In this work, the effect of Pd addition on nanostructured TiO2 powders is studied. The materials were obtained by the sol-gel method and characterized by XRD, Rietveld refinement, TEM, Raman and UV-vis spectroscopies. The crystal structure and the nature of the different TiO2 phases were modified by varying the palladium/TiO2 ratio: 0.01, 0.03, and 0.05. The XRD results revealed the presence of different combinations of TiO2 (B), anatase, rutile and PdO phases as well as their coexistence in the different samples. The Rietveld analysis showed that the composition of the phases is rather affected by the amount of Pd added to the TiO2 structure. The Raman spectroscopy confirmed the characteristic bands of the TiO2 phases in the samples and their variation depending on the Pd/TiO2 ratio. The TEM results indicated that the as-prepared samples displayed crystal sizes of nanometric order (˂ 80nm). The observed reduction of the band gap was also correlated with the combination of phases due to the palladium addition. All the Pd/TiO2 samples showed a significant improvement in the elimination of 4-chlorophenol during the application of water treatment technology.

The use of silane formulations for the pre-treatment of metallic substrates prior to painting or as topcoat has been increasing during the recent years. The proposed formulations are very attractive because they present environmental friendliness, enhance adhesion properties and provide a barrier layer that delays the corrosion processes. One of the most used techniques to synthesized based-SiO 2 coatings is solgel. The preparation of sol-gel coatings with specific chemical functions offers potential advantages over traditional methods as it offers tailoring of their structure, texture and thickness and allows the fabrication of large coatings. The present work investigates the electrochemical behaviour of commercial carbon steel coated with ceria doped SiO 2 by sol-gel process in basic media. To evaluate the influence of temperature on adhesion and protective properties, the coatings were sintered at three different temperatures, 623 K, 723 K and 873 K, for 3 h. The anticorrosion behaviour, of the films has been characterized in an aggressive medium by electrochemical techniques, while structural characteristics and morphology was followed by X-Ray Diffraction, Fourier Transformed Infra-Red and Scanning Electron Microscopy techniques. The results indicated that the thin films act as a protective barrier against exposure to the corrosive medium (3.5 wt-% NaCl solution) and increase the lifetime of the susbtrate.

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