Міжнародна наукова конференція "Архівознавство як наука"

Проаналізовано внесок істориків і архівістів України в розвиток архівної науки. Вказуються основні розділи архівознавства як науки, що вимагають подальших досліджень.Проанализирован вклад историков и архивистов Украины в развитие архивной науки. Указываются основные разделы архивоведения как науки, которые требуют дальнейших исследований.A contribution of Ukrainian historians and archivists to the archival science development is covered. The basic sections of the archival science which need the further study are indicated

Synthesis and characterization of Au/Ti-SBA-15 catalysts for the vapour phase epoxidation of propylene

Au-Ti-SBA-15 catalysts have been synthesized using different preparation routes. Ti-SBA-15 supports with Si/Ti ratio ranging from 10 to 80 have been prepared by grafting and direct synthesis. X-ray fluorescence (XRF), X-ray diffraction (XRD), diffuse reflectance UV-visible spectroscopy (DRS), transmission electron microscopy (TEM) and nitrogen sorption were applied for the characterization of the prepared catalysts. The catalytic activities of the Au/Ti-SBA-15 materials have been investigated in the direct epoxidation of propene by using a mixture of H2 and O2 and its performance was compared with an Au/TiO2 catalyst. The activity results were then interpreted with reference to the characterization

A transient kinetic analysis of the epoxidation of propene over gold-titania catalysts

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Imaging the effect of a hydrothermal treatment on the pore accessibility and acidity of large ZSM-5 zeolite crystals by selective staining

Confocal fluorescence microscopy has been used in combination with bulky non-reactive dyes (i.e. proflavine, stilbene and nile blue A) and two staining reactions (i.e. fluorescein synthesis and 4-fluorostyrene oligomerisation) to study the effect of steaming on pore accessibility and acidity of large ZSM-5 zeolite crystals. This approach enabled the 3-D visualization of cracks and mesopores connected to the outer zeolite surface as well as mesoporous cavities within steamed ZSM-5 zeolite crystals. It has been found that besides the generation of mesoporosity steaming makes the boundaries between the different crystal sub-units accessible for bulky molecules. Additionally, the fluorescein staining reaction reveals prominent formation of structural defects that are connected to the surface of the crystal via the microporous ZSM-5 system and which contain either Brønsted or Lewis acid sites. On the other hand, the 4-fluorostyrene staining reaction shows how mild steaming conditions increase the accessibility towards the Brønsted acid sites, while under severe steaming conditions the Brønsted acidity contained in the internal crystal sub-units is more accessible, although it is preferentially removed close to the surface of the lateral sub-units of ZSM-5 zeolite crystals

Efficient and highly transparent ultra-thin nickel-iron oxy-hydroxide catalyst for Oxygen evolution prepared by successive Ionic layer adsorption and reaction

NiFeOx thin films prepared by successive ionic layer adsorption and reaction (SILAR) were deposited onto nanostructured hematite (Fe2O3) photoanodes and their effect on the current density and photo‐onset potential was studied. After optimization of bath concentration, immersion times, and number of SILAR cycles, very conformal and active NiFeOx films with controlled Fe/Ni content ratios were obtained. Upon the incorporation of Fe2+ species in the NiCl2 solution bath, a cathodic shift in the overpotential required for the oxygen evolution reaction (OER) by more than 200 mV with no decrease in current density was observed after 40 SILAR cycles. We demonstrate that by fine‐tuning the film composition and thickness, NiFeOx can be employed as an efficient OER catalyst with very low absorbance in the visible spectrum. By doing so, we demonstrate that this material has great potential for incorporation in semiconductor photoelectrodes for direct solar‐driven water electrolysis. Being a simple water‐based layer‐by‐layer growth method, SILAR offers promise for the synthesis of catalyst coatings in nano‐structured and high surface area electrodes

Stability of Pt/γ-Al2O3 catalysts in lignin and lignin model compound solutions under liquid phase reforming reaction conditions

The stability of a 1 wt % Pt/¿-Al2O3 catalyst was tested in an ethanol/water mixture at 225 °C and autogenic pressure, conditions at which it is possible to dissolve and depolymerize various kinds of lignin, and structural changes to the catalysts were studied by means of X-ray diffraction (XRD), 27Al MAS NMR, N2 physisorption, transmission electron microscopy (TEM), H2 chemisorption, elemental analysis, thermogravimetric analysis-mass spectrometry (TGA-MS), and IR. In the absence of reactants the alumina support is found to transform into boehmite within 4 h, leading to a reduction in support surface area, sintering of the supported Pt nanoparticles, and a reduction of active metal surface area. Addition of aromatic oxygenates to mimic the compounds typically obtained by lignin depolymerization leads to a slower transformation of the support oxide. These compounds, however, were not able to slow down the decrease in dispersion of the Pt nanoparticles. Vanillin and guaiacol stabilize the aluminum oxide more than phenol, anisole, and benzaldehyde because of the larger number of oxygen functionalities that can interact with the alumina. Interestingly, catalyst samples treated in the presence of lignin showed almost no formation of boehmite, no reduction in support or active metal surface area, and no Pt nanoparticle sintering. Furthermore, in the absence of lignin-derived aromatic oxygenates, ethanol forms a coke-like layer on the catalyst, while oxygenates prevent this by adsorption on the support by coordination via the oxygen functionalities