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Fuel flexibility is one of the main advantages of Solid Oxide Fuel Cells (SOFCs) technology and is related to the high operating temperatures (773-1273K). SOFCs can be fed by methane, higher hydrocarbons and also bio-gas produced by the anaerobic fermentation of wastes and biomass. The composition range of purified bio-gas is 60-50% of CH4 and 50-40% of CO2. Thus, in principle biogas-fueled SOFCs can be operated with internal dry reforming reaction (DMR) (equation 1) by the presence of CO2 as reforming agent [1-3]. (1) DRM is commonly used for syn-gas production, thus catalysts are specially designed for this purpose. However, being generally composed by low metal loading and support with negligible ion-conduction they are unsuitable for the use in SOFCs anodes. Therefore, development of anodes with high activity toward the dry reforming of methane is still challenging. One way may be the preparation of cermets composed by low carbon sensitive Ni based- alloys [4] and highly ion-conductive electrolytes such as GDC [5]. In particular, among the oxygen-ion conducting electrolytes La0.8Sr0.2Ga0.8Mg0.2O3- (LSGM) showed a large ionic conductivity (ca. 0.02 Scm-1 at 600 oC), although the formation of insulating secondary phases and cations interdiffusion across the interface with electrodic layers have been often observed t temperatures ≥1100 °C [6]. Thus, the implementation of such Ni-based alloys requires the preparation of LSGM scaffold to be impregnated by the active components. In this work Ni, NiCo and NiCu supported on LSGM commercial powder were prepared by a conventional wet impregnation method. The catalysts were characterized by XRD, H2-TPR, CO2-TPD, BET and SEM. The catalytic activity for the DRM was studied into a quartz tubular reactor as a function of temperature and CH4/CO2 molar ratio at high GHSV (120000mLg-1h-1) simulating the condition presents in the anodic scaffold of a anode supported LSGM based SOFCs. The catalytic activity increased in the order NiCu

Catalytic aerobic oxidation of benzyl alcohol (BnOH) to benzaldehyde (PhCHO) over supported noble metal catalysts has grabbed the attention of researchers due to the critical role of PhCHO in numerous industrial syntheses. In the present study, a novel catalyst, Pd-P alloy supported on aminopropyl-functionalized mesoporous silica (NH2-SiO2), was prepared through in situ reduction and characterized by BET-BJH analysis, SEM, TEM, XRD, FTIR, TG-DTA, and XPS. Chemical properties and catalytic performance of Pd-P/NH2-SiO2 were compared with those of Pd° nanoparticles (NPs) deposited on the same support. Over Pd-P/NH2-SiO2, the BnOH conversion to PhCHO was much higher than over Pd°/NH2-SiO2, and significantly influenced by the nature of solvent, reaching 57% in toluene at 111 °C, with 63% selectivity. Using pure oxygen as an oxidant in the same conditions, the BnOH conversion increased up to 78%, with 66% selectivity. The role of phosphorous in improving the activity may consist of the strong interaction with Pd that favours metal dispersion and lowers Pd electron density.

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.

In this study, zero-valent iron-copper (Fe-Cu) and iron-nickel (Fe-Ni) bimetals were prepared by disc milling for the dehalogenation of trichloroethylene vapors. For both Fe-Ni and Fe-Cu, three combinations in terms of percentage of secondary metal added were produced (1%, 5%, 20% by weight) and the formation of the bimetallic phase by milling was evaluated by X-ray diffraction (XRD) analysis. The disc milled bimetals were characterized by a homogenous distribution of Ni or Cu in the Fe phase and micrometric size visible from scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) analysis and by a relatively low specific surface area (0.2–0.7 m2/g) quantified by the Brunauer–Emmett–Teller (BET) method. The reactivity of the produced bimetals was evaluated by batch degradation tests of TCE in the gas phase with 1 day of reaction time. Fe-Ni bimetals have shown better performance in terms of TCE removal (57–75%) than Fe-Cu bimetals (41–55%). The similar specific surface area values found for the produced bimetals indicated that the enhancement in the dehalogenation achieved using bimetals is closely related to the induced catalysis. The obtained results suggest that ZVI-based bimetals produced by disc milling are effective in the dehalogenation of TCE vapors in partially saturated conditions.

