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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

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

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.

4

Wytwarzanie i właściwości nanoproszku Al2O3 domieszkowanego metalami ziem rzadkich

Polis P., Jastrzębska A., Kuś M., Piramidowicz R., Kunicki A., Olszyna A.

Materiały Ceramiczne

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2011

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T. 63, nr 2

419-423

PL

Dyskutowana jest nowatorska metoda wytwarzania nanotlenku glinu domieszkowanego metalami ziem rzadkich. Organiczny prekursor otrzymywano w łagodnej reakcji związków glinoorganicznych z tlenem z powietrza. Kolejnym etapem było wprowadzenie dodatku związku lantanowca i kalcynacja, prowadzące do otrzymania nanoproszku Al2O3/Ln. Metodą tą otrzymano nanoproszki Al2O3 domieszkowane iterbem, prazeodymem, holmem i tulem, charakteryzujące się średnią wielkością cząstki w zakresie 40-96 nm oraz średnią wielkością aglomeratu w zakresie 1,9-42,94 μm. Otrzymane wyniki pokazują, że warunki syntezy organicznego prekursora oraz dodatek metalu ziem rzadkich, mają istotny wpływ na morfologię i właściwości fizyczne nanoproszków Al2O3/Ln. Nanoproszki posiadały znacznie rozwiniętą powierzchnię właściwą (ponad 370 m2/g), a także wysoką wartość porowatości otwartej, która świadczy o nieznacznej tendencji do aglomeracji i luźnej strukturze ewentualnie powstałych aglomeratów. Nanoproszki charakteryzowały się również zadowalającymi parametrami optycznymi.

EN

An innovatory method for producing nanoalumina with rare earth metal addition is discussed. Organic precursor has been obtained by the mild reaction of aluminum metalorganic compounds with oxygen provided by air. In the next stage, the precursor was doped with a lanthanide compound and calcined to obtain Al2O3/Ln nanopowder. Using this method, the Al2O3 nanopowders doped with ytterbium, praseodymium, holmium and thulium have been obtained, that showed average particle and agglomerate sizes of 40-96 nm and 1.9 to 42.94 μm, respectively. The obtained results indicate that conditions of the organic precursor synthesis and the addition of rare earth metal have a significant effect on the morphology and physical properties of the Al2O3/Ln nanopowders. The nanopowders had significantly developed surface areas (over 370 m2/g-1) and also a high open porosity value, evidencing the only slight tendency to agglomeration and a loose structure of the possible agglomerates. The nanopowders showed also satisfactory optical parameters.