Search

The tailoring of multi-tasking perovskite oxide-based electrodes for solid oxide cells has shown growing interest. The development of flexible structures represents a crucial step towards the design of symmetric and possibly SOFC/SOEC reversible systems. In this work, low (0.5 mol%) B-site Pt-doping in a lanthanum strontium ferrite is presented as a successful approach to enhance the parent perovskite properties as both SOC air and fuel electrode. Structural, morphological and electrochemical characterizations of La0.6Sr0.4Fe0.995Pt0.005O3-δ (LSFPt005) are provided and compared to the undoped compound. LSFPt005-symmetric devices are tested as CO-SOFCs and CO2-SOECs at 850 °C, respectively, obtaining a maximum power density of 301 mW/cm2 and a current density of 0.82 A/cm2 at 1.5 V. Insights of cell operating mechanisms are provided through electrochemical impedance spectroscopy.

Highly performing perovskite-based anodes for methane mixtures-fueled solid oxide fuel cells (SOFC) are proposed. Catalytic activities of La0.6Sr0.4Fe1-xPdxO3-δ (LSFPd) with x = 0.05, 0.1 toward dry reforming of methane (DMR) and partial oxidation of methane (POM) reactions are investigated. The addition of (30wt%) Ce0.85Gd0.15O2-δ (GDC) and of (30wt%) Ni(5wt%)-GDC to the perovskite compounds was evaluated to enhance both electrocatalytic and electrochemical properties. Electrolyte-supported cells based on La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) pellets and LSFPd perovskite oxides at both electrodes are fabricated and tested using CH4, CH4/Ar and CH4/CO2 mixtures in the 750–850°C temperature range. Fuel cell tests using anodic mixtures such as LSFPd/GDC and LSFPd/Ni-GDC are also performed. A discussion based on the comparison between catalytic and electrochemical results and on the possible reforming and/or oxidation reactions taking place at the anode is detailed.

The development of low-melting mixtures is crucial for the diffusion of sustainable and green alternative energy sources, namely, CSP. Ternary mixtures containing sodium, potassium, and calcium are extremely promising as thermal fluids due to their good thermophysical properties, low toxicity and cost. Most literature studies on ternary mQ4ixtures refer to a particular commercial composition and there are few data regarding ternary phase diagrams. Thus, for improving the current understanding on this topic, further theoretical and experimental investigation on ternary mixtures is of utmost interest. An experimental campaign was conducted to study the binary subsystems of the ternary mixtures and develop a regular solution model for simulating the ternary phase diagram. To validate the model, several data were determined using an innovative experimental rheometric method. The results showed that a ternary contribution in the regular solution model is necessary and an empirical expression for this ternary parameter was proposed and validated.

In this work, we report the investigation of Fe and Co triphenylcorrole complexes supported on two different carbon supports as eletrocatalysts for the ORR in neutral pH media, comparing their performances with the corresponding tetra- phenylporphyrin complexes. Cyclic voltammetry experiments were acquired in neutral phosphate buffer demonstrating that corroles exhibit a superior catalytic activity towards ORR than porphyrins, as demonstrated by more positive oxygen reduc- tion peak potential (Epr) and half-wave potential (E1/2) values of corroles. Also, iron complexes performed better than cobalt ones, showing an ORR activity even superior to that of platinum taken as reference, as demonstrated by RDE experiments. We investigated the role of the axial ligand on the ORR activity of the macrocycles, and we found that Epr and E1/2 values are more positive along the series: PPh3Co < py2Co = μ-oxoFe2 < FeCl. By contrast, there was not much difference in activity support- ing the porphyrinoids on carbon nanotubes or carbon black pearls, indicating that the effect of carbon support is less im- portant to that of the axial ligand. The results allowed pointing at iron corroles as a promising class of molecular catalysts for application as cathodes in biolectrochemical systems at neutral pH, such as microbial fuel cells.

Controlled drug release holds promise to revolutionize medicine, particularly if short-term and long-term release can be combined in a single system. We present here a new pulsatile release system,...

