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1
Content available Pr-doped TiO2. The effect of metal content on photocatalytic activity
Reszczynska J., Arenas Esteban D., Gazda M., Zaleska A.
Physicochemical Problems of Mineral Processing
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2014
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Vol. 50, iss. 2
515--524
EN
Pr-TiO2 nanoparticles were prepared by using a sol-gel method. As-prepared samples were characterized by BET measurements, X-ray powder diffraction analysis (XRD) and UV-Vis spectra. Visible and ultraviolet light photocatalytic activity of the sample was studied by photodegradation of phenol, while considering the influence of the dopant concentration. TiO2 doped with 0.25 mol% of praseodymium showed the highest photocatalytic activity under visible light irradiation. Pr-TiO2 had anatase structure. The surface area was higher for powders with higher content of rare earth metal ion, and ranged from 121 to 150 m2/g. Red shifts of absorption edge toward the visible region were observed for the doped samples compared to pure TiO2.
2
Content available Au-RE-TiO2 nanocomposites. surface characteristics and photoactivity
Krukowska A., Reszczynska J., Zaleska A.
Physicochemical Problems of Mineral Processing
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2014
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Vol. 50, iss. 2
551--561
EN
Photocatalysts based on TiO2 co-doped with rare earth metal (RE) and gold nanoparticles have been prepared using a sol-gel method and followed by gold reduction. Specific surface areas of the modified photocatalysts were calculated by the Brunauer-Emmett-Teller method (BET). Diffuse reflectance spectra of the obtained photocatalysts were recorded with a UV-Vis spectrophotometer (DRS UV-Vis). The influence of the type of rare earth metal on photoactivity of Au-RE-TiO2 nanocomposites in model reaction manifested by toluene photodegradation in a gas phase was investigated. The obtained results showed that photodegradation of toluene in the gas phase is possible over Au-RE-TiO2 irradiated by UV or Vis light. The Au-RE-TiO2 photocatalysts relative to undoped TiO2, did not caused an increase of toluene degradation in the air under visible light. The samples doped with Er3+ or Pr3+ presented the highest activity in solar light among of Au-RE-TiO2. It was observed that both metal dopants affected the surface area of TiO2. The Au-RE-TiO2 photocatalysts relative to undoped TiO2 exhibited the absorption properties under Vis light.
3
Content available remote Preparation and photocatalytic activity of iron- modified titanium dioxide photocatalyst
Lezner M., Grabowska E., Zaleska A.
Physicochemical Problems of Mineral Processing
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2012
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Vol. 48, iss. 1
193-200
EN
Iron modified TiO2 was prepared by the sol-gel method and surface modification method followed by calcination at 400°C. Two types of titanium dioxide: TiO2 ST-01(Ishihara Sangyo Ltd., Japan;300 m2/g), and TiO2 P25 (Evonik, Germany, 50 m2/g) were used in the grinding procedure. The photocatalysts were characterized by UV-VIS absorption and BET surface area measurements. The photocatalytic activity of the obtained powders in UV-Vis and visible light was estimated by measuring the decomposition rate of phenol (0.21 mmol/dm3) in an aqueous solution. The best photoactivity under visible light was observed for iron doped TiO2 with 0.5% by grinding the TiO2 ST-01.
4
Content available remote Characterization And Photocatalytic Activity Of Rare Earth Metal-Doped Titanium Dioxide
Reszczynska J., Iwulska A., Sliwinski G., Zaleska A.
Physicochemical Problems of Mineral Processing
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2012
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Vol. 48, iss. 1
201-208
EN
The aim of this research was to prepare rare metal (Er, Yb)-modified TiO2 nanoparticles by a sol-gel method. The obtained nanoparticles were characterized by BET measurements, UV-Vis spectra and the Laser-induced fluorescence (LIF) method. Visible light photocatalytic activity of the sample was studied by photodegradation of phenol while considering the influence of the dopant concentration. The obtained results showed that a smaller amount of the dopant gave better photocatalytic activity of a semiconductor. The absorption spectra of Yb3+-doped and Er3+-TiO2 samples show stronger absorption in the UV-Vis region than pure TiO2. The presence of erbium was found more beneficial for visible light activation of TiO2 doped photocatalysts than ytterbium.
5
Content available remote Photocatalytic activity of TiO2 loaded with metal clusters
Grabowska E., Remita H., Zaleska A.
Physicochemical Problems of Mineral Processing
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2010
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Vol. 45
29-38
EN
TiO2 was surface modified with silver, gold and platinum ion clusters to improve its photocatalytic activity. The effect of metal content, the kind of dopant and titanium dioxide source (commercial - P25 and ST-01) used during preparation procedure on photoactivity were investigated. The photocatalytic activity was estimated by measuring the decomposition rate of 0.21 mM phenol aqueous solution under UV-Vis and visible (λ > 400 nm). The highest photoactivity was observed for TiO2 loaded with silver (2%Ag on P25), gold (1%Au on P25) and platinum (0.5% Pt on ST-01) clusters. After 60 min. of irradiation under UV light phenol solution was degraded in 91%, 49% and 91%, respectively
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