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I presupposti e il procedimento di adozione delle ordinanze ex art. 54 TUEL
No full textIl capitolo analizza i presupposti per l'emanazione delle ordinanze sindacali e, specificamente, delle ordinanze sindacali ex art. 54 TUEL e il loro procedimento di adozione
Hydrothermal synthesis of high surface LiFePO4 powders as cathode for Li-ion cells
No full textAn easy, quick and low cost hydrothermal synthesis was developed to prepare high surface area phospho-olivine LiFePO4 powders to be used as cathodematerial for Li-ion batteries. The samples were prepared in double distilled water starting fromcommercial LiOH, FeSO4,H3PO4 and using solutionswith different concentrations of a surfactant compound (CTAB), in order to increase the specific surface areas, obtaining powderswith very small grain size. The structural, morphological and electrochemical properties were investigated by means of X-ray powder diffraction (XRPD), ICP-AES, BET method, scanning electron microscopy (SEM) and constant current charge-discharge cycling. The electrochemical performances of LiFePO4 prepared in this manner showed to be positively affected by the presence of CTAB during synthesis, showing capacities near the theoretical value, only slightly affected by the discharge regime (from C/20 to 10C
ACIDIC PROPERTIES OF TITANIUM-SILICALITES-1
No full textDifferent titanium silicalites-1(TS-1), synthesized following two different routes in the presence or in the absence of sodium in the precursor gel have been characterized by adsorption of ammonia. Adsorption calorimetric measurements of a basic probe(NH3) and an acidic probe(SO2) have shown that these solids were very acidic compared to a silicalite-1 sample. The presence of Na in the different samples decreases the number and the strength of the acid sites. The modification strongly depends on the synthesis procedure
Hydrothermal synthesis and characterization of high performance LiFePO4 powders as cathode for Li-ion cells
No full textI presupposti e il procedimento di adozione delle ordinanze ex art. 54 TUEL
No full textIl capitolo analizza i presupposti per l'emanazione delle ordinanze sindacali e, specificamente, delle ordinanze sindacali ex art. 54 TUEL e il loro procedimento di adozione
About the role of a surfactant leading to a high performance nanostructured LiFePO4/C cathode
No full textSynthesis of encapsulated nanoparticules in hollow beta zeolite
No full textSSCI-VIDE+ING+AMP:ATU:DFAInternational audienceHollow Zeolites with encapsulated nanoparticles (NPs) have recently attracted much attention due to their remarkable advantages as catalytic nanoreactors compared to bulk zeolite supports. Although zeolite shells provide protection against sintering and poisoning, they are usually polycrystalline, fragile and relatively thick. Recently, we succeeded to prepare a series of metal NPs in single hollow zeolite crystals with MFI-type structure by selective dissolution of bulk crystals preliminary loaded with metal precursors (1). The MFI nano-boxes showed remarkable size selectivity in the hydrogenation of toluene but their activity is limited to small substrates because of the small pore opening of the framework (approx.. 0.55 nm) (2). So far, all examples of NPs in hollow single crystals deal with zeolites of MFI-type structure (ZSM-5 and Silicalite-1).In the present work, we report for the first time the preparation of hollow beta zeolite single crystals containing platinum nanoparticles. Beta nano-boxes are prepared by dissolution/recrystallization of CIT-6 crystals, which is a zincosilicate exhibiting the same *BEA structure, based on a modified method (3).Depending on the preparation method, Pt NPs can be located either (i) on the external surface, (ii) in the walls or (iii) inside the cavity of the crystals (4, 5). Materials have been characterized by X-ray diffraction, N2 adsorption and electron microscopy (TEM and SEM). High resolution tomography has also been used to confirm the location of Pt NPs as well as their narrow particle size distribution. Besides structural characterization, the presentation will illustrate the potential of such materials in catalysis by model reactions such as the hydrogenation of substituted aromatics with different sizes. Catalytic results will be discussed in light of adsorption and diffusion studies.(1) S. Li, A. Tuel, J.-L. Rousset, F. Morfin, M. Aouine, L. Burel, F. Meunier, D. Farrusseng, ChemNanoMat. 2(6) (2016) 534.(2) S. Li, A. Tuel, D. Laprune, F. Meunier, D. Farrusseng, Chem. Mater. 27 (2015) 276.(3) K. Iyoki, K. Itabashi, T. Okubo, Chem. Asian J. 2013, 8, 1419.(4) A. R. Morgado Prates, A. Tuel, D. Farrusseng, N. Bats, Fr. Pat. 16/62.460 (2016).(5) A. R. Morgado Prates, A. Tuel, D. Farrusseng, N. Bats, Fr. Pat. 16/62.461 (2016)
Synthesis of encapsulated nanoparticules in hollow beta zeolite
No full textSSCI-VIDE+ING+AMP:ATU:DFAInternational audienceHollow Zeolites with encapsulated nanoparticles (NPs) have recently attracted much attention due to their remarkable advantages as catalytic nanoreactors compared to bulk zeolite supports. Although zeolite shells provide protection against sintering and poisoning, they are usually polycrystalline, fragile and relatively thick. Recently, we succeeded to prepare a series of metal NPs in single hollow zeolite crystals with MFI-type structure by selective dissolution of bulk crystals preliminary loaded with metal precursors (1). The MFI nano-boxes showed remarkable size selectivity in the hydrogenation of toluene but their activity is limited to small substrates because of the small pore opening of the framework (approx.. 0.55 nm) (2). So far, all examples of NPs in hollow single crystals deal with zeolites of MFI-type structure (ZSM-5 and Silicalite-1).In the present work, we report for the first time the preparation of hollow beta zeolite single crystals containing platinum nanoparticles. Beta nano-boxes are prepared by dissolution/recrystallization of CIT-6 crystals, which is a zincosilicate exhibiting the same *BEA structure, based on a modified method (3).Depending on the preparation method, Pt NPs can be located either (i) on the external surface, (ii) in the walls or (iii) inside the cavity of the crystals (4, 5). Materials have been characterized by X-ray diffraction, N2 adsorption and electron microscopy (TEM and SEM). High resolution tomography has also been used to confirm the location of Pt NPs as well as their narrow particle size distribution. Besides structural characterization, the presentation will illustrate the potential of such materials in catalysis by model reactions such as the hydrogenation of substituted aromatics with different sizes. Catalytic results will be discussed in light of adsorption and diffusion studies.(1) S. Li, A. Tuel, J.-L. Rousset, F. Morfin, M. Aouine, L. Burel, F. Meunier, D. Farrusseng, ChemNanoMat. 2(6) (2016) 534.(2) S. Li, A. Tuel, D. Laprune, F. Meunier, D. Farrusseng, Chem. Mater. 27 (2015) 276.(3) K. Iyoki, K. Itabashi, T. Okubo, Chem. Asian J. 2013, 8, 1419.(4) A. R. Morgado Prates, A. Tuel, D. Farrusseng, N. Bats, Fr. Pat. 16/62.460 (2016).(5) A. R. Morgado Prates, A. Tuel, D. Farrusseng, N. Bats, Fr. Pat. 16/62.461 (2016)
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