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ZrB2-based laminates were produced by tape casting and pressureless sintered at 2150°C in argon atmosphere using silicon nitride as sintering aids. Two different configurations were considered: planar (tile) and tubular (roll). After sintering, the laminates reached different relative densities depending on their composition (with or without SiC additions as secondary phase) or the final shape (tiles or rolls). Traces of the formation of oxygen\xE2\x80\x90free crystalline phases such as B4C and BN were found in all samples. The RT flexural strength of bars cut from the tile configuration was mainly affected by the coarse microstructure, residual porosity, and layer stacking sequence. A very low scattering of the flexural strength values was registered in ZrB2-SiC laminates because of the homogeneous microstructure and the absence of any defects between the layers. Tape casting allowed the production of thin homogenous laminates with a significant reduction of weight and a careful microstructure control. [ABSTRACT FROM AUTHOR]

ZEBRA batteries (Zero Emission Battery Research Activities) for their high energy and power density are one of the possible solutions to electrical storage for stationary applications. These systems are based on nickel chloride-sodium cells operating at high temperatures (about 270°–350 °C), and rely on a ceramic β”-alumina tube or planar membrane as solid electrolyte. The ceramic process needed to produce the membrane electrolyte has a key role in enhancing and adapt the battery performance to the specific requirements for stationary and mobile applications. Minimal variations in composition or processing strongly influence the final properties of the storage device. The aim of this work was to examine in detail the relevant steps needed to obtain ceramic β”-alumina membranes with suitable morphological-structural characteristics, from powder synthesis to planar electrolyte forming and sintering. In particular, the reactive sintering processes and the influence of thermal treatments on the chemical-structural properties of the ceramic materials were deeply investigated. It was found that a high temperature calcination is a key step to obtain membranes with suitable mass density, high β’’-alumina content and optimum ionic conductivity. [ABSTRACT FROM AUTHOR]

The optical band gap energy and the electronic processes involved are important parameters of a semiconductor material and it is therefore important to determine their correct values. Among the possible methods, the spectrophotometric is one of the most common. Several methods can be applied to determine the optical band gap energy and still now a defined consensus on the most suitable one has not been established. A highly diffused and accurate optical method is based on Tauc relationship, however to apply this equation is necessary to know the nature of the electronic transitions involved commonly related to the coefficient n . For this purpose, a spectrophotometric technique was used and we developed a graphical method for electronic transitions and band gap energy determination for samples in powder form. In particular, the n coefficient of Tauc equation was determined thorough mathematical elaboration of experimental results on TiO 2 (anatase), ZnO, and SnO 2 . The results were used to calculate the band gap energy values and then compared with the information obtained by Ultraviolet Photoelectron Spectroscopy (UPS). This approach provides a quick and accurate method for band gap determination through n coefficient calculation. Moreover, this simple but reliable method can be used to evaluate the nature of electronic transition that occurs in a semiconductor material in powder form. [ABSTRACT FROM AUTHOR]

Synthetic hydroxy-apatite was tested as a potential new material for CO2 capture at high temperature, over the operation limit of CaO-based sorbents. Some porous granules of hydroxy-apatite were prepared ad hoc. They were shown to absorb CO2 upon dehydroxylation in the very high temperature range of 900-1200 °C, resulting in A-type carbonated apatite. No appreciable decay of the absorbing capacity was observed with a higher number of absorbing-desorbing cycles, differently from what happens in a conventional chemical sorbent, e.g. calcined natural calcium carbonate. The CO2 carrying capacity was maximum at 1000-1100 °C and very close to the theoretical limit of 2.6% by mass. The macro-granule porosity network appeared to be effective in making the sites available for CO2 capture. At first glance, the process appeared to be chemically controlled. The pre-treatment temperature of the porous granules also had an impact on the sorption capacity. As a first proof of concept, the results obtained by thermogravimetric analysis, and supported by FTIR and XRD analysis, were confirmed by tests carried out in a laboratory-scale reactor, operated as a fixed bed. [ABSTRACT FROM AUTHOR]

