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Flexible glass photonics is a cutting-edge technological and scientific research field that, thanks to a very broad spectrum of applications, has tremendously grown during the last decade and is now a strategic topic. Here, we present the results of the spectral transmittance and reflectance of a 10-layer SiO2/TiO2 1D photonic crystal deposited on a flexible polymeric substrate under different bending conditions, obtained with a home-made adjustable sample holder.

TiO2 nanoparticles obtained by microwave-assisted hydrothermal synthesis were subjected to facile post-processing based on vacuum annealing. The resulting defective (TiO2-x) material showed extended light absorption in the visible range, enhancing sunlight compatibility. Structural and optical characterization point to the arising of an Urbach tail as the main reason. TiO2-x was then employed as photocatalyst for the inactivation of ciprofloxacin, an emerging environmental threat and source of antimicrobial resistance, under sunlight. TiO2-x performed significantly better than its parent compound and mechanistic analysis of the degradation pathway indicates that this material is a promising candidate for solar treatment of fluoroquinolones residues in water. [ABSTRACT FROM AUTHOR]

Ordered SiO2:Er3+ inverse opal films are fabricated by sol–gel technique in combination with a self‐assembly method to examine their potential as a suitable platform to tailor the spontaneous emission lifetime of Er3+ ions and its concentration quenching (CQ). Good ordering on long‐range scale is evidenced by means of scanning electron microscopy, whereas reflectance measurements display a green bright color, as it results from optical Bragg diffraction from the (111) crystal planes. Moreover, it is observed that the spontaneous decay rates (SDRs) of the inverse opals are suppressed, in contrast to the corresponding reference samples, due to the modulation of the effective refractive index (neff), in agreement with the virtual cavity model. At the same time, the reduced CQ of Er3+ is attributed to the periodic empty cavity of the inverse opals. These results demonstrate that inverse opals can provide a tool for the enhancement of near‐infrared (NIR) luminescence. [ABSTRACT FROM AUTHOR]

WO3/BiVO4 films obtained by electrochemical deposition of BiVO4 over mesoporous WO3 were applied to the photoelectrochemical degradation of selected emerging contaminants (ketoprofen and levofloxacine) in aqueous solutions. The WO3/BiVO4 films in this work are characterized by a mesoporous morphology with a maximum photoconversion efficiency >40% extending beyond 500 nm in Na2SO4 electrolytes. Oxygen was found to be the dominant water oxidation product (ca. 90% faradaic yield) and no evidence for the photogeneration of OH radicals was obtained. Nevertheless, both 10 ppm levofloxacine and ketoprofen could be degraded at WO3/BiVO4 junctions upon a few hours of illumination under visible light. However, while levofloxacine degradation intermediates were progressively consumed by further oxidation at the WO3/BiVO4 interface, ketoprofen oxidation byproducts, being stable aromatic species, were found to be persistent in aqueous solution even after 15 hours of solar simulated illumination. This indicates that, due to the lower oxidizing power of photogenerated holes in BiVO4 and a different water oxidation mechanism, the employment of WO3/BiVO4 in photoelectrochemical environmental remediation processes is much less universal than that possible with wider band gap semiconductors such as TiO2 and WO3. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of the thickness determination of thin gold overlayers deposited on silicon bulk substrates by looking at the electron backscattering coefficient involved in scanning electron microscopy (SEM). A Monte Carlo code, used to calculate the backscattering coefficient, together with a simple experimental setup, which uses a conventional SEM, allow to determine thin film thickness (in the range 25-200 nm) with an estimated accuracy of 20%. This adds obviously new potentiality to SEM. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Mg films containing Fe–Zr mixed additives were prepared by rf sputtering and their hydrogen sorption kinetic was studied by Sievert technique. We observed that mixed Fe–Zr additives improve the H2 desorption kinetics better than singly Fe or Zr. X-ray diffraction analysis evidences that mixed additives optimize the Fe distribution that forms smaller clusters than in Mg sample with single Fe catalyst. The presence of mixed additives, with Fe having larger diffusivity than Zr, contributes to maintain the atomic Zr dispersion in the Mg matrix, thus, favoring the presence of a greater number of nucleation sites for MgH2 to Mg transformation. [ABSTRACT FROM AUTHOR]

Mg films containing Fe–Zr mixed additives were prepared by rf sputtering and their hydrogen sorption kinetic was studied by Sievert technique. We observed that mixed Fe–Zr additives improve the H2 desorption kinetics better than singly Fe or Zr. X-ray diffraction analysis evidences that mixed additives optimize the Fe distribution that forms smaller clusters than in Mg sample with single Fe catalyst. The presence of mixed additives, with Fe having larger diffusivity than Zr, contributes to maintain the atomic Zr dispersion in the Mg matrix, thus, favoring the presence of a greater number of nucleation sites for MgH2 to Mg transformation. [ABSTRACT FROM AUTHOR]

Mg and Nb-doped Mg films were deposited by rf magnetron sputtering. Morphological and structural analysis were performed by scanning electron microscopy and x-ray diffraction. The desorption kinetics has been investigated by using a Sievert-type apparatus. The overall activation energy and the reaction order controlling desorption are (141±5) kJ mol-1 H and n≈4 for Mg and (51±5) kJ mol-1 H and n≈1 for Nb-doped (5 at. %) Mg. It is suggested that Nb atoms dispersed in the MgH2 grains catalyzes the dissociation of the hydride phase and that the rate limiting step in the H2 desorption is given by the H atomic migration through interconnected transformed domains of h-Mg. [ABSTRACT FROM AUTHOR]

Mg and Nb-doped Mg films were deposited by rf magnetron sputtering. Morphological and structural analysis were performed by scanning electron microscopy and x-ray diffraction. The desorption kinetics has been investigated by using a Sievert-type apparatus. The overall activation energy and the reaction order controlling desorption are (141±5) kJ mol-1 H and n≈4 for Mg and (51±5) kJ mol-1 H and n≈1 for Nb-doped (5 at. %) Mg. It is suggested that Nb atoms dispersed in the MgH2 grains catalyzes the dissociation of the hydride phase and that the rate limiting step in the H2 desorption is given by the H atomic migration through interconnected transformed domains of h-Mg. [ABSTRACT FROM AUTHOR]

Bioplastics possess the potential to foster a sustainable circular plastic economy, but their end-of-life is still challenging. To sustainably overcome this problem, this work proposes the hydrothermal carbonization (HTC) of residual bioplastics as an alternative green path. The focus is on cellulose acetate - a bioplastic used for eyewear, cigarette filters and other applications - showing the proof of concept and the chemistry behind the conversion, including a reaction kinetics model. HTC of pure and commercial cellulose acetates was assessed under various operating conditions (180-250 °C and 0-6 h), with analyses on the solid and liquid products. Results show the peculiar behavior of these substrates under HTC. At 190-210 °C, the materials almost completely dissolve into the liquid phase, forming 5-hydroxymethylfurfural and organic acids. Above 220 °C, intermediates repolymerize into carbon-rich microspheres (secondary char), achieving solid yields up to 23 %, while itaconic and citric acid form. A comparison with pure substrates and additives demonstrates that the amounts of acetyl groups and derivatives of the plasticizers are crucial in catalyzing HTC reactions, creating a unique environment capable of leading to a total rearrangement of cellulose acetates. HTC can thus represent a cornerstone in establishing a biorefinery for residual cellulose acetate., (© 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.)