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6 figures, 3 tables., Perfluorinated sulfonic acid (PFSA) polymers such as Nafion® are widely used for both electrolyte membranes and ionomers in the catalytic layer of membrane-electrode assemblies (MEAs) because of their high protonic conductivity, σH, as well as chemical and thermal stability. The use of PFSA polymers with shorter side chains and lower equivalent weight (EW) than Nafion®, such as Aquivion® PFSA ionomers, is a valid approach to improve fuel cell performance and stability under drastic operative conditions such as those related to automotive applications. In this context, it is necessary to optimize the composition of the catalytic ink, according to the different ionomer characteristics. In this work, the influence of the ionomer amount in the catalytic layer was studied, considering the dispersing agent used to prepare the electrode (water or ethanol). Electrochemical studies were carried out in a single cell in the presence of H2-air, at intermediate temperatures (80–95 °C), low pressure, and reduced humidity ((50% RH). %). The best fuel cell performance was found for 26 wt.% Aquivion® at the electrodes using ethanol for the ink preparation, associated to a maximum catalyst utilization., This research was funded by the European Union’s Seventh Framework Programme (FP7/2007–2013) for Fuel Cell and Hydrogen Joint Technology Initiative under Grant no 303452 (IMPACT).

7 Figures, 2 Tables.-- This article also appears in: Giornate dell’Elettrochimica Italiana (GEI 2019)., Transition‐metal‐based materials are among the most active and durable catalysts for the effective electrocatalysis of oxygen‐related reactions. Herein, we present a study on bifunctional catalysts as air electrodes aimed at metal‐air batteries based on nickel and cobalt spinel (NiCo2O4) supported on electrospun carbon nanofibers. The physicochemical features of these transition‐metal‐based catalysts are essential for the understanding of their electrochemical activity. Results show that the major presence of oxidized Ni and Co species (Ni3+ and Co3+) produces higher activity for the oxygen evolution reaction (OER), whereas lower oxidation states of the metals (Ni2+, Co2+, Ni0 and Co0) together with the presence of N‐doped carbon lead to enhanced oxygen reduction reaction (ORR) performance. This study highlights the importance of designing catalysts in terms of crystallographic structure and proper oxidation states of the elements for maximizing their performance., The research leading to these results has received funding from the “Accordo di Programma CNR‐MiSE, Gruppo tematico Sistema Elettrico Nazionale e Progetto: Sistemi elettrochimici per l′accumulo di energia”.

9 figures, 4 tables.-- Supplementary information available.-- © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/, Iron-based aqueous batteries, such as the iron-air and nickel-iron chemistries, are limited by passivation and hydrogen evolution at the iron anode, especially at high current densities. In this paper, strategies to minimise these issues are investigated with iron electrodes composed of 20–50 nm Fe2O3 nanoparticles produced by the Adams and Oxalate methods. The strategies include ball milling the Fe2O3 with Ketjenblack carbon to improve conductivity, addition of bismuth sulphide to the electrode and 1-octanethiol to the electrolyte, and addition of potassium carbonate as a pore-forming agent. The ratio of Fe/C in the electrode and the 1-octanethiol additive have the greatest impact on the electrode capacity. The Fe/C ratio should be below 2.0 to ensure conductivity of the discharged electrode. The presence of 1-octanethiol can protect the electrodes from passivation during discharge; at very high 2C discharge rates adding 1-octanethiol increases the electrode specific capacity from 17 to 171 mAh/gFe. The synthesis method and use of pore former do not have a significant effect on the capacity. In all electrodes, the Fe2O3 nanoparticles are in the same crystalline phase after cycling and do not undergo significant crystal growth and passivation, demonstrating the stability and suitability of these materials for iron-based batteries., This work was enabled by an EU grant FP7 (NECOBAUT grant agreement no. 314159). H.A.F-R. acknowledges financial support from CONACYT, Mexico. CNR-ITAE authors acknowledge funding from the “Accordo di Programma CNR-MiSE, Gruppo tematico Sistema Elettrico Nazionale – Progetto: Sistemi elettrochimici per l'accumulo di energia”. C.A. thanks the Short-Term Mobility project of CNR.

