Papers by Keyword: FeVO₄

Abstract: The bamboo-like FeVO₄ nanocrystallines were synthesized by a two-step method of the microwave hydrothermal-calcination, using Fe (NO₃)₃·9H₂O and NH₄VO₃ as raw materials. The physical and photophysical properties of the as-prepared photocatalysts were fully characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), UV-vis diffuse reflectance spectra and photoluminescence (PL) analysis. The photocatalytic activities were evaluated by the decolorization of RhB solution under UV and visible light irradiation. The results reveal that the precursor solution concentration is 0.15 mol/L, the molar ratio n (Fe)/n (V) is 1, pH=3.0. The microwave hydrothermal reaction is at 180 °C for 120 min and then calcinated under 550 °C for 3 h so as to obtain the triclinic FeVO₄ nanocrystalline. Along [120] and [110], the fore and aft phases of the crystal orientation are bonded self-assembly to grow into the bamboo-like nanocrystalline with the energy gap of 2.42 eV. Under the UV-light irradiation for 240 min, the degradation rate of RhB is up to 91.2%. Adding 0.1 mL H₂O₂ to the solution, the out-phase photo-fenton reaction occurs and the degradation rate to RhB can reach to 98.8% after 8 h visible-light irradiation.

Abstract: Ferric vanadate (FeVO₄) nanoparticles as visible-light photocatalysts were successfully prepared by microwave irradiation method. The structure and morphology of FeVO₄ nanoparticles were charactered by X-ray diffraction (XRD) and scanning electron microscope (SEM). Absorption ranges, which are responsible for the observed photocatalyst behavior, were investigated. Photocatalytic activities of the synthesized samples were examined by studying the degradation of the model dyes Methylene Blue (MB) under visible-light irradiation (400 nm). Various influence factors such as heat treatment temperature of FeVO₄, and solution pH values as well as the amount of hydrogen peroxide and FeVO₄ catalyst on the photocatalytic degradation of MB were discussed. Results clearly show the degradation ratio can reach 99% under the optimal reaction conditions in dye wastewater treatment in a short photocatalytic reaction time.

Abstract: Pd/FeVO₄ composite photocatalysts were synthesized by the impregnation method.The as-prepared samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM).And the obtained samples were characterized by XRD, SEM and BET. The effect of Pd-loaded contents on their photocatalytic activity was studied by photocatalytic oxidation of methyl orange under 20 W UV light irradiation. The mechanism was also analysised. The results show that PdO can remarkably affect the photocatalytic activity.The photocatalyty activity of Pd-loaded FeVO₄ was significantly enhanced and the decolorization rate of MO can be increased 27% more than that of pure FeVO₄ sample when loading content is 3.5wt %.

Abstract: FeVO₄ photocatalysts were synthesized via a surfactant-assisted sol-gel method and characterized with X-ray diffraction (XRD), scanning electron microsoope （SEM）and specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. The XRD patterns of no-surfactant-assisted, PEG-assisted, CTAB-assisted and SDS-assisted FeVO₄, indicate that diffraction peaks can be well indexed as triclinc FeVO₄. And the crystalline sizes of samples were evaluated as 113, 69, 66, 76 nm for FVO, FVO-PEG, FVO-CATB and FVO-SDS respectively.The addition of surfactant woul greatly affect the morphology of FeVO₄ photocatalysts, which can lead to different photocatalytic activities between them. In the experimental conditions used, the PEG-assisted FeVO₄ product had a much higher photocatalytic activity (the photodegradation rate was about 77% or so in 14h) than the other three products.

Abstract: BiVO4/FeVO4 composite photocatalyst samples were prepared by calcining the mixture of FeVO4 and BiVO4 precusor which were prepared through liquid phase precipitation method for further increasing the photocatalytic efficiency of FeVO4. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microsoope（SEM）and specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. The XRD patterns indicate that BiVO4/FeVO4 composite photocatalysts consist of triclinic phase and the lattice was not distorted beacause of doping Bi. But the morphology change greatly and the specific surface area has little change. In the experimental conditions used, the optimal photocatalytic activity for all the prepared samples was reached when BiVO4 doping was 22 at%. The degradation rate of MO was increased by 20％ or so than that of pure FeVO4.