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• Si-based bioactive glass coatings fabricated by coupling sol-gel and electrospray. • Compositional optimization of S85, S75, and S58 coatings on Ti6Al4V substrate. • Microstructural tunning of homogeneous BG coatings as a function of ESD parameters. • From very porous coral-type coating morphology to a more compacted cauliflower one. • In-vitro investigation after 24 h immersion in simulated body fluid. For the first time, the sol-gel method was coupled with electrostatic spray deposition (ESD) to fabricate nanotextured bioactive glass (BG) coatings with a controlled microstructure in a one-pot-process. Three BG compositions belonging to the SiO 2 -CaO-P 2 O 5 system (S85, S75, and S58) were homogeneously deposited on metallic Ti6Al4V substrates starting from the atomization of precursor solutions. All coatings displayed an amorphous character, as confirmed by XRD. A wide variety of innovative BG morphologies were obtained, tuning the key parameters of ESD, leading from highly porous coral-like to compact reticular-type coatings. The bioactivity, in terms of apatite formation, of as-deposited coatings was tested by immersion in simulated body fluid solution. Textural properties were found to play an important impact in its biological performance. Highly porous ESD-coatings exhibited remarkable bioactivity for S75 and S58 compositions, compared with more compacted ones of equal formulations. S85 composition was found extremely reactive regardless of the coating microstructure. [ABSTRACT FROM AUTHOR]

In this paper, we report that the hydrogenolysis of glycerol can be carried out at atmospheric pressure and low temperature with high selectivity to 1,2-propanediol (1,2-PDO) over reduced copper catalyst. The vapor-phase reaction was carried out over the copper-based catalysts supported on alumina at ambient pressure, and the effects of temperature, space time, and H2 molar fraction in the feed were analyzed. The textural and structural characteristics of the catalysts with increasing copper loading were determined by N2 sorptometry (BET), inductively coupled plasma-atomic spectroscopy (ICP-AES), powder X-ray diffraction (PXRD), temperature-programmed reduction (TPR), and N2O chemisorption (metallic area). On the basis of both characterization and activity results, it was possible to conclude that the hydrogenolysis of glycerol to 1,2-propanediol in vapor phase at atmospheric pressure over copper-based catalysts is a structure sensitive reaction. Activity results suggests that the most probable pathway for the glycerol conversion into 1,2-propanediol under the employed conditions is glycerol is dehydration to hydroxyacetone (acetol), followed by its hydrogenation into 1,2-propanediol. Complete glycerol conversion and a selectivity of 60% to 1,2-propanediol was achieved, using a catalyst with 15 wt % CuO at 200 °C, H2 molar fraction of 61%, and atmospheric pressure. [ABSTRACT FROM AUTHOR]

The aim of the present work is to analyse the effect of the Ni(II) content for the Ni(II)-Mg(II)/γ-Al 2 O 3 catalysts on the textural and structural characteristics of the solid, as well on the catalytic activity and selectivity to H 2 for the steam reforming of glycerol at atmospheric pressure. The samples with different contents of Ni(II) were characterized by different techniques including: N 2 sorptometry, PXRD, H 2 chemisorption, elemental analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and temperature programmed reduction (TPR). The catalytic activity of the samples was tested in the steam reforming of glycerol. It was concluded that the Ni(II) species present on the catalysts are strongly dependent on Ni(II) loading. As Ni(II) content increases NiO nanocrystals are formed; the Ni(0) sites obtained from the reduction of these nanocrystals are responsible for the catalytic activity. On the other hand, at high Ni(II) contents the NiO nanocrystal size increases and as a consequence de intrinsic catalytic activity decreases. [ABSTRACT FROM AUTHOR]

Highlights: [•] Highest activity for glycerol the steam reforming was achieved with Ni(10)Mg(3)Al. [•] Low contents of Mg(II) favours Ni dispersion and metallic area. [•] Linear relation is verified between H2 yield and Ni dispersion for catalysts with Mg. [•] Catalyst without Mg(II) has the more active Ni sites. [•] Carbon formation related to basic character, minimized at high contents of Mg(II). [Copyright &y& Elsevier]

Abstract: The aim of this work is to study the catalytic activity of Ni(10%) based catalysts supported over ã-Al2O3 modified with Mg (3%) for the steam reforming of glycerol. Catalysts have been prepared by incipient wetness impregnation method; analysing the effect of the calcination temperature of the modified support and the calcination temperature of the catalysts. Catalysts were characterized by temperature programmed reduction, (TPR), x-ray diffraction (DRX) and BET surface area. All catalysts were tested for this reaction in a fixed bed reactor. The best performance was achieved with the catalyst calcined at 500 °C being the optimum calcination temperature for the modified support of 900 °C This behaviour is ascribable to the formation of MgAl2O4 spinel which favours the dispersion of Ni°, responsible of the catalytic activity. [Copyright &y& Elsevier]

The present work explores the hydrogenolysis of glycerol to produce 1,2-propanediol in vapor phase at atmospheric pressure over copper catalysts supported on mesoporous alumina. Catalysts were prepared by alumina impregnation varying CuO loading between 3 wt% and 30 wt%. The textural and structural characteristics of the catalysts were determined by N 2 sorptometry (BET), powder X-ray diffraction (PXRD), temperature programmed reduction (TPR) and N 2 O chemisorption (copper metallic area). The characterization showed that all catalysts present textural properties characteristic of mesoporous solids, such as the adsorption isotherms which are type IV. Based both on characterization and activity results, it was possible to conclude that the yield to 1,2-propanediol presented a non-monotonic dependence on total copper metallic area. In addition, it was proved that 1,2-propanediol production is associated with the presence of highly dispersed CuO phase in the solids. Promising results were obtained with CuO(15)Al catalysts, taking into account that the performance can be improved by increasing residence time. [ABSTRACT FROM AUTHOR]