A composite cermet consisting in a Ni–Fe alloy and Ce0.9Gd0.1O2-x (CGO) was prepared and used as an electrocatalytic pre-layer in a conventional solid oxide electrolyser (SOEC) for the co-electrolysis of H2O and CO2. The electrocatalyst showed two main phases ascribed to trevorite (NiFe2O4, 78 wt %) and metallic Ni (22 wt %) and an average crystallite size of 27 nm. The role of the Ni–Fe electrocatalyst in promoting CH4 formation was analysed by comparing gas-chromatographic and electrochemical results obtained for coated and bare cells. A slight increase of series resistance was observed for the coated cell (0.85 vs 0.53 Ω cm2) at 525 °C. However, the coated cell demonstrated an enhanced CH4 production in the entire temperature range investigated (525–800 °C). Contrarily to what observed for the bare cell which mainly produced syngas, the coated cell allowed to achieve a high yield of methane (between 67% at 525 °C and 35% at 800 °C) with selectivity to CH4 between 94% at 525 °C and 51% at 800 °C. The selectivity to CO for the coated cell was relatively low (between 6% at 525 °C and 48% at 800 °C). Whereas, the bare cell showed 98–100% selectivity to CO along the entire temperature range). Durability studies showed the possible occurrence of delamination issues as consequence of carbon formation at the interface between the supporting cathode and the electrolyte as observed from the morphological analysis of SOEC cells after operation.

In this work, we explored a scale-up procedure to non-commercially available or expensive dialkyl carbonates via transcarbonylation reaction of an alcohol with dimethyl carbonate promoted by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). DACs selected for this study include symmetrical and unsymmetrical compounds incorporating alkyl, alkoxyalkyl, aminoalkyl, and thioalkyl moieties. Compared to previously published works, the proposed procedure was customized for large-scale production of DACs (up to 100 mL); purification of the products was achieved by distillation, and recycling of the exceeding reagents was addressed. Furthermore, the role of the catalyst was investigated, and a possible reaction mechanism proposed. The chemical-physical properties of the new DACs were evaluated employing softwares and models based on quantitative structure-activity relationships (QSAR). Biodegradability and toxicity tests have also been carried out both experimentally and by computational studies so to investigate the effect of the sulfur, nitrogen, or oxygen-containing moieties on the greenness of these – in some cases new –solvents and reagents. In this work, we explored a scale-up procedure to non-commercially available or expensive dialkyl carbonates via transcarbonylation reaction of an alcohol with dimethyl carbonate promoted by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). DACs selected for this study include symmetrical and unsymmetrical compounds incorporating alkyl, alkoxyalkyl, aminoalkyl, and thioalkyl moieties. Compared to previously published works, the proposed procedure was customized for large-scale production of DACs (up to 100 mL); purification of the products was achieved by distillation, and recycling of the exceeding reagents was addressed. Furthermore, the role of the catalyst was investigated, and a possible reaction mechanism proposed. The chemical-physical properties of the new DACs were evaluated employing softwares and models based on quantitative structure-activity relationships (QSAR). Biodegradability and toxicity tests have also been carried out both experimentally and by computational studies so to investigate the effect of the sulfur, nitrogen, or oxygen-containing moieties on the greenness of these – in some cases new –solvents and reagents.

Homemade non-critical raw materials such as Ni or NiCu co-catalysts were added at the photocathode of a tandem cell, constituted by photoelectrodes made of earth-abundant materials, to generate green solar hydrogen from photoelectrochemical water splitting. Oxygen evolving at the Ti-and-P-doped hematite/TCO-based photoanode and hydrogen at the cupric oxide/GDL-based photocathode are separated by an anion exchange polymer electrolyte membrane placed between them. The effect of the aforementioned co-catalysts was studied in a complete PEC cell in the presence of the ionomer dispersion and the anionic membrane to evaluate their impact under practical conditions. Notably, different amounts of Ni or NiCu co-catalysts were used to improve the hydrogen evolution reaction (HER) kinetics and the overall solar-to-hydrogen (STH) efficiency of the photoelectrochemical cells. At −0.6 V, in the bias-assisted region, the photocurrent density reaches about 2 mA cm−2 for a cell with 12 µg cm−2 of Ni loading, followed by 1.75 mA cm−2 for the cell configuration based on 8 µg cm−2 of NiCu. For the best-performing cell, enthalpy efficiency at −0.4 V reaches a first maximum value of 2.03%. In contrast, the throughput efficiency, which is a ratio between the power output and the total power input (solar + electric) provided by an external source, calculated at −1.225 V, reaches a maximum of 10.75%. This value is approximately three times higher than the best results obtained in our previous studies without the use of co-catalysts at the photocathode. The authors gratefully acknowledge funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 760930 (FotoH2 project).

