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Flower-like NiAl-layered double hydroxides (LDH) were successfully synthesized by a straightforward one-pot hydrothermal method using Ni(II) glycinate complex as a chemical precursor under extremely high basic conditions and soft hydrothermal conditions. Systematic screening of synthesis parameters such as reaction time and hydrothermal process temperature was carried out. The materials have been thoroughly characterized via a set of techniques including X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, chemical analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermal gravimetric analysis (TG). The results demonstrate that a too long reaction time value disrupts the flower-like microspheres and a too high temperature value is deleterious for the LDH structure. Transition mixed oxides with the same flowerlike morphology were readily obtained by thermal treatment at a moderate temperature of the above LDH precursors.

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This report describes the first synthesis of a highly crystalline YAG:Tb nanophosphor inside the pores of a mesoporous silica monolith (MSM).

Upon blue excitation, acac-modified solutions present significantly higher luminescence compared to unmodified ones due to the presence of pre-nuclei of YAG:Tb structure which is very interesting for using them for optical applications.

Novel BiOF/TiO2 heterostructures with controlled amounts of BiOF and TiO2 have been successfully synthesized via a simple solid‐state sintering method. The structural, morphological and optical properties were analyzed using several characterization techniques. A shift of the TiO2 absorption edge toward the visible region was observed. The optimal molar ratio of BiOF/TiO2 was found to be (1:3) with a photodegradation percentage of 91.2 % and it was 7 and 5 times more efficient than that of pure BiOF or TiO2 nanopowder, respectively. BiOF/TiO2 (1:3) heterojunction has showed high photodegradation stability for the Rh B photodegradation after three cycles. In the proposed photocatalytic mechanism, TiO2 absorbed the visible light and carried out the photocatalytic reaction owing to the decrease of its band gap value due to the formation of oxygen vacancies, while BiOF played an important role in the charge separation process due to the intimate contact of the BiOF/TiO2 heterojunction.

International audienceThis work focuses on the formation of large, luminescent and transparent thick films of polyvinylpyrrolidone (PVP) embedding phosphors. Characterization of these films was made using UV-Visible absorption spectroscopy and cw-selective excitation induced photoluminescence. Results presented here demonstrate the preparation polymer films incorporating luminescent materials in order to obtain large, transparent and thick surfaces of well-dispersed phosphors suitable for use in optical devices. This technique allows the preparation of self-standing, flexible and handy films that could be easily cut or shaped and then used for various purposes