The production of electric energy from solar radiation is nowadays one of the most investigated and developed “carbon free” technology. A throughout investigation of the ceramics most commonly used as heat transfer fluids and/or heat storage materials for concentrating solar power systems (i.e. alkaline and heart alkaline nitrate/nitrite mixtures) is here reported. The study stems by the need to base materials selection on an accurate and critical knowledge of all their characteristics, including their thermophysical, environmental compatibility, and economic features. At this purpose, a rating criterion have been established, to readily show the advantages and disadvantages of each material, and to highlight which characteristics of the examined materials need to be further investigated and improved. Nitrate/nitrite mixtures have also been compared with other ceramics used for thermal storage, such as solid fillers, liquid metals, other salt mixtures, or phase change materials.

Structural and microstructural investigations of Pd-doped lanthanum strontium ferrite with stoichiometry La0.6Sr0.4Fe0.95Pd0.05O3-? (LSFPd) were carried out under oxidizing and reducing conditions using XRD, Rietveld refinement, XPS, SEM, and TEM analyses. LSFPd exhibited a smart behaviour with a reversible redox structural transformation occurring upon switching from air to hydrogen and then back to air. Exsolution of nanometric metal particles was observed after reduction, and reincorporation of metal cations onto the perovskite structure was confirmed after reoxidation. The electrochemical performances were evaluated on electrolyte supported cells using LSFPd as symmetric electrodes. The self-regenerating redox process largely improved the anodic performance of LSFPd-based SOFCs because it mitigates the coarsening of metallic electrocatalysts at high temperature promoting a redox stable behaviour. Fuel cell tests revealed promising performance in terms of maximum power output and redox stability.

In the path of direct energy conversion and wastewater disposal through microbial fuel cells (MFCs), the oxygen reduction reaction (ORR) plays a pivotal role. However, kinetic limitations hinders the spread of such technology requiring the use of a catalyst to develop efficient and cost effective devices. Herein we report a facile method for the preparation of iron-based catalyst supported on graphene oxide (GO) obtained by electrochemical exfoliation of graphite in aqueous solution of ammonium sulfate. Two different strategies to include nitrogen functionalities on/in GO matrix have been used, such as one-step nitrogen-doping in solution and post treatments based on annealing with ammonia gas. Iron (II) phthalocyanine (FePc) was used as iron source and deposited on GO by pyrolysis-free impregnation. Tuning the adjustable parameters governing the materials preparation allowed producing GO nanosheets with unique morphology and surface properties for enhancing the interaction with FePc. By combining the use of microscopy, electrochemical and spectroscopic techniques, a correlation between structure and surface chemistry of the prepared materials with catalytic activity towards ORR was established. The applicability of iron-based materials as ORR cathodes was evaluated by assembling single chamber air-cathodes MFCs, which power and voltage generation over time were acquired. The obtained results demonstrated that FePc/GO-based electrocatalysts can be used for electricity generation and waste treatment at the cathode side of MFCs.

In this work, we initially report a detailed advancement in the utilization of metal-N4 chelate macrocycles in the oxygen reduction reaction (ORR). Then, iron(II) phthalocyanines supported on two different carbon-based supports specifically carbon nanotube and black pearl (carbon spheres) were synthesized and their activities toward ORR in alkaline media were studied. With the help of physical and surface characterization like Raman, BET, XRD, XPS, and electron microscopy analysis, the similarity in surface chemistry and surface area of the materials and the differences in the structure and morphology of the supports were established. This work also brings forth the effect of support properties on the electrocatalytic activity of the materials by a detailed electrochemical analysis using rotating disk electrode in oxygen saturated 0.1 M KOH. Comparison with existing literature on Fe-phthalocyanine supported on diverse carbon support is presented.