4 figures, It has recently been established that 1-octanethiol in the electrolyte can allow iron electrodes to be discharged at higher rates. However, the effect of thiol additives on the air electrode has not yet been studied. The effect of solvated thiols on the surface positive electrode reaction is of prime importance if these are to be used in an iron-air battery. This work shows that the air-electrode catalyst is poisoned by the presence of octanethiol, with the oxygen reduction overpotential at the air electrode increasing with time of exposure to the solution and increased 1-octanethiol concentration in the range 0–0.1 mol dm−3. Post-mortem XPS analyses were performed over the used air electrodes suggesting the adsorption of sulphur species over the catalyst surface, reducing its performance. Therefore, although sulphur-based additives may be suitable for nickel-iron batteries, they are not recommended for iron-air batteries except in concentrations well below 10 × 10−3 mol dm−3., This work was enabled by an EU grant FP7 (NECOBAUT grant agreement no. 314159). H.A.F-R. acknowledges financial support from CONACYT, Mexico. CNR-ITAE authors acknowledge funding from the “Accordo di Programma CNR-MiSE, Gruppo tematico Sistema Elettrico Nazionale – Progetto: Sistemi elettrochimici per l’accumulo di energia”. C.A. thanks the Short-Term Mobility project of CNR and for her Juan de la Cierva contract (FJCI-2015-25560). The authors also acknowledge financial support given by Aragon Government to the Fuel Conversion Group (T06_17R).

9 figures, 3 tables; © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, In the present work, an iron-cobaltite spinel supported on N-containing carbon nanofibers (CNFs) shows a remarkable activity for the oxygen evolution reaction (OER) in alkaline solution, with an overpotential (η10mAcm-2) of 130 mV, one of the lowest values in literature so far. This material is also an excellent catalyst for the oxygen reduction reaction (ORR), what leads to an extraordinary reversible behavior (ΔE = EOER – EORR=480 mV), being an economic and easy scalable candidate for the air electrode of metal-air batteries or for electrochemical devices where the oxygen evolution or the oxygen reduction is involved. In the present research, Fe partially replaces Co atoms in the Co3O4 spinel structure to obtain a more economically feasible material, leading to a FeCo2O4/CNF, by using an electrospinning preparation procedure previously adopted for the Co3O4/CNF synthesis. The substitution of iron in the Co3O4/CNF spinel entails an outstanding onset potential toward the OER of 1.36 V vs. reversible hydrogen electrode, which is 120 mV lower compared with the pure spinel (Co3O4/CNF). An optimal distribution of the FeCo2O4 particles on the CNF surface, with 3-nm-size particles, allows exposing abundant active sites, mainly Co3+ and Fe3+, responsible for the enhanced activity toward the OER, and Fe-Nx moieties and N-sites (N-graphitic/pyridinic), more active for the ORR. Besides, FeCo2O4/CNF shows a well-developed porous structure, favoring the mass transfer, a parameter particularly important for the ORR. To assess the stability of the catalysts for rechargeable alkaline metal-air batteries, cycling operation and chronopotentiometric experiments are carried out, showing a stable potential for 24 h., The research leading to these results has received funding from the ‘Accordo di Programma CNR-MiSE, RdS PTR 2019–2021 - Progetto 1.2 Sistemi di accumulo, compresi elettrochimico e power to gas, e relative interfacce con le reti’. C.A. thanks the Ministry of Economy, Industry and Competitiveness for her research contract Juan de la Cierva (IJCI-2017-32354).

