Yanfeng Zhang

Publications (3)2.83 Total impact

• Article: Inhibition effect of phosphate on the crystal grain growth of nanosized titania

  Xiaohui Feng, Jingze Liu, Ping Li, Yanfeng Zhang, Yu Wei
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  ABSTRACT: The inhibitory effect of phosphate on the crystal grain growth of nanosized titania during high temperature calcination was investigated. Nanosized titanium dioxide powders prepared by hydrolysis of titanium tetrachloride were soaked in phosphate solutions with different concentrations. The obtained powders calcined at various temperatures were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectronic spectroscopy (XPS). The grain size of the samples without phosphate treatment increased quickly when calcined at high temperatures, while the grain size of the samples with phosphate modification increased slowly when calcined at the same temperature. This phenomenon implies that phosphate treatment plays an important role in inhibiting the crystal grain growth of titania. The possible mechanism of the inhibition effect of phosphate on titania is discussed.
  Rare Metals 04/2012; 28(4):385-390. · 0.59 Impact Factor
• Article: Simple fabrication and photocatalytic activity of S-doped TiO2 under low power LED visible light irradiation

  Yanmin Liu, Jingze Liu, Yulong Lin, Yanfeng Zhang, Yu Wei
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  ABSTRACT: A series of S-doped TiO2 with visible-light photocatalytic activity were prepared by a simple hydrolysis method using titanium tetrachloride (TiCl4) and sodium sulfate (Na2SO4) as precursors. The photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV–vis diffuse reflectance spectrophotometer (UV–Vis DRS), and X-ray photoelectron spectroscopy (XPS). With the doping of S, photocatalysts with small crystal size, high content of anatase phase were obtained. The result showed that S-doped TiO2 demonstrate considerably high photoactivity under low power visible LED light irradiation, while undoped TiO2 and the Degussa P25 have nearly no activity at all. The possible mechanism of S-doped for the visible-light activity was discussed.
  Ceramics International. 35(8):3061-3065.
• Article: Catalytic synthesis of nanosized hematite particles in solution

  Hui Liu, Yu Wei, Ping Li, Yanfeng Zhang, Yuhan Sun
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  ABSTRACT: Spherical hematite particles have been quickly synthesized by heating Fe(OH)3 gel with trace Fe(II) in aqueous solution to reflux temperature. The final product is characterized by XRD, TEM, HRTEM, and FT-IR techniques. The influence of various factors on the size and morphology of hematite particles is investigated, respectively. The growth mechanism of hematite particles is also discussed. The results show that both the mechanisms, dissolution/reprecipitation and solid state transformation, work alternately in the transformation process from Fe(OH)3 to hematite particles until the transformation is finished. The magnetism of the product is also studied.
  Materials Chemistry and Physics 102(1):1-6. · 2.23 Impact Factor