Modifying BiVO₄ with metal-organic frameworks for enhanced photocatalytic activity under visible light

A new composite photocatalyst, viz., BiVO₄/MIL-53(Fe), was prepared through a simple hydrothermal approach and characterized by means of X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy, N₂ absorption-desorption and UV-visual diffuse reflectance spectroscopy. The photocatalytic activity of prepared BiVO₄/MIL-53(Fe) catalysts was investigated in the degradation of RhB as a simulated pollutant and a possible reaction mechanism for the photocatalytic degradation of RhB was then proposed. The results indicate that after modifying BiVO₄ with metal-organic frameworks (MOFs), the surface area of BiVO₄/MIL-53(Fe) is improved greatly; moreover, the BiVO₄/MIL-53(Fe) composite also exhibits much higher photocatalytic activity than pristine BiVO₄ and MIL-53(Fe). In particular, the photocatalytic activity of BF-2 composite is about 5.2 and 8.1 times higher than those of pure MIL-53 (Fe) and BiVO₄, respectively. In addition, BiVO₄/MIL-53(Fe) composite photocatalyst is rather stable and can keep its photocatalytic activity and structure after four recycling tests.