Reversible solid oxide cell (RSOC) technology allows use of a single device to efficiently derive chemicals from power (power-to-fuel) and power from chemicals (fuel-to-power). Fuel flexibility is a key aspect, as developing SOCs able to operate on fuels other than hydrogen can ease their integration into existing infrastructure. In addition, H2O and/or CO2 reduction is favorable in SOECs as polarization losses are reduced at high temperature. Here, a composite fuel electrode, 60 wt.% La0.6Sr0.4Fe0.8Mn0.2O3-δ (LSFMn) and 40 wt.% (5 wt.% Ni)-containing Ce0.85Sm0.15O2-δ (Ni-SDC) was investigated in H2-fueled, CO-fueled SOFCs and for CO2 reduction in SOEC mode. In reducing conditions, Fe exsolved from the LSFMn perovskite formed a Ni-Fe alloy with Ni present on SDC. The composite fuel electrode showed remarkable activity for CO2 reduction with a current density output of 1.40 A cm-2 (1.5 V) at 850 °C. SOFC/SOEC cell reversibility was obtained in different CO2:CO mixtures. Electrochemical impedance spectroscopy analysis was used to better understand cell mechanisms in SOFC and SOEC mode.

Extra virgin olive oil (EVOO) is defined as a functional food as it contains numerous phenolic components with well-recognized health-beneficial properties, such as high antioxidant and anti-inflammatory capacity. These characteristics depend on their structural/conformational behavior, which is largely determined by intra- and intermolecular H-bond interactions. While the vibrational dynamics of isolated compounds have been studied in a number of recent investigations, their signal in a real-life sample of EVOO is overwhelmed by the major constituent acids. Here, we provide a full characterization of the vibrational spectroscopic signal from commercially available EVOO samples using Inelastic Neutron Scattering (INS) and Raman spectroscopies. The spectra are dominated by CH2 vibrations, especially at about 750 cm−1 and 1300 cm−1. By comparison with the spectra from hydroxytyrosol and other minor phenolic compounds, we show that the best regions in which to look for the structure–activity information related to the minor polar compounds is at 675 and 1200 cm−1 for hydroxytyrosol, and around 450 cm−1 for all minor polar compounds used as reference, especially if a selectively deuterated sample is available. The regional origin of the EVOO samples investigated appears to be related to the different amount of phenolic esters versus acids as reflected by the relative intensities of the peaks at 1655 and 1747 cm−1.

Extra virgin olive oil (EVOO) is one of the most important ingredients as well as the main source of lipids in the Mediterranean diet. It is known to contain biologically relevant phenolic componen...

Thermal energy storage technology with Phase Change Materials (PCM) is an attractive option to optimise energy resources and to recover and promote excess heat. The phase change behaviour of PCM requires advanced research to understand and better control the thermal energy storage using PCM, which is a crucial step to develop a powerful latent storage system. This paper aims to analyse the multiphysics phenomena of three regenerator configurations, horizontal case and two injection direction of Heat Transfer Fluid (HTF): top and bottom in vertical case. The study is done for the charge and discharge cycles of the solid-solid and solid-liquid phase transitions of PCM. First, the temperature dependence of the thermal and physical properties of paraffin as PCM is characterised. Second, an experimental study of an annular latent storage system was carried out. Also, an experimental mesh method was introduced to compare the energy behaviour of the three cases. Third, a numerical analysis of the experimental storage unit with low thermal diffusion is performed. The experimental results are confronted with the numerical results obtained with ANSYS Fluent and COMSOL Multiphysics commercial software. Last, the three configurations are compared to a reference case without gravitational field. The results show that specific mechanisms control the thermal and energetic behaviour of the regenerator. Furthermore, several parameters, such as storage density, distribution of energy storage rate in the different regenerator components (PCM, HTF, and heat exchanger), were analysed. Altogether, the results supply important information to understand the dynamics of passive storage systems.