Abstract: A thin compact layer of TiO2 deposited on the conductive transparent substrate of a dye-sensitized solar cell photoanode, (blocking layer, BL) can enhance the performances of the entire device. In this paper, an optimized spin coating process using an alcoholic TiCl4 solution was developed and correlated to the final properties of the layer. The physicochemical characteristics of the precursor solution and the spin coating parameters were optimised to obtain a uniform layer. XRD, FE-SEM, UV–Vis spectroscopy, AFM, cyclic voltammetry and electrochemical impedance spectroscopy were used to evaluate the influence of the number of deposition cycles on the TiO2 layer. The results were compared with those obtained using a conventional dip coating technique, showing that the newly developed spin coating process produces blocking layers with superior properties. Finally, analyses of the photovoltaic performances of the complete cell confirmed that an optimized blocking layer can lead to an improvement of the solar conversion efficiency of about 84%. [Copyright &y& Elsevier]

[Display omitted] • Mechanical long-term stability of full ceramic membranes was studied. • 100 h of exposure at 750 °C in different atmospheres H 2 , CO 2 , H 2 + CO 2 are evaluated. • In H 2 + CO 2 the membrane shows a slight decrease in flexural strength and hardness. • In H 2 + CO 2 no evident morphological or structural changes. • Promising and stable hydrogen permeation flux were recorded. This work investigates, for the first time, the hydrogen permeation of BaCe 0.65 Zr 0.20 Y 0.15 O 3-δ -Ce 0.8 Gd 0.2 O 2-δ (BCZY-GDC) asymmetric membranes for 100 h, using wet 15% CO 2 in Ar as sweep gas. In the same frame, ex-situ aging tests were performed for 100 h exposure at 750 °C in different atmospheres (H 2 , CO 2 , H 2 + CO 2), to evaluate the phase, microstructure, and mechanical long-term stability of this system. The thermal aging in H 2 -atmosphere leads to lower flexural strength caused by a microstructure embrittlement of the BCZY-GDC asymmetric membrane, due to chemical expansion/contraction of the GDC cell after the aging cycle. Indeed, micro-cracking of GDC grains, that decreases the composite hardness, is observed in symmetric (pressed pellet) membranes. The aging in CO 2 causes a slightly increase in flexural strength values due to the formation of sub-micrometric Zr-doped ceria-BaCO 3 phases at the expense of the perovskite. Higher hardness values related to the emerging of BaCO 3 islands on the symmetric membrane surface were also recorded. In H 2 + CO 2 atmosphere (real testing condition), the membrane shows a slight decrease in flexural strength and hardness while no evident morphological or structural changes (except the BaCO 3 formation in traces) were observed. This study highlights that promising and stable hydrogen permeation flux values can be recorded using the asymmetric configuration for 100 h, using wet 15% CO 2 in Ar as sweep gas. Neither structural nor morphological modification of the membrane were detected after the testing. [ABSTRACT FROM AUTHOR]

Abstract: The high sintering temperature of Yttrium doped barium zirconate (BZY), the most promising high temperature proton conductor (HTPC) for Intermediate Temperature (400–750 °C) Solid Oxide Fuel Cells (IT-SOFCs), has been reduced by using ZnO as a sintering aid. Obtaining a dense electrolyte at a reduced temperature allows conventional fuel cell preparation methods. A reproducible spin coating method to fabricate highly performing anode supported button cells with dense micrometric BZYZn electrolyte layers has been developed. The electrochemical characterization of button cells at 600 °C shows promising performance, higher than that of comparable fuel cells from literature. [Copyright &y& Elsevier]

