Synthesis, surface properties and optical characteristics of CuV2O6 nanofibers

In3+-doped CuV2O6 nanofibers were prepared via the hydrothermal synthesis method, which produced fibers with a typical diameter of 100 nm, and a length of 1-5 μm. The nanofibers grew in a preferred [020] direction. The crystal phase together with the structure was studied via X-ray polycrystalline diffraction (XRD) and the Rietveld refinement. The surface characteristics of this nanostructure were measured with a scanning electron microscope (SEM), energy dispersive spectra (EDS), transmission electron microscopy (TEM), and N2-adsorption-desorption isotherms. Photo-activities were evaluated by optical absorption, luminescence, and decay behaviors. The band-gap structures and positions were investigated. The vanadate has an efficient optical absorption from the UV to the visible wavelength region with an indirect allowed transition characterized by the narrow gap energy of 1.96 eV. The photocatalysis was investigated by the photo-degradation of RhB solutions irradiated by visible light. Correspondingly, CuV2O6:In3+ nanofibers possess quenched luminescence and have a more efficient photocatalytic activity on the RhB degradation. Photocatalytic mechanisms were proposed based on the experimental results, the band-energy positions, and the trapping experiments. The coexistence of V4+/V5+ ions and induced-color centers was discussed on the proposed photocatalytic mechanism. The results demonstrated the promising potency of such In3+-doped CuV2O6 nanofibers for technological applications due to their high photo-activity and good cycling performance with the fiber morphology.