4 figures, 1 table., In order to decrease the cost of direct methanol fuel cells (DMFCs), allowing the market penetration of these devices, it is necessary to reduce the costs of the components, in particular the cathode catalysts based on platinum. Another issue of these fuel cells is related to methanol crossover through the polymeric membrane, which creates a mixed potential at the cathode and decreases the overall efficiency. For this reason the development of methanol-tolerant cathode catalysts that are cheaper than Pt are of great importance in this field. In this chapter a short review analysis on Pt-free catalysts, mainly based on Pd and platinum group metal-free compounds with the general formula M–N–C (M being a transition metal such as Fe or Co) for the cathode, with good methanol-tolerance characteristics, has been carried out. Preparation procedures for the catalysts and physicochemical characteristics are reported and discussed in correlation with the DMFC performance., Introduction.-- Palladium as oxygen reduction reaction catalyst in direct methanol fuel cells.-- Non platinum-group-metal electrocatalysts based on M–N–C.-- Conclusion

The membrane-electrodes assembly (MEA) is the core of the Polymer Electrolyte Fuel Cell (PEFC). It consists of a membrane, catalytic (CL) and gas diffusion layers (GDL). In order to manufacture MEAs with suitable performance, a hot-pressing procedure is generally used. The relevant parameters are the temperature, pressure and time of hot-pressing. Such variables need to be adjusted as a function of the type of ionomer used in the catalytic layer and membrane. In this study, an evaluation of the temperature of hot-pressing was carried out and its influence on MEA electrochemical performance was assessed. In particular, preparation trials of MEAs were carried out with reinforced experimental membranes based on Aquivion® short-side-chain PFSA (by Solvay Specialty Polymers). The membranes were coupled to gas diffusion electrodes, and MEAs were manufactured using different temperatures for the hot-pressing procedure in order to evaluate their influence on the electrochemical performance of PEFCs, in the temperature range of 80–95 °C, with low relative humidity of the reactant gases. The electrochemical performance of the prepared MEAs was tested in a H2/Air 25 cm2 single cell in terms of polarization curves and accelerated stress test (AST).

This paper reports on the most recent achievements obtained at CNR-ITAE on the co-electrolysis of H2O and CO2 with solid oxide electrolysers. The experiments carried out are addressed to the use of a coating layer on the cathode and to find proper operating conditions in order to affect positively the outlet gas value and the yield of methane. Therefore, in this manuscript are reported experimental results concerning the development of materials, electrochemical characterization of cells and analysis of effluent gas.

The controlled dispersion of polymeric sulfonic acids on suitable heterogeneous supports paves the way to a new catalytic method for the oxidation of a variety of benzylic methylenes to the corresponding carbonyls by using hydrogen peroxide; narrowly dispersed silica nanoparticles covered by fluorinated sulfonic acids ionomers allow selective oxidation of toluene to benzaldehyde, minimizing undesired side reactions and formation of wastes.

Social isolation is a powerful stressor capable of affecting brain plasticity and function. In the case of breast cancer, previous data indicate that stressful experiences may contribute to a worse prognosis, activating neuroendocrine and metabolism pathways, although the mechanisms underlying these effects are still poorly understood. In this study, we tested the hypothesis that chronic isolation stress (IS) may boost hypothalamic–pituitary–adrenal (HPA) axis activity, leading to changes in the hypothalamic expression of genes modulating both mood and metabolism in an animal model of breast cancer. This centrally activated signaling cascade would, in turn, affect the mammary gland microenvironment specifically targeting fat metabolism, leading to accelerated tumor onset. MMTVNeuTg female mice (a model of breast cancer developing mammary hyperplasia at 5 months of age) were either group-housed (GH) or subjected to IS from weaning until 5 months of age. At this time, half of these subjects underwent acute restraint stress to assess corticosterone (CORT) levels, while the remaining subjects were characterized for their emotional profile in the forced swimming and saccharin preference tests. At the end of the procedures, all the mice were sacrificed to assess hypothalamic expression levels of Brain-derived neurotrophic factor (Bdnf), Neuropeptide Y (NpY), Agouti-Related Peptide (AgRP), and Serum/Glucocorticoid-Regulated Protein Kinase 1 (SgK1). Leptin and adiponectin expression levels, as well as the presence of brown adipose tissue (BAT), were assessed in mammary fat pads. The IS mice showed higher CORT levels following acute stress and decreased expression of NpY, AgRP, and SgK1, associated with greater behavioral despair in the forced swimming test. Furthermore, they were characterized by increased consumption of saccharin in a preference test, suggesting an enhanced hedonic profile. The IS mice also showed an earlier onset of breast lumps (assessed by palpation) accompanied by elevated levels of adipokines (leptin and adiponectin) and BAT in the mammary fat pads. Overall, these data point to IS as a pervasive stressor that is able to specifically target neuronal circuits, mastered by the hypothalamus, modulating mood, stress reactivity and energy homeostasis. The activation of such IS-driven machinery may hold main implications for the onset and maintenance of pro-tumorigenic environments.

