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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.

CO2 collected from the outdoor atmosphere or produced in an aerospace cabin, may be recycled to produce methane and water by the Sabatier reaction. This reaction is carried out over a catalyst to decrease the reaction temperature and increase the selectivity towards CH4 avoiding CO production. The practice of “in-situ resource utilization” needs a catalyst highly active at low temperatures, highly selective, and stable towards deactivation throughout the duration of the mission. This paper reports the catalytic activity of CeO2 supporting ruthenium (3 wt%), synthesized by the one-pot hydrothermal method followed by a reduction in H2 at 500 °C. Catalyst morphology and Ru reducibility and dispersion were investigated by XRD, FE-SEM-EDS microscopy, BET, H2-TPR and H2-TPD. The catalytic properties for the CO2 methanation were tested at atmospheric pressure with a stoichiometric ratio of the reagents (CO2: H2 = 1: 4). The one-pot synthesis of Ru(3wt%)/CeO2 produced an unexpected nanocube morphology with a high surface area, favouring a very high Ru dispersion (50%) corresponding to an average particle dimension < 2 nm. The catalyst shows good catalytic performances reaching 70% of CO2 conversion at 350 °C, with 98% of selectivity towards CH4. Carrying out the reaction for 12 hours at 500 °C, the catalyst shows no activity nor selectivity loss, appearing as a reliable catalyst for in-situ resource utilization and atmosphere revitalization processes

Selective oxidation of benzylic alcohols is a crucial reaction in organic syntheses because the products, such as aldehydes and ketones, play important roles in numerous industries. Noble metals have been proved to be able to effectively catalyze this reaction in relatively green conditions. In the present research, solvent-free aerobic oxidation of several benzylic alcohols catalyzed by palladium oxide supported on ceria nanorods (PdOx/CeO2-NR) is investigated. The Ceria nanorods (CeO2-NR) were prepared by a hydrothermal process, and calcination. Pd(NO3)2 was deposited on the CeO2-NR by a wet impregnation process at mild conditions and the resulting PdOx/CeO2-NR catalyst was prepared by calcination at 500 °C. The prepared material was fully characterized (XRD, SEM, BET, XPS). Solvent-free aerobic oxidations of benzyl alcohol derivatives were performed using this PdOx/CeO2-NR . The results of the reactions were studied by GC-MS. Presence of electron-donating groups on benzyl alcohol aromatic ring led to an increase in the conversion even if with a decrease in selectivity while substitution of electron-withdrawing groups resulted in drastic lowering of the catalytic activity. A mechanistic explanation will be presented.

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.

Summary Within a project co-funded by the Italian Ministry of Foreign Affairs, the final aim of which is to develop a WSN for smart monitoring of pesticides on agricultural land, the Italian and Serbian researchers have developed a hardware section of an electronic nose for pesticides. Since there are no specialized sensors which can smell the presence or absence of pesticides in the air, the electronic nose has been designed starting from an array of commercial gas sensors developed for other environmental applications. These sensors have a great advantage as they are COTS components. A measurement bench for testing the performance of the system has also been developed. Experimental tests have been conducted and the results have demonstrated the appropriateness of the idea. A test for calibration has been designed, as well, and it will be performed in the near future.

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.

Ni/ZrO2 catalysts, active and selective for the catalytic partial oxidation of methane to syngas (CH4-CPO), were prepared by the dry impregnation of zirconium oxyhydroxide (Zhy) or monoclinic ZrO2 (Zm), calcination at 1173 K and activation by different procedures: oxidation-reduction (ox-red) or direct reduction (red). The characterization included XRD, FESEM, in situ FTIR and Raman spectroscopies, TPR, and specific surface area measurements. Catalytic activity experiments were carried out in a flow apparatus with a mixture of CH4:O2 = 2:1 in a short contact time. Compared to Zm, Zhy favoured the formation of smaller NiO particles, implying a higher number of Ni sites strongly interacting with the support. In all the activated Ni/ZrO2 catalysts, the Ni–ZrO2 interaction was strong enough to limit Ni aggregation during the catalytic runs. The catalytic activity depended on the activation procedures, the ox-red treatment yielded very active and stable catalysts, whereas the red treatment yielded catalysts with oscillating activity, ascribed to the formation of Niδ+ carbide-like species. The results suggested that Ni dispersion was not the main factor affecting the activity, and that active sites for CH4-CPO could be Ni species at the boundary of the metal particles in a specific configuration and nuclearity.

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%.