Perovskite oxides such as ferrites have been widely investigated for their remarkable electrochemical activity as SOFC electrodes. However, their phase instability in reducing conditions remains an issue for anode application. The role of Mn substitution into B-site of La0.6Sr0.4FeO3-δ (LSF) perovskite oxide was investigated. New insights on the structural evolution of La0.6Sr0.4Fe0.8Mn0.2O3-δ (LSFMn) upon high temperature reduction were revealed. In oxidizing atmosphere, Mn substitution reduces the oxygen vacancy concentration while, switching to reducing conditions, it drives the transition from rhombohedral perovskite to single Ruddlesden-Popper phase, affecting the Fe0 exsolution. Redox-cycles of LSFMn were investigated and the properties of re-oxidized compounds were highlighted. The effect of Mn substitution on perovskite conductivity was also evaluated both in oxidizing and reducing conditions.

A structured catalyst for the dry reforming of methane (DRM) was investigated as a biogas pre-reformer for indirect internal reforming solid oxide fuel cell (IIR-SOFC). For this purpose, a NiCrAl open-cell foam was chosen as support and Ni-based samarium doped ceria (Ni-SmDC) as catalyst. Ni-SmDC powder is a highly performing catalyst showing a remarkable carbon resistance due to the presence of oxygen vacancies that promote coke gasification by CO2 activation. Ni-SmDC powder was deposited on the metallic support by wash-coating method. The metallic foam, the powder, and the structured catalyst were characterized by several techniques such as: N2 adsorption-desorption technique, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), focused ion beam (FIB), temperature programmed reduction (H2-TPR), and Raman spectroscopy. Catalytic tests were performed on structured catalysts to evaluate activity, selectivity, and stability at SOFC operating conditions.

The selection of a proper heat transfer (HTF) and storage (HSM) material is a key parameter in the design of a CSP system, especially in the employment of parabolic trough concentrating solar power plants (CSP). The use of nitrates as HTF, alternatively to thermal oils, can increase the CSP efficiency and several mixtures have been proposed at this aim. The most employed molten nitrate salt is the so called “solar salt” that presents several advantages but also a relative high liquidus temperature point of 238 °C. The use, either as HTF or HSM, of a low melting mixtures is currently considered a promising alternative to decrease the investment cost and improve the manageability of CSP plants. In this work, a low melting fluid was selected, composed of calcium, sodium and potassium nitrate, and proposed to be used both as HTF and HSM in a direct and active storage system. The electric LCOEs was calculated for a medium size (50 MWe) plant located at the Priolo Gargallo site (Sicily-Italy). In order to evaluate the obtained outcome, the identical procedure was carried out considering the same size and location, and the “solar salt” and a thermal oil as heat transfer fluids, with the former as storage medium. The comparison between the results show that there is a clear, although limited, economic benefit in using the ternary mixture.

Chemical storage systems are a promising innovative route to overcome the issue of the solar irradiation storage, resulting as cost effective and with high energy density. A main problem with these kinds of materials is to design a synthesis method for preparing stable reactive structures, presenting at the same time a high volumetric charging/discharging enthalpy. At this purpose, a size controlled spinel was produced, characterized and investigated regarding its thermophysical and kinetics properties. The obtained powder presents an average diameter between 100 and 200 µm and an energy density of 133 J/g and an experimental test was carried out to verify the spinel morphology stability under thermal cycles. The specific heat is similar to other structured chemical storage system and makes the spinel feasible to be used also as sensible accumulation medium. Despite the relatively high particles size, and the expected small exposed reactive area, the charging, and especially discharging reaction rates resulted particularly favourable and comparable with the reported behaviour of micrometric powders. The particularly simple preparation method plus the cost effectiveness of the precursors leads to a quite convenient expected cost for the storage material, absolutely similar to commercially available accumulation systems.

