogeneity of the crystals. Compared to Bi-BDC-ST, Bi-BDC-MW has a higher value in the content of oxygen vacancy. Moreover, the photocatalytic efficiency of Bi-BDC-MW was significantly higher than that of Bi-BDC-ST, in which 99.44% rhodamine B (RhB) is removed after 360 min of irradiation. The improved photocatalytic efficiency of Bi-BDC-MW is ascribed to the morphology, specific surface area, and oxygen defects, which exhibited the good separation of electrons and holes, as confirmed by the photoluminescence (PL). The results should open a new approach to enhancing the photocatalytic activity of bismuth terephthalate materials. [ABSTRACT FROM AUTHOR]

Nano Fe-BTC/graphene oxide (GO) composites were successfully synthesized by hydrothermal treatment with a microwave-assisted method. Samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption–desorption, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and Ultraviolet–visible diffuse reflection spectroscopy (UV–Vis DRS). SEM image of Fe-BTC/GO-30 showed the particle size of 30–50 nm on the GO surface. From the UV–Vis diffuse reflectance spectra, it revealed that nano Fe-BTC/GO composite absorbed the wavelengths in the visible light region with a low bandgap energy of 2.2–2.45 eV. Fe-BTC/GO nanocomposites were tested for the photocatalytic degradation of reactive yellow 145 (RY-145) in aqueous solution. Fe-BTC/GO composites exhibited high photocatalytic activity. Thus, at pH of 3 and high initial concentration of 100 mg RY-145/L, removal efficiency reached the value of 98.18% after 60 min. of reaction. In comparison with Fe-BTC/GO synthesized by the solvothermal method, nano Fe-BTC/GO showed much higher RY-145 removal efficiency. Moreover, this Fe-BTC/GO-30 showed high catalytic activity stability and could be reused, opening the high potential application of this promising photo-Fenton catalyst in photocatalytic degradation of organic pollutants from aqueous solution. [ABSTRACT FROM AUTHOR]