The hierarchical Zr-MTW zeolites are prepared using NH 4 F and HF as mineralizing agents and structure-directed agent like Gemini-type surfactant and studied by X-ray diffraction (XRD), 29 Si magic angle spinning nuclear magnetic resonance ( 29 Si MAS NMR), Fourier transform infrared (FTIR) spectroscopy with pyridine, 2,6-di-tert-butylpyridine and CD 3 CN as probe molecules. Structural characteristics and acid-base properties of the zeolites depend on concentration of fluorine precursor in the reaction medium (a ratio of Si/F). The hierarchical Zr-MTW zeolites (included doped with copper) have been tested in ethanol conversion into 1,3-butadiene by Lebedev method. The symbatical dependence of 1,3-butadiene productivity with the concentration of Lewis acidic sites determined by FTIR spectroscopy of adsorbed CD 3 CN is observed. 1.3-Butadiene selectivity of 68 % with ethanol conversion of 81 % are achieved in the presence of Cu/Zr-MTW catalyst. [a] M. M. Kurmach, Dr. O. V. Larina, Dr. P. I. Kyriienko, P. S. Yaremov, Dr. O. V. Shvets, Prof. S. O. Soloviev alexshvets@ukr.net [b] Dr.
For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.
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