Regulation of the adsorption affinity of metal-organic framework MIL-101 via a TiO2 coating strategy for high capacity adsorption and efficient photocatalysis

Abstract

TiO2-MIL-101 nano-composite was synthesized through the growth of TiO2 crystals on MIL-101 substrate under solvothermal conditions, and was applied into the adsorption and photocatalytic degradation of methylene blue (MB), rhodamine B (RhB) and crystal violet (CV). The fabricated TiO2-MIL-101 nano-composite was characterized by thermogravimetric analysis (TGA), X-ray diffractometry (XRD), fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDAX), scanning electron microscope (SEM), transmission electron microscopy (TEM) and N2 adsorption experiments. As a result, we found that TiO2-MIL-101 nano-composite remained good porosity because of the MIL-101 substrate, and the TiO2 crystals were coated on the surface of MIL-101 without agglomeration. Furthermore, on basis of experiments, remarkable enhancement of adsorption affinity of TiO2-MIL-101 towards MB, RhB and CV could be mainly attributed to the regulation of the surface charge compared to original MIL-101 materials after coated by TiO2 crystals. Meanwhile, the fabricated TiO2-MIL-101 exhibited excellent photocatalytic activity for the degradation of MB, RhB and CV based on the TiO2 coatings.