The catalytic conversion of carbon dioxide to synthetic CH4 was studied on five Ni/YSZ samples, with the same nickel loading (10 wt%) but different Ni particle size. The catalysts, prepared by different methods, were characterized combining morphological (BET, TEM), structural (XRD, in-operando XAS), electronic (XPS, in-operando XANES) analysis and H2-TPR experiments. The results showed that catalytic activity and CH4 selectivity depended on size and morphology of Ni particles, and that type and amount of deposited carbon strongly depended on Ni0 morphology. The kinetic measurements revealed that both H2 and CO2 reactants were activated on Ni sites, and that YSZ support was not directly involved in the reaction mechanism. The most efficient catalyst was that prepared by wet impregnation with Ni(EDTA)2− complex due to the high Ni0 dispersion.This catalyst showed low amount of carbon and remarkable stability over time on stream. In-operando XAS showed that it did not undergo deactivation by Ni0 → Ni2+ oxidation using high CO2 concentration, thus it is applicable in dynamic conditions like those typical in the energy storage from renewable sources process.

Reversible solid oxide cells (RSOCs) represent a promising technology for the efficient exploitation of intrinsically intermittent renewable energy sources. RSOCs allow to derive fuel and chemicals from power (power-to-gas technology, P2G) and power from fuel and chemicals (gas-to-power technology, GTP) and can be interchangeably operated either as a solid oxide fuel cell (SOFC) or as a solid oxide electrolyzer cell (SOEC). The key aspect to render these devices competitive on a market scale is the development of multi-tasking, reliable, cost-effective and long-lasting electrodes (1,2). Besides, to overcome the issues related to hydrogen production, storage and distribution (e.g. impractical conversion of the existing grid to hydrogen-based infrastructures), the fuel-electrode of RSOCs should ensure high catalytic activity and coking resistance toward carbon-containing species (3-4). Using a hydrocarbon-tolerant fuel electrode, energy can be obtained by natural gas and biogas (SOFC-mode), with useful recovery of CO2 in the exhausts (carbon capture and storage, CCS). Besides, if the electrode is also active towards CO2 electrolysis (SOEC mode), CO2 is reduced to CO and O2 (carbon capture and utilization, CCU). Ni-YSZ is the reference fuel-electrode material for both H2 fed SOFC and for CO2 electrolysis in SOEC. Nevertheless, Ni-based cermets cannot be used in SOFCs fed with methane-containing fuels, as they suffer from two main drawbacks: mechanical instability upon NiO-Ni redox cycles (5) and passivation due to coking, being Ni a catalyst for methane cracking (3, 4). Moreover, during Ni-YSZ operation in CO2-SOEC mode, ZrO2 reduction can occur at high cathodic potential, resulting in Ni-Zr compounds formation (6). In this work, a recently developed (7, 8) composite material containing La0.6Sr0.4Fe0.8Mn0.2O3-δ (LSFMn) and 5wt% Ni-containing Ce0.58Sm0.15O2-δ (NiSDC) is tested as fuel electrode for LSGM-electrolyte supported cells. In reducing conditions, Fe exsolved from the LSFMn perovskite forms a Fe-Ni alloy with Ni present on SDC. In SOFC mode, the composite is designed to operate in dry methane: Fe-Ni catalytic sites activate CH4, which is successively oxidized on Mn-containing LSFMn, while SDC increases the O2- supply at the anode to get rid of any carbonaceous deposits. As Fe-Ni alloy was reported to be highly active for CO2 reduction (9), the composite was also tested as SOEC cathode in different CO2:CO ratios. LSFMn+NiSDC 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, respectively (Fig. a), a redox stable behavior and coking resistance for over 120 h. LSFMn+NiSDC in SOEC-mode delivered 2.66 A/cm2 at 2 V in 95:5 CO2:CO mixture (Fig. b), keeping 1 A/cm2 of current density output for over 40 h. (1) - M. Mogensen, M. Chen, H. Frandsen, C. Graves, J. Hansen, K. Hansen, A. Hauch, T. Jacobsen, S. Jensen, T. Skafte, Reversible solid-oxide cells for clean and sustainable energy, Clean Energy, 3 (2019) 175-201. (2) - M.B. Mogensen, Materials for Reversible Solid Oxide Cells, Current Opinion in Electrochemistry, (2020). (3) - M. Mogensen, K. Kammer, Conversion of hydrocarbons in solid oxide fuel cells, Annual Review of Materials Research, 33 (2003) 321-331. (4) - S. McIntosh, R.J. Gorte, Direct hydrocarbon solid oxide fuel cells, Chemical reviews, 104 (2004) 4845-4866. (5) - J. Malzbender, R. Steinbrech, Advanced measurement techniques to characterize thermo-mechanical aspects of solid oxide fuel cells, Journal of Power Sources, 173 (2007) 60-67 (6) - A. Hauch, K. Brodersen, M. Chen, M.B. Mogensen, Ni/YSZ electrodes structures optimized for increased electrolysis performance and durability, Solid State Ionics, 293 (2016) 27-36 (7) - L. Duranti, I. Luisetto, S. Licoccia, C. Del Gaudio, E. Di Bartolomeo, Electrochemical performance and stability of LSFMn+ NiSDC anode in dry methane, Electrochimica Acta, (2020) 137116. (8) - L. Duranti, I.N. Sora, F. Zurlo, I. Luisetto, S. Licoccia, E. Di Bartolomeo, The role of manganese substitution on the redox behavior of La0.6Sr0.4Fe0.8Mn0.2O3-δ, Journal of the European Ceramic Society, (2020) ( 9 ) - Liu, S., Liu, Q., & Luo, J. L. (2016). Highly stable and efficient catalyst with in situ exsolved Fe–Ni alloy nanospheres socketed on an oxygen deficient perovskite for direct CO2 electrolysis. ACS Catalysis, 6(9), 6219-6228. Figure 1

