Papers by Author: Qiong Liu

Abstract: The N-doped Cu11O2 (VO4)6 photocatalyst was prepared using the sol-gel method. Techniques of X-ray diffraction (XRD), scanning electron microscope (SEM) have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of Methy lorange(MO) under the UV-light, the as-prepared N-doped Cu11O2 (VO4)6 exhibits higher activity than the pure Cu11O2 (VO4)6 without doped N. It found that the N-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, N/Cu molar ratio of 12%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 94.42% or so in 60min under 20W ultraviolet lamp.

Abstract: Nd-doped Cu11O2 (VO4)6 photocatalyst was synthesized by complexing Sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy Dispersive X-Ray Spectroscopy(EDX). The photocatalytic activity of Nd-doped Cu11O2 (VO4)6 was evaluated by photocatalytic degradation of methyl orange (MO) solution under UV-light. It revealed that the Nd-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, Nd/Cu molar ratio of 2%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 95.73% or so in 60min under 20W ultraviolet lamp.

Abstract: Cu₃V₂O₈ powder was prepared by the liquid phase precipitation method and characterized using XRD , SEM and BET. The photocatalytic decolorization of methyl orange in Cu₃V₂O₈ powder suspension was investigated using 20w UV light as light source．The result shows that the the liquid-phase precipitation method is a simple and effective method for Cu₃V₂O₈ powder preparation. It was found that the sample prepared with the n(V)/n(Cu)moral ratio be 2/3, pH=7 and calcinated under 750°C for 4 hours was pure triclinc Cu₃V₂O₈ phase.

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: Silver (Ag⁺) doped iron (III) vanadate (FeVO₄) samples are prepared by the precipitation method and then characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy(XPS). The photocatalytic activity under visible light is evaluated by photocatalytic degradation of methyl orange (MO) in the solution. The results show that both FeVO₄ and Ag⁺ doped FeVO₄ samples are triclinic, the later have different surface morphology, and some needle-shaped materials appear in the later. From XPS, there are more Fe²⁺ ions in Ag⁺ doped FeVO₄ sample than that in FeVO₄ one without Ag⁺. It indicates that Ag⁺ doping can increase the density of the surface oxygen vacancies of catalysts, which can act as electron traps promoting the electron-hole separation and then increase the photo-activity. The decoloration rate after Ag⁺ doping against methyl orange solution can reach about 81%, and be more about 20％ than that of pure FeVO₄.

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.