Facile synthesis of MOF 235 and its superior photocatalytic capability under visible light irradiation

Abstract

The potential of synthesized MOF 235 crystals using a microwave-assisted method was presented, with the advantages of a short reaction time and easy procedure. The as-prepared sample (MA-MOF 235) was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS) and N₂ adsorption–desorption isotherm. Meanwhile, the photocatalytic activity of the prepared sample for the degradation of rhodamine B (RhB) under visible light irradiation was also investigated. For comparison, the MOF 235 crystals were also prepared by a conventional solvothermal method, and the ST-MOF 235 was obtained and characterized. The photocatalytic results show that both MA-MOF 235 and ST-MOF 235 exhibit excellent activity for RhB degradation, and they could completely decompose the 40 μmol L⁻¹ RhB in the presence of 1 mmol H₂O₂ under visible light irradiation within 20 min. The RhB degradation over both synthesized samples followed first-order kinetics. Moreover, MA-MOF 235 showed a very stable activity for RhB degradation and without significant loss of photocatalytic activity after three consecutive usages. The microwave-assisted method is characterized with speed, highly efficiently and the as-prepared MA-MOF 235 exhibits high visible-light-driven photocatalytic efficiency for organic pollutant degradation in comparison with other MOF-based photocatalysts. Therefore, the as-prepared photocatalyst would have great potential for environmental purification.