Ni supported on yttrium-stabilized zirconium oxide catalysts have been prepared by electroless plating method. Structure, electronic and chemical state of Ni as a function of Ni content (1, 7 and 12 wt%) have been characterized combining X-ray diffraction, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction (H2-TPR) and BET. The catalytic activity for the CO2 methanation was studied in the 250–500 °C temperature range, finding the highest CO2 conversion and CH4 selectivity for the catalyst with the largest Ni loading. A dependence of activity and CH4 selectivity on Ni crystallites size was highlighted.

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.

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 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.

Carbon dioxide is the principal greenhouse gas produced by fossil fuels combustion. The CO2 methanation (Sabatier reaction) CO2 + 4H2 → CH4 + 2H2O combines the valorisation of CO2 with the storage of surplus energy by renewable sources (solar, wind), in the power to gas process (PtG). The present work uses ceria nanorods as support for metallic nickel. The Ce1-xNixO2-δ catalysts with different nickel content (x = 0.05; 0.10; 0.20; 0.30) were prepared by hydrothermal synthesis. Catalysts have been characterized by XRD, BET, H2-TPR, H2-TPD, FESEM, with the aim to verify the structure–sensitivity of the methanation on nickel. The catalytic activity and selectivity were studied using different CO2:H2 molar ratios, under atmospheric pressure, in the temperature range 200–500°C and gas hourly space velocity (GHSV) 300.000 cm3 h-1 g-1. The stability tests were performed at 400°C and GHSV 300.000 cm3 h-1 g-1 under fluctuating reaction conditions.

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

The role of dopants on the catalytic activity for the dry reforming of methane (DRM) was investigated on nickel supported on metal doped ceria (Me-DC) catalysts, Ni/Me0.15Ce0.85O2-δ with Me = Zr4+, La3+ or Sm3+, prepared by citric acid synthetic route. The catalytic activity was in the order Ni/Zr-DC Zr-DC > CeO2. The extra oxygen vacancies introduced by La3+ and Sm3+ were not capable to split CO2. La-DC and Sm-DC showed significant differences in the numbers and strength of surface basic sites. Therefore, other phenomena rule the formation/removal of carbon on these catalysts. The nature of dopants influenced the Ni-supports interaction and the electronic state of the metal catalyst.

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.

Although some recent developments in nanotechnology made the prospects of a direct mechanical manipulation of micro- or nano-objects quite realistic, there are still several concerns and difficulties that affect such an endeavor. This is probably due to the large base of knowledge that is necessary to approach the problem of handling a nano-object by means of a nano- or micro-device. Therefore, any progress in this field is possible only by means of an integrated and interdisciplinary approach, which takes into account different aspects of the phenomenon. During the actual pioneering phase, there is a certain convenience in handling nano-objects that: (a) have peculiar known characteristics, (b) are easily recognizable, and (c) are interesting to the scientific community. This paper presents the interdisciplinary activities that were necessary to set up an experiment where specifically synthesized SiO2 particles came in contact with the tips of specifically-designed and -fabricated nanomanipulators. SiO2 mesoporous nanoparticles (KCC-1), having a peculiar dendritic structure, have been selected as a suitable nano-object because of the possibility to easily modulate their morphology. The expected contact force has been also calculated by means of Finite Element Analysis (FEA) electro-mechanical simulations.