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.

The valorization of CO2 via renewable energy sources allows one to obtain carbon-neutral fuels through its hydrogenation, like methane. In this study, Ni0.05Ce0.95O2−δ catalysts were prepared using a simple one-pot hydrothermal method yielding nanorod and nanocube particles to be used for the methanation reaction. Samples were characterized by XRD, BET, TEM, H2-TPR, and H2-TPD experiments. The catalytic activity tests revealed that the best performing catalyst was Ni0.05Ce0.95O2−δ, with nanorod morphology, which gave a CO2 conversion of 40% with a selectivity of CH4 as high as 93%, operating at 325 °C and a GHSV of 240,000 cm3 h−1 g−1. However, the lower activation energy was found for Ni0.05Ce0.95O2−δ catalysts with nanocube morphology. Furthermore, an in operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis was performed flowing CO2:H2 or CO:H2 mixture, showing that the main reaction pathway, for the CO2 methanation, is the direct hydrogenation of formate intermediate.

Intermittency of renewable energy sources can be profitably faced using efficient energy storage systems. Reversible solid oxide cells (RSOCs) able to operate with carbon-containing species are likely among the most appealing choices. Energy can be obtained by natural gas and/or biogas (SOFC mode), with useful recovery of CO2 in the exhausts. Besides, if the electrode is also active towards CO2 electrolysis (SOEC mode), CO2 is reduced to CO and O2. In this work a composite material with in-situ formed Ni-Fe alloy catalyst consisting of La1.2Sr0.8Fe0.6Mn0.4O4 Ruddlesden-Popper perovskite and Ni-Ce0.85Sm0.15O2-δ fluorite was developed as a multi-functional fuel-electrode for RSOCs. The composite electrode was tested in SOFC mode as anode for hydrogen, dry methane and carbon monoxide oxidation and showed power density outputs of 657, 668 and 527 mW/cm2 at 850 °C, respectively, together with redox stability and coking tolerance for over 120 h. In SOEC mode, it was tested as cathode and delivered 2.66 A/cm2 at 2 V in a 95:5 CO2:CO mixture, retaining a current density of 1 A/cm2 for more than 40 h.

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.

Carbon dioxide collected from outdoor atmosphere or produced in aerospace cabin, may be recycled to produce methane and water by methanation reaction (Sabatier reaction). This reaction needs a heterogeneous catalyst to decrease the reaction temperature and increase the selectivity. A proper catalyst for in-situ CO 2 recycling into methane requires: i) high CO 2 conversion with high CH 4 selectivity at low operating temperature, ii) high stability towards degradation, being required that catalyst remains highly active during the entire production process. This paper presents a preliminary study of a catalyst based on Ni supported on cerium oxide, prepared by one-pot hydrothermal method, leading to a nanorod morphology with high and uniform nickel dispersion. Morphology and chemical properties of the material were characterized by BET, H 2 -TPR, XRD and FE-SEM/EDS. The catalyst was tested in a flow system at atmospheric pressure, using reagents with stoichiometric ratio (CO 2 :H 2 =1:4) or enriched in hydrogen. The Ni/r-CeO 2 catalyst showed high stability over time on stream, in oxidizing condition and after switch off-switch on test.

Chlorinated solvents are extensively used in many activities and hence in the past decades impacted a large number of sites. The presence of these contaminants in groundwater is challenging particularly for the management of the vapor intrusion pathway. In this work we examine the potential feasibility of using horizontal permeable reactive barriers (HPRBs) placed in the unsaturated zone to treat chlorinated solvent vapors emitted from groundwater. Zero-valent iron (ZVI) powders, partially saturated with water and characterized by different specific surface areas (SSA), were tested, alone or mixed with sand, in lab-scale batch reactors using TCE as model compound. Depending on the type of iron powder used, a reduction of TCE concentration in the vapor phase from approximately 35% up to 99% was observed after 3 weeks of treatment. The best performance in terms of TCE reduction was obtained using the ZVI characterized by the intermediated values of the specific surface area (SSA). This finding, which is in contrast with the results generally observed in in aqueous solutions, was tentatively attributed to a non-selective higher reactivity of the fine-grained iron samples with water and dissolved oxygen (with a consequent iron passivation) or to the occurrence of a diffusion-limited reaction kinetics. Based on the first-order kinetic degradation rate constants estimated from the experimental data, a horizontal barrier of 1 m containing ZVI or a mixture of ZVI and sand can potentially lead to an attenuation of TCE vapors over 99%.