When designing a concentrating solar power (CSP) system, selection of a proper heat transfer fluid (HTF) material is a key, especially when employed in parabolic trough CSP plants. In particular, the use of low melting mixtures as an alternative to the widely commonly used “solar salt” can increase the CSP manageably and, as a result, several innovative nitrite/nitrate mixtures have been proposed. However, very few thermodynamics data are available for these compounds, especially regarding ternary compositions. One of the most interesting low freezing mixture is prepared with sodium and potassium nitrate together with sodium nitrite. The aim of this work is to investigate the thermodynamics properties of this ternary system, starting from its binary subunits, studying the phase diagram of this compound both experimentally and by a regular solution model. At this purpose, the literature phase diagrams of the binary subsystem were simulated in order to obtain the fitting parameters necessary for the employed semi-predictive tool. Then, the ternary system was modeled and the results showed very good agreement with the experimental points. It is quite interesting to note that both the theoretical and experimental results showed a low melting zone presenting greater sodium nitrate molar fractions with respect to sodium nitrite than previously reported in literature. This would lead to a decrease in the HTF price and an improvement regarding the fluid toxicity.

The vaporization/decomposition of single-phase BaCeO3 samples was studied by the Knudsen Effusion Mass Spectrometry technique in the overall temperature range 1647–1923 K. The partial pressures of the gaseous species BaO(g), CeO2(g) and CeO(g) were monitored as a function of temperature. The formation of reduced form of cerium oxide as a product of the high temperature decomposition of BaCeO3 under the given experimental conditions was suggested by the low value of the measured CeO2(g)/CeO(g) pressure ratio and confirmed by the XRD spectra of the vaporization residues. The equilibrium data were tentatively processed according to various heterogeneous equilibria that may be established in the cell: (i) BaCeO3(s) = BaO(g) + CeO2(s); (ii) BaCeO3(s) + CeO(g) = BaO(g) + Ce2O3(s); (iii) BaCeO3(s) = BaO(g) + CeO2(g). The corresponding enthalpy changes were calculated by the third-law method and the enthalpy of formation of BaCeO3 derived thereafter. The thermodynamic analysis confirms that the decomposition process forming CeO2(s) is very unlikely to occur under the high temperature, high vacuum conditions used in the present study. The analysis of process BaCeO3(s) = BaO(g) + CeO2(g), not involving solid products, was selected as the most reliable and leads to a value for the enthalpy of formation of barium cerate (Δf$$H_{{298}}^{^\circ }$$ (BaCeO3) = –1688.7 ± 6.2 kJ/mol) in agreement with the available calorimetric determinations.

The study and development of multi-component alkaline nitrates systems is of utmost interest to investigate low melting and low cost HTFs and HSMs, to be used in CSP plants. At this aim, several binary and ternary mixtures have been proposed as feasible and promising materials in the scientific literature. In order to evaluate the most feasible HTF and HSM, the simulation campaign proposed in this work was focused on economical and readily available compounds, ruling out rare and costly species. A semi-predictive model, based on the regular solution theory, was employed to draw the ternary phase diagrams of LiNO3/NaNO3/Ca(NO3)2 and LiNO3/KNO3/Ca(NO3)2, from which it was possible to select the lower melting zones and the compositions. The binary sub-systems were the starting point for the employed approach. The results showed a good agreement with literature experimental data, and new low melting compositions were simulated and experimentally validated. It is noteworthy that it was possible to identify in great detail the zones of the two ternaries presenting the lowest freezing points and this can allow the design of interesting and cost-effective low melting mixtures.

The present research utilizes archaeology and physical anthropology to reconstruct the demography, occupational stress markers and health conditions of individuals that lived during the medieval era in Santa Severa (Rome, Italy). The cemetery recovered during the restoration of the Castle of Santa Severa dates back to 1232 ± 40 BP (680–890 cal.)–1004 ± 30 BP (970–1060 cal.), as regards Casa del Nostromo, and to 883 ± 40 BP (1040–1220 cal.)–531 ± 35 BP (1380–1450 cal.) for Piazza della Rocca, according to 14C analyses on four bone samples corresponding to the most superior and inferior stratigraphic levels. This range of dates ascribes the burials to the transition period between the Early and Late medieval era. The goal of the present research was to analyze one of the largest Italian medieval communities using a morphological approach to reconstruct its osteobiography. The complex comprised a total of 455 individuals: 118 juveniles and 256 adults (M:F = 1.4). All age classes were represented, meaning that, even if the area were not completely excavated, the analyzed series could be considered representative of the population from which it comes. The sample exhibited a high degree of biomechanical stress related to daily tasks, mainly affecting the upper limbs and involving both the shoulder and the pelvic girdle. Several pathologies were detected; the most common appeared to be degenerative and infectious diseases, though some cases of congenital disorders could also be observed. Regarding the dental pathology, low frequencies of caries, abscesses and antemortem tooth loss were detected in spite of a high prevalence of dental calculus. These results seem to suggest that subsistence was based on both agriculture and farming.