The Dry reforming of methane (DRM) is as an efficient way for CH4 and CO2 valorisation because the produced syn-gas has an H2/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%) 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. Ru promoted catalyst (Ni–Ru) was remarkable active showing higher reactant conversions and H2/CO ratio compared with Ni catalyst. 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.

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.

Production of propellant for the return to Earth from in-situ resources allows not transporting the return fuel in space explorations. CO 2 from Martian atmosphere may react with H2 to produce methane and water by Sabatier reaction. The activity of Ni (10 wt%) supported on Y 2 O 3 -ZrO 2 , by different preparation methods, was compared. Structural characterization by XRD, TPR and TEM, evidenced that catalytic performances for CO 2 methanation mainly depended on the Ni°particle size and morphology. In particular, the catalyst prepared by wet impregnation with Ni(EDTA)−2 complex, having high nickel dispersion and strong Ni-support interaction, showed remarkable activity, selectivity and stability over time on stream using stoichiometric flow (CO 2 :H 2 = 1:4), appearing like a reliable catalyst for Sabatier process.

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.

Composite anodes containing La0.6Sr0.4CrO3-δ (LSCr) and Ce0.9Gd0.1O2 (GDC) infiltrated with 5 or 10 wt% Ni were investigated as potential catalysts for dry reforming of methane (DRM) reaction in methane rich mixtures. Powders were characterized and tested as catalysts for DRM reaction. Ni-infiltrated composite anodes were used for fuel cell tests and compared to Ni-free anodes. Electrochemical tests were performed in different gas mixtures to evaluate the anodic performance in externally reformed biogas (external reforming mode). The design of an external layer of composite anode achieved the internal DMR reaction (internal reforming mode).

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.

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.

La0.8Sr0.2Ga0.8Mg0.2O3- d (LSGM) based porous/dense structures were optimized for infiltration of different metal catalysts. A solution of metal (Ni, Co, Cu and their 1:1 mixtures) salts was used for infiltration. Multiple infiltrations were necessary to get enough metal catalyst amount to get performing electrocatalytic performance. For the initial catalyst screening, ex-situ catalyst activity measurements were performed on impregnated LSGM powders with the same amount of metal catalyst infiltrated in the scaffolds. Electrochemical measurements were performed on infiltrated cells with the same amount of Ni and Ni-Co in the temperature range between 650 and 750°C and the results discussed and compared with catalytic measurements.

The Dry reforming of methane (DRM) is as an efficient way for CH4 and CO2 valorisation because the produced syn-gas has an H2/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%) 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. Ru promoted catalyst (Ni-Ru) was remarkable active showing higher reactant conversions and H2/CO ratio compared with Ni catalyst. 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.

A comparison of CoNi-CeO2 bimetallic catalyst with Co-CeO2 and Ni-CeO2 monometallic catalysts for the dry reforming of methane (DRM) was carried out in order to highlight the effect of Co on activity and on catalyst deactivation due to carbon deposition. Catalysts were characterized by temperature programmed reduction techniques using in situ XRD (TPR-XRD), in situ XAS (TPR-XAS) and HR-TEM. Ni-CeO2 monometallic catalyst was active but formed a large amount of deposited carbon. The CoNi-CeO2 bimetallic catalyst showed comparable performance without carbon deposit, whereas Co-CeO2 showed poorer performance. Kinetic analysis of the CH4 consumption rate versus the reactant partial pressure suggested that Co addition enhance the carbon oxidation by a redox mechanism involving Co+/Co0 species, increasing the catalyst stability.

A series of Ni (10 wt %) supported on commercial yttrium stabilized zirconia (YSZ) catalysts have been prepared by different methods to evaluate the effect of Ni0 particle size on CO2 methanation activity. The reducibility and metal-support interaction were analyzed by H2-temperature programmed reduction (TPR) and in-situ x-ray absorption spectroscopy (XAS). The particle size and morphology were analyzed by TEM. A correlation of the catalytic activity with Ni0 particle size and metal-support interaction was found. The catalyst stability during time of stream (TOS) and under CO2 stream was performed by in-situ XAS. Apparent activation energy and reaction orders are determined for the most performing catalyst.