In the attempt of satisfying the quest for new antifouling products tailored for applications on Cultural Heritage, we have synthesized and characterized two different silica nanosystems. The first consists of core-shell nanocapsules and the second one of mesostructured nanoparticles. Both systems have been successfully loaded in situ with the commercial biocide 2-mercaptobenzothizole (MBT). The synthesis procedure and particles characterization measurements, as far as their dimensions and superficial properties, loading capability, and release rate in aqueous solution, are reported. We stress that both particles have the dimensions required to avoid undesired light scattering once dispersed on the artefact surface. Interestingly, the two nanoparticles have complementary properties, suggesting that combining them in a coating may have a higher potential for production of new generation active products.

Ni-based oxides are widely investigated as catalysts for CO2 methanation due to their high activity, high selectivity and low cost. The catalytic performances of Ni-based catalysts depend on support properties that strongly influence the dispersion of the catalytic active phase and the Ni&ndash, support interaction. Although the CO2 methanation is widely studied, the structure sensitivity of methanation on nickel is not completely assessed. Ni/CeO2 nanorods with different nickel/ceria molar ratios (0.05, 0.10, 0.20, 0.30) were prepared by one-pot hydrothermal synthesis. The effect of nickel content and metal particle size on catalytic activity and selectivity for CO2 methanation were studied using CO2:H2 = 1:4 stoichiometric ratio at high space velocity (300 L g&minus, 1 h&minus, 1). Sample structure and morphology were studied by X-ray diffraction (XRD), Brunauer&ndash, Emmet&ndash, Teller (BET) analysis, field-emission scanning electron microscopy/energy-dispersive spectroscopy (FE-SEM/EDS), H2-temperature programmed reduction (TPR), H2-temperature-programmed desorption (TPD). Both the CO production and the turnover frequency appear depending on nickel particle size, suggesting a structure sensitivity of the CO2 methanation on nickel supported on ceria.

In in-situ resource utilization and in atmosphere revitalization processes, CO 2 may be recycled to produce methane and water by Sabatier reaction. The traditional Ni/γ-Al 2 O 3 catalyst for Sabatier reaction was modified by addition of rare earth oxides La 2 O 3 and/or CeO 2 in order to improve activity, selectivity and stability. Preliminary results showed that La addition improved activity and CH 4 selectivity against CO more than Ce addition. Catalytic activity was tested using stoichiometric flow (CO 2 :H 2 = 1:4) without dilution.

Cycling high temperature CO2 capture using CaO&ndash, based solid sorbents, known as the calcium looping (CaL) process, is gaining considerable scientific and industrial interest due to the high theoretical sorbent capacity (0.78 gCO2/gCaO), the low specific cost, and the negligible environmental impact of the employed materials. In this work, we investigated the self&ndash, combustion synthesis of CaO&ndash, CaZrO3 sorbents with different CaO contents (40, 60, and 80 wt%) for use in the CaL process. CaZrO3 was used as a spacer to avoid CaO grains sintering at high temperature and to reduce the diffusional resistances of CO2 migrating towards the inner grains of the synthetic sorbent. Samples were characterized by X&ndash, ray diffraction (XRD), Brunauer&ndash, Emmett&ndash, Teller (BET), and scanning electron microscopy (SEM) analyses. The reaction between CO2 and CaO (i.e., carbonation) was carried out in 20 vol% CO2 at 650 &deg, C and calcination (i.e., decomposition of CaCO3 to CaO and CO2) at 900 &deg, C in pure Ar or with 85 vol% CO2 using a thermogravimetric analyzer (thermogravimetric/differential thermal analysis (TG&ndash, DTA)). The most stable sorbent was with 40 wt% of CaO showing a CO2 uptake of up to 0.31 g CO2/gsorbent and 0.26 g CO2/gsorbent operating under mild and severe conditions, respectively. The experimental data corroborated the prediction of the shrinking core spherical model in the first phase of the carbonation. A maximum reaction rate of 0.12&ndash, 0.13 min-1 was evaluated in the first cycle under mild and severe conditions of regeneration.