Abstract: Sub-micrometer powder (100–150nm diameter) of Yb-doped yttrium oxide was obtained, for the first time, by microwave-assisted polyol (diethylene glycol, DEG) method. This method is based on fast and homogeneous increase of temperature, due to the microwave heating, and on addition of the hydrolysing agent (water) at high temperature. This promotes a fast nucleation followed by a controlled growth of nuclei. Different procedures were used to process the as-synthesized powders. In some cases washing by ultrapure water was used to dissolve nitrate and DEG by-products, this treatment allowed the use of a lower calcination temperature (150–200°C less) to obtain the crystalline phase. Analysis of the calcined powder showed different levels of structures: from nanocrystal (10–15nm), to primary particles (100–150nm), to micrometer soft aggregates (2–4μm). The microwave-assisted polyol method resulted an easy way to dope yttria with the desired amount of Yb3+. This work was carried out in order to prepare particles to be used as rare-earth doped Y2O3 and YAG polycrystalline transparent ceramic for laser source applications. [Copyright &y& Elsevier]

In this work new energy storage components were prepared depositing films made of polyaniline (PANI) modified with gold/magnetite nanoparticles on flexible graphite foils. Three types of composite materials termed PANI/Fe 3 O 4 , PANI/Au/Fe 3 O 4 and PANI/Au/Fe 3 O 4 @Yne (where @Yne is a propynylcarbamate group) were obtained by electrosynthesis. Galvanostatic charge-discharge (CD) and impedance tests (EIS) were performed to verify their efficiency in charge storage properties: for the gold-containing electrodes PANI/Au/Fe 3 O 4 and PANI/Au/Fe 3 O 4 @Yne areal capacities values of 45.6 and 46.5 mAh cm−2 were found in 0.5 M H 2 SO 4 + 0.1 M LiClO 4 electrolyte solution at a current density of 0.5 mA cm−2. These values are twofold higher than those found for PANI/Fe 3 O 4 electrodes and fourfold greater than those for PANI alone (11.0 mAh cm−2). In turn PANI/Au/Fe 3 O 4 and PANI/Au/Fe 3 O 4 @Yne were employed to assemble gel-state symmetric devices. CD, EIS and longtime resistance tests were made on the new devices that displayed an areal capacities of 100.0 mAh cm−2 for PANI/Au/Fe 3 O 4 and 73.6 mAh cm−2 PANI/Au/Fe 3 O 4 @Yne respectively. To our knowledge this is the first time that AuNP–modified magnetite nanoparticles are used in energy storage devices preparation. Image 1 • PANI and PANI-nanocomposites containing Fe 3 O 4 and AuNP were electrodeposited on graphite foil. • The three-component nanocomposites display the key qualities for energy storage electrode materials. • The PANI-based nanocomposites present good electrochemical capacities properties. [ABSTRACT FROM AUTHOR]

Proton-conducting ceramic materials have emerged as effective candidates for improving the performance of solid oxide cells (SOCs) and electrolyzers (SOEs) at intermediate temperatures. BaCeO 3 and BaZrO 3 perovskites doped with rare-earth elements such as Y 2 O 3 (BCZY) are well known for their high proton conductivity, low operating temperature, and chemical stability, which lead to SOCs' improved performance. However, the high sintering temperature and extended processing time needed to obtain dense BCZY-type electrolytes (typically > 1350 °C) to be used as SOC electrolytes can cause severe barium evaporation, altering the stoichiometry of the system and consequently reducing the performance of the final device. The cold sintering process (CSP) is a novel sintering technique that allows a drastic reduction in the sintering temperature needed to obtain dense ceramics. Using the CSP, materials can be sintered in a short time using an appropriate amount of a liquid phase at temperatures < 300 °C under a few hundred MPa of uniaxial pressure. For these reasons, cold sintering is considered one of the most promising ways to obtain ceramic proton conductors in mild conditions. This review aims to collect novel insights into the application of the CSP with a focus on BCZY-type materials, highlighting the opportunities and challenges and giving a vision of future trends and perspectives.

The "on-demand" capture and utilization of CO 2 is effectively realized with a readily accessible dual function organic composite. The covalent and controlled derivatization of graphene oxide (GO) surface with naturally occurring arginine led to a "smart" material capable of capturing (chemisorption) CO 2 from high-purity flue-gas as well as low-concentration streams (i. e. direct air capture) and concomitant chemical activation toward the incorporation into cyclic carbonates. The overall integrated CO 2 capture and conversion (ICCC) strategy has been fully elucidated mechanistically via dedicated computational, spectroscopic and thermal analyses., (© 2024 Wiley-VCH GmbH.)