Highly water-dispersible, redox-active 1D coordination polymers (CPs) have been synthesized using low-cost precursors. These CPs, containing chloranilic acid as organic ligand and a transition element, such as Fe and Mn as a metal center, form long-term stable slurries containing up to 100 g/L solid particles in aqueous media (0.5 M NaCl, 1 mg carbon nanotubes). Voltammetry studies showed that the iron-based particulate slurries exhibited three different redox stages with no metal plating. However, the suspensions with manganese-based coordination polymers experienced a metal plating process in the same potential window range as for the iron-based CPs. Moreover, the particulate suspension of iron-CPs shown longer-term stability than their isostructural analogs based on manganese. The 1D Fe-CPs were used as catholyte and anolyte in a symmetrical cell with a low-cost size exclusion cellulose membrane acting as a separator. The cell experienced a reversible capacity value of 45 mAh/g (225 mAh/L) at a current density value of 20 mA/g for 50 cycles (~12 days) at neutral pH. This study opens the possibility of using inexpensive coordination polymers as single bifunctional electrolyte material in aqueous batteries and other sustainable energy storage-related systems., J.M. greatly acknowledge the Funds of his doctoral grant, Materialsfor Health, Environment and Energy, from the University of Rome TorVergata (Italy). J.C.G. acknowledges support from the Spanish Ministry of Economy, Industry, and Competitiveness (MINECO) througha Ramon y Cajal Fellowship (RYC-2015-17722), the Retos Project(MAT2017-86796-R, AEI/FEDER/UE) and the PTI-FLOWBAT project(Ref. N°: 201980E101) from the Spanish Research Council (CSIC). J.M., B.M., and A.D. acknowledge the Regione Lazio for funding theresearch through the project POR FESR LAZIO 2014–2020, NoA0375-2020-36492.

In this work, crosslinked hydrocarbon-based cation exchange membranes have been developed for vanadium redox flow battery applications. By Friedel-Crafts alkylation of sulfonated poly(phenylene sulfide sulfone) (sPSS), membranes with various degrees of crosslinking have been prepared in one step. Among those, the membrane containing 9% of crosslinker (sPSScl9) represents the best solution. Owing to a much higher selectivity, battery self-discharge and capacity fading (tested over 100 charge/discharge cycles at 120 mA cm−2) of sPSScl9 outperform benchmark Nafion of comparable thickness (N212). Furthermore, the crosslinking strategy permits to obtain stable membranes even in highly oxidizing environments, due to a combination of crosslinking, that holds together the polymer chains, and oxidation of sulfides to sulfones that increases the rigidity of the backbone. As a result, sPSScl9 incubated in the presence of V(V) shows unchanged ion exchange capacity and proton conductivity, and a 10× reduction of vanadium permeability with respect to untreated membranes.

Cerium oxide nanoparticles (CNPs) are novel synthetic antioxidant agents proposed for treating oxidative stress-related diseases. The synthesis of high-quality CNPs for biomedical applications remains a challenging task. A major concern for a safe use of CNPs as pharmacological agents is their tendency to agglomerate. Herein we present a simple direct precipitation approach, exploiting ethylene glycol as synthesis co-factor, to synthesize at room temperature nanocrystalline sub-10 nm CNPs, followed by a surface silanization approach to improve nanoparticle dispersibility in biological fluids. CNPs were characterized using transmission electron microscopy (TEM) observations, X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) spectroscopy, dynamic light scattering (DLS) and zeta potential measurements. CNP redox activity was studied in abiotic systems using electron spin resonance (ESR) measurements, and in vitro on human cell models. In-situ silanization improved CNP colloidal stability, in comparison with non-functionalized particles, and allowed at the same time improving their original biological activity, yielding thus functionalized CNPs suitable for biomedical applications.