The paper shows a comparison between three routing protocols for WSN. The protocols are conceived for particular scenario easily findable in archeological site and take into account energy consumptions and robustness of the transmission. This study will show which of the three protocols better meets the needs of this particular scenario.

This paper describes an E-Nose aimed to Pesticide Detection which uses an array of different commercial gas sensors. In order to optimize the array reducing the redundancies due to similar sensors answers, Wilks' A-statistic has been used.

Selective oxidation of benzyl alcohol (BA) to benzaldehyde (BZ) is considered as a crucial functional group transformation, since the product is a key intermediate for the synthesis of fine chemicals, in the perfume, pharmaceutical and dyestuff industries. This oxidation reaction is conventionally performed by various stoichiometric oxygen donors such as chromates, permanganates, and peroxides which are expensive and highly toxic. Therefore, from environmental point of view, and to reduce the overall production cost, there is a great interest in the development of heterogeneous catalysts capable of utilizing air or O2 as greener oxidants. Supported noble-metal catalysts has been investigated in numerous studies and showed promising potential to carry out selective oxidation of BA to BZ; however, various issues such as catalyst deactivation and BZ selectivity must be overcome for the industrial implementation of this reaction. In this research work, the selective oxidation of BA to BZ was studied using Palladium supported on CeO2 Nanorods (NR) as catalyst, and atmospheric air as greener oxidant. CeO2-NR were prepared according to previously published hydrothermal method [10]. Palladium oxide was deposited by wet-impregnation on CeO2-NR using Pd(NO3)2 • 2H2O and calcination at 400 °C (PdO/CeO2-NR). The effect of oxidation state of palladium on the catalytic activity was also investigated by using the reduced form of the catalyst (Pd/CeO2-NR-H2). Structural, morphological and redox properties of the synthetized materials were studied by mean of XRD, TEM, SEM, TPR and BET methods. Catalytic oxidation of benzyl alcohol using PdO/CeO2-NR or Pd/ CeO2-NR-H2 was conducted in toluene and in ethanol solvents under air flow (20ml/min). Effect of temperature (60-110 °C), BA concentration and catalyst/BA ratio (1/1, 2/1, 3/1) on catalytic activity and BZ yield was studied. Reactant and products were analyzed by GC-MS. The results showed that in toluene, catalyst deactivation occurred and high BZ yield was not achieved. In ethanol as solvent, BZ was produced with up to 99% yield and considerable selectivity. The oxidation rate increased with the catalyst/substrate ratio and with the BA concentration.

this paper is a section of several preliminary studies versus the realization of Underwater Drones of the Universita degli Studi "Roma Tre" Science Department: we describe an application of Takagi-Sugeno fuzzy logic modelling to the longitudinal control for the underwater glider in order to simplify the calculation effort.

In the present study, the catalytic activity of palladium oxide (PdOx) supported on ceria nanorods (CeO2-NR) for aerobic selective oxidation of benzyl alcohol (BnOH) to benzaldehyde (PhCHO) was evaluated. The CeO2-NR was synthesized hydrothermally and the Pd(NO3)2 was deposited by a wet impregnation method, followed by calcination to acquire PdOx/CeO2-NR. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), transmission electron microscopy (TEM), Brunauer&ndash, Emmet&ndash, Teller (BET) surface area analysis, and X-ray photoelectron spectroscopy (XPS). In addition, the TPR-reduced PdOx/CeO2-NR (PdOx/CeO2-NR-Red) was studied by XRD, BET, and XPS. Characterizations showed the formation of CeO2-NR with (111) exposed plane and relatively high BET surface area. PdOx (x &gt, 1) was detected to be the major oxide species on the PdOx/CeO2-NR. The activities of the catalysts in BnOH oxidation were evaluated using air, as an environmentally friendly oxidant, and various solvents. Effects of temperature and palladium oxidation state were investigated. The PdOx/CeO2-NR showed remarkable activity when protic solvents were utilized. The best result was achieved using PdOx/CeO2-NR and boiling ethanol as solvent, leading to 93% BnOH conversion and 96% selectivity toward PhCHO. A mechanistic hypothesis for BnOH oxidation with PdOx/CeO2-NR in ethanol is presented.