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Preparation, characterization and photocatalytic activity of Co3O4/LiNbO3 composite

100%
Zielinska B., Janus M., Kalenczuk R.
Open Chemistry
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2013
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vol. 11
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issue 6
920-926
EN
The Co3O4/LiNbO3 composites were synthesized by impregnation of LiNbO3 in an aqueous solution of cobalt nitrate and next by calcination at 400°C. The activity of produced samples has been investigated in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were studied using X-ray diffraction (XRD), diffuse reflectance (DR) UV-vis and resonance Raman spectroscopic techniques, respectively. The influence of cobalt content (range from 0.5 wt.% to 4 wt.%) on the photocatalytic activity of Co3O4/LiNbO3 composites for photocatalytic hydrogen generation has been investigated. Co3O4/LiNbO3 composites exhibited higher than LiNbO3 photocatalytic activity for hydrogen generation. The highest H2 evolution efficiency was observed for Co3O4/LiNbO3 composite with 3 wt.% cobalt content. The amount of H2 obtained in the presence of LiNbO3 and Co3O4/LiNbO3 (3 wt.% of cobalt content) was 1.38 µmol/min and 2.59 µmol min−1, respectively. [...]
2
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Dye decomposition on P25 with enhanced adsorptivity

100%
Janus M., Wawrzyniak B., Tryba B., Morawski A.
Polish Journal of Chemical Technology
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2008
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vol. 10
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issue 2
11-16
EN
The preparation method and the activity of the TiO2-P25/N doped photocatalyst based on commercial titanium dioxide (TiO2 Aeroxide® P-25 Degussa, Germany) are presented. For the TiO2-P25/N preparation TiO2-P25 and gaseous ammonia were kept in a pressure reactor (10 bars) for 4 hours at the temperature of 200°C. This modification process changed the chemical structure of the TiO2 surface. The formation of NH4+ groups was confirmed by the FTIR measurements. Two bands in the range of ca. 1430 - 1440 cm-1 attributed to bending vibrations of NH4+ could be observed on the FTIR spectra of the catalysts modified with ammonia and the band attributed to the hydroxyl groups at 3300 - 3500 cm-1, which were not reduced after N-doping. The photocatalytic activity of the photocatalysts was checked through the decomposition of two dyes under visible light irradiation. The modified TiO2 thus prepared samples were more active than TiO2-P25 for the decomposition of dyes under visible light irradiation.
3
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Preparation of the TiO2photocatalyst using pressurized ammonia

100%
Wawrzyniak B., Janus M., Grzmil B., Morawski A.
Polish Journal of Chemical Technology
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2007
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vol. 9
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issue 1
51-56
EN
The industrial hydrated amorphous titanium dioxide (TiO2ċ xH2O) was modified by treatment inside a chemical reactor under elevated pressure at low temperatures for 4 hours in an ammonia atmosphere. On the basis of the FTIR/DRS analysis the presence of nitrogen was confirmed. The XRD patterns of all of the catalysts exhibit mainly the diffraction lines of anatase phases. The photocatalytic activity of the modified photocatalysts was determined and compared to TiO2-P25 (Degussa, Germany). The high rate of phenol and dye degradation was obtained for the catalysts modified at 180°/15atm. TiO2-P25 showed similar activity in phenol decomposition like TiO2-15bar, whereas it was more active in dye decomposition.
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TiO2modified by ammonia as a long lifetime photocatalyst for dyes decomposition

88%
Choina J., Dolat D., Kusiak E., Janus M., Morawski A.
Polish Journal of Chemical Technology
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2009
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vol. 11
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issue 4
1-6
EN
Ammonia-modified TiO2 (TiO2/N), prepared in a pressure reactor was used as the well- active and longlife photocatalyst for the azo dye (Reactive Red 198) decomposition. The effect of aeration and the different value of the pH of the reaction medium on the photocatalytic degradation of Reactive Red 198 in water has been investigated. It has been reported that the degradation is greatly influenced by the reaction pH and the faster decomposition of azo dye took place at pH 3.5. When the solution was acidic, a larger amount of azo dye on the positively charged surface of TiO2 photocatalysts was adsorbed. From the obtained results it can be seen that the effectiveness of the decolourisation of the solution was faster by using the nitrogen-modified TiO2.
5
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Photocatalytic properties of nanocrystalline TiO2 thin films doped with Tb

76%
Wojcieszak D., Kaczmarek D., Domaradzki J., Prociow E., Morawski A., Janus M.
Open Physics
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2011
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vol. 9
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issue 2
354-359
EN
In this work photocatalytic properties of TiO2 thin films doped with different amount of Tb have been described. Thin films were prepared by high energy reactive magnetron sputtering process. Comparable photocatalytic activity has been found for all doped TiO2 thin films, while different amounts of Tb dopant (0.4 and 2.6 at. %) results in either an anatase or rutile structure. It was found that the terbium dopant incorporated into TiO2 was also responsible for the amount of hydroxyl groups and water particles adsorbed on the thin film surfaces and thus photocatalytic activity was few times higher in comparison with results collected for undoped TiO2 thin films.
6
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NOx photocatalytic degradation on gypsum plates modified by TiO2-N,C photocatalysts