Polyunsaturated fatty acids have been reported to play a protective role in a wide range of diseases characterized by an increased metalloproteinases (MMPs) activity. The recent finding that omega-3 and omega-6 fatty acids exert an anti-inflammatory effect in periodontal diseases has stimulated the present study, designed to determine whether such properties derive from a direct inhibitory action of these compounds on the activity of MMPs. To this issue, we investigated the effect exerted by omega-3 and omega-6 fatty acids on the activity of MMP-2 and MMP-9, two enzymes that actively participate to the destruction of the organic matrix of dentin following demineralization operated by bacteria acids. Data obtained (both in vitro and on ex-vivo teeth) reveal that omega-3 and omega-6 fatty acids inhibit the proteolytic activity of MMP-2 and MMP-9, two enzymes present in dentin. This observation is of interest since it assigns to these compounds a key role as MMPs inhibitors, and stimulates further study to better define their therapeutic potentialities in carious decay.

Dry reforming (DRM) is as an efficient way for CH 4 and CO 2 valorisation because the produced syn -gas has an H 2 /CO ratio equal to that suitable for the synthesis of oxygenated hydrocarbons and synthetic fuels. The development of Ni (10 wt%) based structured and unstructured catalysts promoted by a small amount of Ru (0.5 wt%) for DRM has been investigated. Unstructured catalysts were prepared by wet impregnation method and a combination of wash coating-wet impregnation methods was used for cordierite monoliths. Samples were characterized by XRD, BET, H 2 -TPR, TEM, FE-SEM, XPS techniques and the catalytic activity for DRM was evaluated in the temperature range 600–800 °C. The catalyst stability was followed at 800 °C during time on stream. Ru promoted catalyst (Ni-Ru) was remarkable active and stable whereas Ni catalyst deactivated due to the formation of Ni 2 + -containing inactive phases. Ni-Ru monolith was initially much more active than monometallic Ni stating the positive effect of Ru on maintaining Ni reduced. Reaching steady state condition, Ni rapidly deactivated due to carbon formation, whereas Ni-Ru monolith remained stable confirming that Ru behaves as an efficient and cheap promoter of Ni for DRM.

Prompt-gamma activation analysis (PGAA) measurements were carried out at the ISIS Spallation Neutron Source on two sets of functional commercial stainless steel orthodontic archwires, aiming at providing insights into the elemental and isotopic composition differences of two nominally equivalent archwires. The results were compared to those obtained from parallel cold neutron PGAA measurements on the same samples at the Budapest Neutron Centre in order to test the current status of PGAA at a pulsed neutron source and eventually to inform improvement in set-up and acquisition methods. In addition, time-resolved PGAA (T-PGAA) that combines PGAA and neutron time-of-flight methods was applied to the present set of samples, allowing the measurement of the neutron energy dependence of the PGAA spectra. The advantages of this technique were demonstrated to be that through incident neutron energy selection, spanning 0.07–67.94 eV, enhancement or decrease of specific gamma lines associated with isotopes of interest could be achieved. These were shown to reduce peak interference and to increase the signal-to-background ratio for certain species in order to facilitate accurate elemental identification. Suggestions for potential performance improvement for this evolving technique are proposed.

Periodic and molecular cluster models are presented for anorthite (CaAl2Si2O8), a cement forming glass with desirable thermal and mechanical properties also tested in dental applications. Both the crystalline and amorphous structures were characterised by ab initio molecular dynamics and found to be in good agreement with experiment. Additional investigations of the elongation and fracture of the glass were also made. The recovery of material properties signaled the failure of the periodic method to generate acceptable fracture surfaces to model cement forming-sites. Isolated molecular cluster models of anorthite were therefore investigated with electronic structure methods and showed sound structural matches with the traditional periodic structures. The equilibrated glass clusters were used to develop cement models, through binding of short acid oligomers to selected Al-centres, simulating the glass-polymer interface. Overall, the anorthite glass structures emerging from periodic and cluster models were in close agreement. Results suggest that bare molecular cluster models represent an alternative avenue for accurately investigating amorphous systems, providing more realistic descriptions of edge and corner sites, as well as interfaces.