6 Figuras, 4 Tablas, The large-scale application of polymer electrolyte membrane fuel cells (PEMFCs) requires a reduction of the costs and an improvement in performance and stability. Particularly, the automotive market needs the PEMFC works under harsh conditions (high temperature, low relative humidity, etc.), maintaining a good performance level and low degradation. These operating conditions permit to mitigate the constraints concerning the thermal and water management allowing both a simplification and a volume reduction of the system inside the car with a strong impact on costs and reliability. However, PEMFCs require the development of the components such as catalysts, ionomers and membranes with a proper stability. In this work, PtCo/KB and Pt/KB electrocatalysts were investigated with the aim of verifying the performance and stability, coupling them with an innovative reinforced Aquivion® membrane. An optimization of the catalytic ink composition was carried out, according to the different ionomers characteristics to be used in the catalytic layer in order to reduce the degradation level. The stability is assessed by considering the variations of the performance and electrochemical parameters, such as electrochemical surface area (ECSA) and mass activity (jm), at the beginning and end of accelerated stress test procedures., The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) for Fuel Cell and Hydrogen Joint Technology Initiative under Grant no 303452 (IMPACT).

14 Figuras., Various Pt-based materials (unsupported Pt, PtRu, PtCo) were investigated as catalysts for recombining hydrogen and oxygen back into water. The recombination performance correlated well with the surface Pt metallic state. Alloying cobalt to platinum was observed to produce an electron transfer favouring the occurrence of a large fraction of the Pt metallic state on the catalyst surface. Unsupported PtCo showed both excellent recombination performance and dynamic behaviour. In a packed bed catalytic reactor, when hydrogen was fed at 4% vol. in the oxygen stream (flammability limit), 99.5% of the total H2 content was immediately converted to water in the presence of PtCo thus avoiding safety issues. The PtCo catalyst was thus integrated in the anode of the membrane-electrode assembly of a polymer electrolyte membrane electrolysis cell. This catalyst showed good capability to reduce the concentration of hydrogen in the oxygen stream under differential pressure operation (1–20 bar), in the presence of a thin (90 μm) Aquivion® membrane. The modified system showed lower hydrogen concentration in the oxygen flow than electrolysis cells based on state-of-the-art thick polymer electrolyte membranes and allowed to expand the minimum current density load down to 0.15 A cm−2. This was mainly due to the electrochemical oxidation of permeated H2 to protons that were transported back to the cathode. The electrolysis cell equipped with a dual layer PtCo/IrRuOx oxidation catalyst achieved a high operating current density (3 A cm−2) as requested to decrease the system capital costs, under high efficiency conditions (about 77% efficiency at 55 °C and 20 bar). Moreover, the electrolysis system showed reduced probability to reach the flammability limit under both high differential pressure (20 bar) and partial load operation (5%), as needed to properly address grid-balancing service., CNR-ITAE authors acknowledge the financial support from the NEPTUNE project. This project has received funding from Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 779540. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme and Hydrogen Europe and Hydrogen Europe Research. The authors also thank Solvay Specialty Polymers for supplying the membrane and the ionomer, ITM Power (UK) for supplying the high-pressure single cell test fixture and Mr. Giuseppe Monforte for the XPS analysis.