76%
Janus M., Bubacz K., Zatorska J., Kusiak-Nejman E., Czyżewski A., Morawski A. W.
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EN
In presented studies the photocatalytic decomposition of NOx on gypsum plates modified by TiO2-N,Cphotocatalysts were presented. The gypsum plates were obtained by addition of 10 or 20 wt.% of different types of titanium dioxide, such as: pure TiO2 and carbon and nitrogen co-modified TiO2 (TiO2-N,C) to gypsum. TiO2-N,C photocatalysts were obtained by heating up the starting TiO2 (Grupa Azoty Zakłady Chemiczne Police S.A) in the atmosphere of ammonia and carbon at the temperature: 100, 300 i 600ºC. Photocatalyst were characterized by FTIR/DRS, UVVis/DR, BET and XRD methods. Moreover the compressive strength tests of modified gypsum were also done. Photocatalytic activity of gypsum plates was done during NOx decomposition. The highest photocatalytic activity has gypsum with 20 wt.% addition of TiO2-N,C obtained at 300ºC.
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Preliminary studies of photocatalytic activity of gypsum plasters containing TiO2co-modified with nitrogen and carbon

76%
Janus M., Bubacz K., Zatorska J., Kusiak-Nejman E., Czyżewski A., Morawski A. W.
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EN
The conducted studies were focused on the development of the gypsum material exhibiting self-cleaning properties. To this end, the raw gypsum was mixed with unique TiO2-based photocatalysts, previously modified by nitrogen and/ or carbon doping. The photocatalytic activity of the obtained gypsum plasters was evaluated trough the degradation of model organic compound (Reactive Red 198) under UV-vis irradiation. The impact of the photocatalysts presence on the physicochemical properties of the obtained gypsum plasters was evaluated. Furthermore, the role of non-metals presence on the photocatalytic properties of the TiO2 was determined. It was confirmed that the addition of N,C co-modified titanium dioxide into gypsum bestows this material with self-cleaning properties. The highest dye removal rate was displayed by the gypsum plaster containing optimal amount (10 wt%) of co-modified TiO2/N,C photocatalyst, after 20 hours of UV-vis irradiation.
8
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Carbon modified TiO2photocatalysts for water purification

76%
Morawski A., Janus M., Tryba B., Toyoda M., Tsumura T., Inagaki M.
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EN
Carbon can form different structures with TiO2: carbon-doped TiO2, carbon coated TiO2 and composites of TiO2 and carbon. The presence of carbon layer on the surface of TiO2 as well as the presence of porous carbon in the composites with TiO2 can increase the concentration of organic pollutants on the surface of TiO2, facilitating the contact of the reactive species with the organic molecules. Carbon-doped TiO2 can extend the absorption of the light to the visible region by the narrowing of the band gap and makes the photocatalysts active under visible light irradiation. TiO2 loaded carbon can also work as a photocatalyst, on which the molecules are adsorbed in the pores of carbon and then they undergo the photocatalytic decomposition with UV irradiation. Enhanced photocatalytic activity for the destruction of some organic compounds in water was noticed on the carbon coated TiO2 and TiO2 loaded activated carbon, mostly because of the adsorptive role of carbon. However, in carbon-doped TiO2, the role of carbon is somewhat different, the replacement of carbon atom with Ti or oxygen and formation of oxygen vacancies are responsible for extending its photocatalytic activity towards the visible range.
9
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Photocatalytic properties of transparent TiO2 coatings doped with neodymium

64%
Wojcieszak D., Kaczmarek D., Domaradzki J., Mazur M., Morawski A. W., Janus M., Prociów E., Gemmellaro P.
Polish Journal of Chemical Technology
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2012
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vol. 14
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issue 3
1-7
EN
In this work photocatalytic properties of TiO2 thin fi lms doped with 8.51 at. % of Nd were described. The self-cleaning phenomenon of thin fi lms was discussed together with the structural, optical and surface properties of prepared thin fi lms. Transparent coatings based on titanium dioxide were manufactured by high-energy reactive magnetron sputtering process. Incorporation of Nd during sputtering process results in amorphous behavior, without a signifi cant infl uence on transparency and colour as compared to the undoped TiO2-rutile matrix. Nevertheless, doping with neodymium doubles the photocatalytic activity of the matrix due to higher quantity of photo-generated charge carriers and more effi cient mechanism of energy transfer.
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