It is well known that the prolonged exposure to UV radiation from sunlight can compromise human health and is particularly damaging to the skin, leading to sunburn, photo-aging and skin cancer. Sunscreen formulations containing UV-filters present a barrier against solar UV and help to mitigate the harmful effects however, concern about their safety for both human and environmental health is still a much-debated topic. EC regulations classify UV-filters depending on their chemical nature, particle size, and mechanism of action. Furthermore, it regulates their use in cosmetic products with specific limitations in terms of concentration (organic UV filters) and particle size and surface modification to reduce their photo-activity (mineral UV filters). The regulations have prompted researchers to identify new materials that show promise for use in sunscreens. In this work, biomimetic hybrid materials composed of titanium-doped hydroxyapatite (TiHA) grown on two different organic templates, derived from animal (gelatin - from pig skin) and vegetable (alginate - from algae) sources. These novel materials were developed and characterized to obtain sustainable UV-filters as a safer alternative for both human and ecosystem health. This 'biomineralization' process yielded TiHA nanoparticles that demonstrated high UV reflectance, low photoactivity, good biocompatibility and an aggregate morphology which prevents dermal penetration. The materials are safe for topical application and for the marine environment; moreover, they can protect organic sunscreen components from photodegradation and yield long-lasting protection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Trigonal-prismatic coordinated transition metal dichalcogenides (TMDCs) are formed from stacked (chalcogen)-(transition metal)-(chalcogen) triple layers, where the chemical bond is covalent within the triple layers and van der Waals (vdW) forces are effective between the layers. Bonding is at the origin of the great interest in these compounds, which are used as 2D materials in applications such as catalysis, electronics, photoelectronics, sensors, batteries and thermoelectricity. This paper addresses the issue of modelling the structural disorder in multilayer TMDCs. The structural model takes into account stacking faults, correlated displacement of atoms and average crystallite size/shape, and is assessed by simulation of the X-ray diffraction pattern and fitting to the experimental data relative to a powdered sample of MoS 2 exfoliated and restacked via lithiation. From fitting, an average crystallite size of about 50 Å, nearly spherical crystallites and a definite probability of deviation from the fully eclipsed atomic arrangement present in the ordered structure are determined. The increased interlayer distance and correlated intralayer and interlayer atomic displacement are attributed to the presence of lithium intercalated in the vdW gap between triple layers (Li/Mo molar ratio of about 0.06). The model holds for the whole class of trigonal-prismatic coordinated TMDCs, and is suitably flexible to take into account different preparation routes., (© Federica Ursi et al. 2023.)

Electroconductive biomaterials have been emerged to support the recovery of the degenerated electrically conductive tissues, especially the cardiac ones after myocardial infarction. This work describes the development of electroconductive scaffolds for cardiac tissue regeneration by using a biocompatible and conductive polymer - i.e. poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) - combined with a biomimetic polymer network of gelatin. Our approach involves the use of dehydrothermal (DHT) treatment in vacuum conditions to fabricate suitably stable scaffolds without using any additional crosslinking agent. The resulting scaffolds mimic the Young modulus - an essential mechanical performance - of native cardiac tissue and are endowed with a well-interconnected porosity coupled with a good swelling ability and stability in physiological conditions. Additionally, the presence of PEDOT:PSS is able to enhance the electroconductivity of resulting materials. All the scaffolds are non-cytotoxic towards H9C2 cardiomyoblasts and the presence of PEDOT:PSS enhances cell adhesion - especially at early timeframes, an essential condition for a successful outcome after the implantation - proliferation, and spreading on scaffolds. Considering the permissive interaction of scaffolds with cardiomyoblasts, the present biomimetic and electroconductive scaffolds display potential applications as implantable biomaterials for regeneration of electroconductive tissues, especially cardiac tissue, and as a promising 3D tissue model for in vitro biomolecules screening., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)