1 figure.-- Abstract of the poster presented at the VII International Symposium SRUK/CERU (2019), organized by the Society of Spanish Researchers in the United Kingdom. 28th-30th June 2019, Liverpool (United Kingdom)., Graphene oxide nanomaterials, specifically reduced few-layer graphene oxide (rFLGO) sheets and reduced graphene oxide quantum dots (rGOQD), were explored as active and cost-effective counter electrodes for dye-sensitized solar cells (DSSCs). The synthesis strategy adopted in this work for these materials is based on an economic and easily scalable route of exfoliation of multi-wall carbon nanotubes (Top-Down approach). This allows the easy tailoring of rFLGO/rGOQD size and oxidation degree for their use as bulk material in counter electrodes, having a significant influence on the photovoltaic performance and stability. Despite the slower kinetics of carbon for the reduction of triiodide compared to platinum, they are characterized by low cost and promising stability. The electrochemical performance of DSSC assembled with either rFLGO or rGOQD at the counter electrode is correlated to their most important physico-chemical features. The domain size of graphene sheets had an important effect on the performance at the counter electrode, with quantum dots performing 13% higher efficiency than rFLGO, correlated with a higher density of active sites. Both graphene nanostructures exhibited a better stability behavior upon electrochemical cycling and seasoning of the cells as compared to Pt counter electrode., ICB-CSIC authors acknowledge the Raw Materials Network of Infrastructure ITO substitution in opto-electronic devices (European Union), and the funding of the FEDER and the Spanish Economy and Competitiveness Ministry (MINECO) (ENE2011-28318-C03-01 and ENE2014-52189-C02-01-R). JLP and DS thank MINECO for their Ramon y Cajal research contracts (RyC-2013-12494 and RyC-2016-20944). CNR-ITAE authors acknowledge the financial support from the FotoH2 project. This project has received funding from the European Union s Horizon 2020 research and innovation programme under Grant Agreement n° 760930.

Methanol crossover through a polymer electrolyte membrane has numerous negative effects on direct methanol fuel cells (DMFCs) because it decreases the cell voltage due to a mixed potential (occurrence of both oxygen reduction and methanol oxidation reactions) at the cathode, lowers the overall fuel utilization and contributes to long-term membrane degradation. In this work, an investigation of methanol transport properties of composite membranes based on sulfonated polysulfone (sPSf) and modified silica filler is carried out using the PFG-NMR technique, mainly focusing on high methanol concentration (i.e., 5 M). The influence of methanol crossover on the performance of DMFCs equipped with low-cost sPSf-based membranes operating with 5 M methanol solution at the anode is studied, with particular emphasis on the composite membrane approach. Using a surface-modified-silica filler into composite membranes based on sPSf allows reducing methanol cross-over of 50% compared with the pristine membrane, making it a good candidate to be used as polymer electrolyte for high energy DMFCs.

Plasma IL-17A detection in Langerhans Cell Histiocytosis (LCH) is currently a source of debate. Indeed, 500-P07G (PeproTech) and 41802 (R&D Systems) anti-IL-17A antibodies have been suspected to recognize nonspecific proteins. To resolve this discrepancy, we set up two new ELISAs by using 41802 or neutralizing eBio64CAP17 (eBioscience) capture monoclonal antibodies that we compared to the commercial PeproTech ELISA kit. The three ELISAs, called E_500-P07G, E_41802 and E_eBio64CAP17, differ in their anti-IL-17A capture antibodies: either polyclonal, monoclonal or neutralizing monoclonal antibodies, respectively. Here, we show that these ELISAs had a similar capacity to specifically detect recombinant or native human IL-17A. However, a significantly lower plasma IL-17A detection was obtained with E_41802 compared to the two other ELISAs. Both E_500-P07G and E_eBio64CAP17 showed similar results. Consequently, we propose that the use of E_500-P07G and E_eBio64CAP17 may ensure more accurate and reliable results in the context of LCH studies. The highest plasma IL-17A levels in LCH patients compared to controls detected by both E_500-P07G and E_eBio64CAP17 ELISAs led us to propose these latter as reference techniques to investigate IL-17A as a potential new biomarker in LCH.•The customization of a new E_eBio64CAP17 ELISA is suitable to detect human IL-17A.•E_eBio64CAP17 ELISA protocol differs only in the anti-IL-17A capture antibody compared to the commercial E_500-P07G PeproTech kit.•Data generated using the E_eBio64CAP17 ELISA are consistent with the PeproTech kit., Graphical abstract Image, graphical abstract

The co-electrolysis of CO2 and H2O at intermediate temperature is a viable approach for the power-to-gas conversion that deserves for further investigation, considering the need for green energy storage. The commercial solid oxide electrolyser is a promising device, but it is still facing to solve issues concerning the high operating temperatures and the improvement of gas value. In this paper we reported the recent findings of a simple approach that we have amply suggested for solid oxide cells consisting in the addition of a functional layer coated to the fuel electrode of commercial electrochemical cells. This approach simplifies the transition to the next generation of cells manufactured with the most promising materials currently developed and improves the gas value in the outlet stream of cell. Here, the material in use as a coating layer consisted of a Ni-modified La0.6Sr0.4Fe0.8Co0.2O3 which was developed and demonstrated as promising fuel electrode for solid oxide fuel cells. The results discussed in this paper proved the positive role of Ni-modified perovskite as a coating layer for the cathode, since an improvement of about twice was obtained about the quality of gas produced.

