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Abstract: Nanocomposites based on TiO2 aerogel and Ag nanoparticles have been successfully obtained through different synthesis methods and their specific surface areas have been determined by N2 sorption (BET method). The photocatalytic potential for salicylic acid degradation has been evaluated. It was found that under visible light irradiation, all synthesized nanocomposites exhibit higher photocatalytic activity than the commercially available Aeroxide P25. By correlating the structural parameters with the photocatalytic performances, it has been found that the Ag nanoparticles and brookite phase presence alongside the anatase play important roles on the visible photocatalysts behavior. For the Ag containing samples with mixed anatase–brookite phases, it has been observed that the visible photocatalytic performance decreases with the increase in brookite crystalline phase content. On the other hand, the addition of Ag nanoparticles results, as expected, in a clear enhancement of the visible photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Ba(Zn1/3Ta2/3)O3 (BZT) thin films were grown on Pt-coated Si substrates at 500°C substrate temperatures by pulsed electron beam deposition method and post-annealed at 600 and 650°C for 1h. The X-ray diffraction patterns indicate that the as-grown films are partially crystallized but single-phase cubic perovskite structure was formed in annealed films. The temperature dependence of the dielectric constant of the BZT films was recorded in the −100 to +100°C range. The annealing treatment induces a decrease of the temperature coefficient of the dielectric permittivity with an order of magnitude, from 2000 to 100ppm/°C. The influence of the annealing treatments on the temperature behavior of the BZT films was evidenced; a dielectric constant of about 21 at room temperature was obtained for the films annealed at 650°C. [Copyright &y& Elsevier]

Abstract: Iron- and europium-doped (≤1at.%) TiO2 nanoparticles powders have been synthesized by a hydrothermal route at 200°C, starting with TiCl4, FeCl3·6H2O and EuCl3·6H2O. The structure, morphology and optical peculiarities were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), extended X-ray absorption fine structure (EXAFS), Mössbauer spectroscopy and UV–vis measurements. The photocatalytic performance was analysed in the photodegradation reaction of phenol. Rietveld refinements of XRD patterns reveal that the as-prepared samples consist in iron- and europium-doped TiO2 in the tetragonal anatase structural shape, with particle size as low as 15nm. By means of Mössbauer spectroscopy on both 57Fe and 151Eu isotopes as well as by EXAFS analyses, the presence of Fe3+ and/or Eu3+ ions in the nanosized powders has been evidenced. It was found that iron and europium ions can substitute for titanium in the anatase structure. From the UV–vis reflection spectra, by using the transformed Kubelka–Munk functions, the band gap energy (E g) of the hydrothermal samples has been determined in comparison with that of Degussa P-25 photocatalyst. A decrease of E g from 2.9eV found for Degussa photocatalyst to 2.8eV for the titania doped with 1at.% Fe has been evidenced, indicating a valuable absorption shift (∼20nm) towards visible light region. However, the best photocatalytic activity in the photodegradation reaction of phenol was evidenced for the hydrothermal sample, TiO2: 1at.% Fe, 0.5at.% Eu, in both UV and visible light regions. The photocatalytic activities of iron-doped and iron–europium-codoped samples are high and practically the same only in visible light. The photocatalytic properties in correlation with the structural and optical peculiarities of the hydrothermal samples are discussed. [Copyright &y& Elsevier]

The Kα1,2 emission lines in 3d transition elements were investigated using a high-resolution anti-parallel crystal spectrometer. A double Lorentzian model of the Kα X-ray emission spectra in these elements has been proved to be able to fit the experimental curve of the diffracted intensity like the case on Cu. Their energy positions, full-width at half-maximum (FWHM), and intensity ratio were obtained by Lorentzian fitting method for these diagram lines. Moreover, the contribution of the 3d spectator hole is experimentally and theoretically confirmed in the Zn Kα 1,2 spectra using GRASP2 code for a convenience of the calculation. [Copyright &y& Elsevier]

Abstract: A sandwich structure of four double layers of Ag (5nm)/As2S3 (82.7nm) has been prepared by Pulsed Laser Deposition (PLD) method. The effect of broadband light on the multilayer structure has been investigated. The X-ray reflectivity (XRR) patterns after different irradiation times have been measured. Although the fully intermixing of Ag and As2S3 layers should be expected during irradiation with visible light, however even after 5h of irradiation the intermixing is not completed. The characteristic features of XRR diagrams for long irradiation times have been interpreted by scattering of X-ray radiation on clusters of Ag or Ag–As2S3. [Copyright &y& Elsevier]