Despite its large interesting as component for low melting HTF and HSM, very few thermodynamics information is available regarding calcium nitrate and its mixtures. In this paper the binaries between Ca(NO3)2 and both NaNO3 and KNO3 are experimentally investigate by DSC and Neutron scattering. The results show that the solid phase of the binaries is composed by a solid solution of single nitrates. The DSC pattern and the eutectic point were modeled by the regular solution theory and the fitting parameters are reported. © 2019 Author(s).

Pd-doped lanthanum strontium ferrite powders La0.6Sr0.4Fe1-xPdxO3-δ with x = 0.05, 0.1 (LSFPd05 and LSFPd10) are synthesized by combustion synthesis method and investigated as electrocatalysts for fuel and air electrodes of symmetric solid oxide fuel cells (SSOFCs). X-ray diffraction (XRD), Rietveld refinement, surface area (BET), temperature programmed reaction (TPR) and temperature programmed oxidation (TPO) analyses are performed on LSFPd powders. Electrical measurements both in oxidizing and reducing conditions are carried out on sintered pellets. Electrolyte (La0.8Sr0.2Ga0.8Mg0.2O3-δ) supported cells are prepared using LSFPd powders as electrodes. The electrochemical performances are evaluated in hydrogen and methane mixtures and promising performance are revealed in terms of large power output density and low polarization resistance. © 2019 Acta Materialia Inc.

In the present work, 5wt% Ni-Ce0.85Sm0.15O2-δ powders were synthesized by citrate-nitrate auto-combustion method and structured catalysts based on NiCrAl alloy foam were prepared by wash-coating technique. The open-pores of the foam enhance the heat and mass transfer. Besides, the oxygen vacancies of SDC promote the CH4 and CO2 activation for carbon suppression. Microstructural analysis of Ni-SDC/NiCrAl faom structured catalyst displayed a homogeneous distribution of the catalytic layer. Catalytic tests for DRM at 800 °C showed that the CH4 conversion was 87%, close to thermodynamic equilibrium, and the yield of H2 was 76%, indicating that the structured catalyst is suitable for indirect internal reforming in SOFCs.

Solid oxide fuel cells (SOFCs) have received considerable attention mainly for the high conversion efficiency and the capability of being powered by methane or biogas. Among the different routes for methane-syngas conversion, the dry reforming of methane (DRM) shows the combined advantages of syngas production and CO2 utilization. Besides it is extremely endothermic and it requires temperatures as high as those of operating SOFCs. Thus, SOFCs can operate in indirect internal reforming mode: simultaneously performing DRM reaction in their anode sides and, partly, compensating the energy necessary for the reforming with the heat released during the electro-oxidation. Nickel supported on samarium doped ceria (SDC) is a highly performing anodic material showing a remarkable electro-catalytic activity due to the presence of oxygen vacancies that promote the CH4 and CO2 activation for carbon suppression

Vanadium redox flow battery (VRFB) is one of the most promising large-scale energy storage system; however, a widespread VRFB development is still limited by the poor electrochemical activity of graphite electrodes and a poor understanding of redox reactions occurring at electrode/electrolyte interface. In this work, DFT was performed to study the first solvation shell structure of all vanadium ions and to investigate the reactivity of modified graphite electrodes toward the V2+/V3+ redox species. The results suggest that the presence of oxygen and nitrogen functionalities at the electrode edges provides more active sites for adsorption of the V2+/V3+ redox couple, and therefore improve electron transfer kinetics. These results have been experimentally validated by means of Cyclic Voltammetry and Electrochemical Impedance Spectroscopy with carbon black electrode having different density of oxygen and nitrogen-containing surface groups.