The co-electrolysis of CO2 and H2O at an intermediate temperature is a viable approach for the power-to-gas conversion that deserves further investigation, considering the need for green energy storage. The commercial solid oxide electrolyser is a promising device, but it is still facing issues concerning the high operating temperatures and the improvement of gas value. In this paper we reported the recent findings of a simple approach that we have suggested for solid oxide cells, consisting of the addition of a functional layer coated to the fuel electrode of commercial electrochemical cells. This approach simplifies the transition to the next generation of cells manufactured with the most promising materials currently developed, and improves the gas value in the outlet stream of the cell. Here, the material in use as a coating layer consists of a Ni-modified La0.6Sr0.4Fe0.8Co0.2O3, which was developed and demonstrated as a promising fuel electrode for solid oxide fuel cells. The results discussed in this paper prove the positive role of Ni-modified perovskite as a coating layer for the cathode, since an improvement of about twofold was obtained as regards the quality of gas produced.

Tandem photo-electro-chemical cells composed of an assembly of a solid electrolyte membrane and two low-cost photoelectrodes have been developed to generate green solar fuel from water-splitting. In this regard, an anion-exchange polymer&ndash, electrolyte membrane, able to separate H2 evolved at the photocathode from O2 at the photoanode, was investigated in terms of ionic conductivity, corrosion mitigation, and light transmission for a tandem photo-electro-chemical configuration. The designed anionic membranes, based on polysulfone polymer, contained positive fixed functionalities on the side chains of the polymeric network, particularly quaternary ammonium species counterbalanced by hydroxide anions. The membrane was first investigated in alkaline solution, KOH or NaOH at different concentrations, to optimize the ion-exchange process. Exchange in 1M KOH solution provided high conversion of the groups, a high ion-exchange capacity (IEC) value of 1.59 meq/g and a hydroxide conductivity of 25 mS/cm at 60 &deg, C for anionic membrane. Another important characteristic, verified for hydroxide membrane, was its transparency above 600 nm, thus making it a good candidate for tandem cell applications in which the illuminated photoanode absorbs the highest-energy photons (&lt, 600 nm), and photocathode absorbs the lowest-energy photons. Furthermore, hydrogen crossover tests showed a permeation of H2 through the membrane of less than 0.1%. Finally, low-cost tandem photo-electro-chemical cells, formed by titanium-doped hematite and ionomer at the photoanode and cupric oxide and ionomer at the photocathode, separated by a solid membrane in OH form, were assembled to optimize the influence of ionomer-loading dispersion. Maximum enthalpy (1.7%), throughput (2.9%), and Gibbs energy efficiencies (1.3%) were reached by using n-propanol/ethanol (1:1 wt.) as solvent for ionomer dispersion and with a 25 &micro, L cm&minus, 2 ionomer loading for both the photoanode and the photocathode.

Exsolved perovskites can be obtained from lanthanum ferrites, such as La0.6Sr0.4Fe0.8Co0.2O3, as result of Ni doping and thermal treatments. Ni can be simply added to the perovskite by an incipient wetness method. Thermal treatments that favor the exsolution process include calcination in air (e.g., 500 °C) and subsequent reduction in diluted H2 at 800 °C. These processes allow producing a two-phase material consisting of a Ruddlesden–Popper-type structure and a solid oxide solution e.g., α-Fe100-y-zCoyNizOx oxide. The formed electrocatalyst shows sufficient electronic conductivity under reducing environment at the Solid Oxide Fuel Cell (SOFC) anode. Outstanding catalytic properties are observed for the direct oxidation of dry fuels in SOFCs, including H2, methane, syngas, methanol, glycerol, and propane. This anode electrocatalyst can be combined with a full density electrolyte based on Gadolinia-doped ceria or with La0.8Sr0.2Ga0.8Mg0.2O3 (LSGM) or BaCe0.9Y0.1O3-δ (BYCO) to form a complete perovskite structure-based cell. Moreover, the exsolved perovskite can be used as a coating layer or catalytic pre-layer of a conventional Ni-YSZ anode. Beside the excellent catalytic activity, this material also shows proper durability and tolerance to sulfur poisoning. Research challenges and future directions are discussed. A new approach combining an exsolved perovskite and an NiCu alloy to further enhance the fuel flexibility of the composite catalyst is also considered. In this review, the preparation methods, physicochemical characteristics, and surface properties of exsoluted fine nanoparticles encapsulated on the metal-depleted perovskite, electrochemical properties for the direct oxidation of dry fuels, and related electrooxidation mechanisms are examined and discussed.

