Wen-Xiu Liu

University of Science and Technology, Beijing, Peping, Beijing, China

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Publications (4)6.3 Total impact

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    ABSTRACT: A visible-light-active nitrogen doped nanocrystalline titanium dioxide (N-TiO2) hydrosol was prepared by precipitation-peptization method and following with hydrothermal crystallization at 110 degrees C holding for 6 h. XPS results show that nitrogen ions have been doped into the TiO2 lattice successfully and the UV-Vis absorption spectra indicate that the light absorption edge of the N-doped TiO2 has been red-shifted into visible light region. The photocatalytic performance of the N-doped TiO2 thin film prepared from the synthesized hydrosol was evaluated by photodegrading the gaseous formaldehyde (HCHO) under visible light irradiation. The photodegradation ratio of HCHO reached up to 90% within 24 h and the degradation ratio was stable for ten degradation cycles, indicating the prepared hydrosol has good reusable performance in photodegrading gaseous pollutants.
    Solid State Sciences 07/2014; 33. DOI:10.1016/j.solidstatesciences.2014.04.012 · 1.68 Impact Factor
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    ABSTRACT: The photo-degradation of formaldehyde (HCHO) by nitrogen-doped nanocrystalline TiO2 (N-TiO2) powders under visible light irradiation has been systematically investigated. Experimental results show that the degradation ratio reached up to 42.6% after 2 h visible light irradiation when the amounts of N-TiO2 powders were 0.5 g, the initial concentration of the HCHO was set at 0.98 mg/m3, the illumination intensity was fixed at 10,000 lux, the ambient temperature was set at 26 °C, and the relative humidity was maintained at 33 ± 5%. Further research shows that the degradation ratios were all larger than 40% in ten repeated cycles of photodegradation of HCHO by N-TiO2 powders. The degradation ratio was as high as 82.9% after 2 h visible light irradiation when the amount of N-TiO2 was 5 g. The degradation ratio was increased from 25.5 to 59.6% when the illumination intensity of the visible light was increased from 0 to 30,000 lux. However, the degradation ratio could not be further increased by further increasing the illumination intensity.
    Research on Chemical Intermediates 03/2009; 35(3):313-320. DOI:10.1007/s11164-009-0026-8 · 1.54 Impact Factor
  • Jing Ma, Yi Wei, Wen-Xiu Liu, Wen-Bin Cao
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    ABSTRACT: Nanocrystalline Fe-doped TiO2 powders were prepared using TiOSO4, urea, and Fe(NO3)3 · 9H2O as precursors through a hydrothermal method. The as-synthesized yellowish-colored powders are composed of anatase TiO2, identified by X-ray diffraction (XRD). The grain size ranged from 9.7 to 12.1 nm, calculated by Scherrer’s method. The specific surface area ranged from 141 to 170 m2/g, obtained by the Brunauer–Emmett–Teller (BET) method. The transmission electron microscopy (TEM) micrograph of the sample shows that the diameter of the grains is uniformly distributed at about 10 nm, which is consistent with that calculated by Scherrer’s method. Fe3+ and Fe2+ have been detected on the surface of TiO2 powders by X-ray photoelectron spectroscopy (XPS). The UV–Vis diffuse reflection spectra indicate that the light absorption thresholds of the Fe-doped TiO2 powders have been red-shifted into the visible light region. The photocatalytic activity of the Fe-doped TiO2 was evaluated through the degradation of methylene blue (MB) under visible light irradiation. The Fe-doped TiO2 powders have shown good visible-light photocatalytic activities and the maximum degradation ratio is achieved within 4.5 h.
    Research on Chemical Intermediates 03/2009; 35(3):329-336. DOI:10.1007/s11164-009-0027-7 · 1.54 Impact Factor
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    ABSTRACT: (Fe, N) co-doped titanium dioxide powders have been prepared by a quick, low-temperature hydrothermal method using TiOSO4, CO(NH2)2, Fe(NO3)3, and CN3H5·HCl as starting materials. The synthesized powders were characterized by XRD, TEM, BET, XPS, and UV–Vis spectroscopy. Experimental results show that the as-synthesized TiO2 powders are present as the anatase phase and that the N and Fe ions have been doped into the TiO2 lattice. The specific surface area of the powders is 167.8m2/g by the BET method and the mean grain size is about 11nm, calculated by Scherrer’s formula. UV–Vis absorption spectra show that the edge of the photon absorption has been red-shifted up to 605nm. The doped titanium dioxide powders had excellent photocatalytic activity during the process of photo-degradation of formaldehyde and some TVOC gases under visible light irradiation.
    Research on Chemical Intermediates 03/2009; 35(3):321-328. DOI:10.1007/s11164-009-0025-9 · 1.54 Impact Factor