Exsolved perovskites can be obtained from lanthanum ferrites, such as La0.6Sr0.4Fe0.8Co0.2O3, as result of Ni doping and thermal treatments. Ni can be simply added to the perovskite by an incipient wetness method. Thermal treatments include calcination in air (e.g., 500 °C) and subsequent reduction in diluted H2 at 800 °C to favor the exsolution process. The chemistry of the nanoparticles exsoluted on the substrate surface can be further modulated by a post treatment in air. These processes allow to produce a two-phase material consisting of a Ruddlesden-Popper type structure and a solid oxide solution e.g. α-Fe100-y-zCoyNizOx oxide. The formed electro-catalyst shows sufficient electronic conductivity under reducing environment at the SOFC anode. Outstanding catalytic properties are observed for the direct oxidation of dry fuels in SOFCs, including H2, methane, syngas, methanol, glycerol and propane. This anode electrocatalyst can be combined with full density electrolyte based on Gadolinia-doped Ceria or with La0.8Sr0.2Ga0.8Mg0.2O3 (LSGM) or BaCe0.9Y0.1O3-δ (BYCO) to form a complete perovskite structure-based cell. Moreover, the exsolved perovskite can be used as a coating layer or catalytic pre-layer of a conventional Ni-YSZ anode. Beside the excellent catalytic activity, this material also shows proper durability and tolerance to sulphur poisoning. In this mini review, preparation methods, physico-chemical characteristics, surface properties of exsoluted and core-shell nanoparticles encapsulated on the metal-depleted perovskite substrate surface, electrochemical properties for the direct oxidation of dry fuels and related electrooxidation mechanisms are examined and discussed.

Here, in-house Co N C and Fe N C have been prepared by, first, chelating the metals (Co or Fe) with ethylene diamine tetra acetic acid, known as EDTA (nitrogen precursor). UV–Visible (UV–Vis) spectrometry has been used to ensure the chelated metal formation. In the next step, the chelated metals have been deposited on a high surface area oxidized carbon support to increase the electrical conductivity. The latter composite material has been thermally treated at 800 °C (CoNC8 and FeNC8) or 1000 °C (CoNC10 and FeNC10) in nitrogen atmosphere in order to create the catalytic sites that will be able to perform the oxygen reduction reaction (ORR) in the acid medium. Electrochemical tests have been carried out to investigate the activity and durability of the electro-catalysts for the ORR. Methanol tolerance properties have been also evaluated for a possible application in direct methanol fuel cells. It appears that FeNC8 is the most active electrocatalyst in the presence of methanol in the base electrolyte, thus showing promising characteristics for direct methanol fuel cells. Instead, stability tests of these metal nitrogen catalysts indicate the best resistance to corrosion for the catalysts treated at 1000 °C.

We report a facile synthetic method for the preparation of titanium–tantalum oxide by means of a modified Adam’s method. This new method allowed obtaining Ti0.8Ta0.2O2 with a high surface area (234 m2 g−1), to be used as catalyst support for Pd nanoparticles. Cyclic voltammetry and linear sweep voltammetry measurements confirm the noticeable oxygen reduction reaction (ORR) activities of the Pd/Ti0.8Ta0.2O2 electrocatalyst in alkaline electrolytes, along with a high-selectivity towards a 4e− pathway. The good ORR performance for the Pd/Ti0.8Ta0.2O2 could arise from both the strong metal-support interaction and the contribution of the Ti0.8Ta0.2O2 in facilitating the ORR process, acting as co-catalyst. However, the stability of this catalyst seems insufficient for practical applications.

Oxygen reduction and evolution reactions occur on the same electrode in metal-air batteries and in unitized reversible fuel cells. Bifunctional oxygen electrodes should be able to perform both reactions with good chemical stability over a wide range of potentials. Perovskites are recognized for their good activity towards the oxygen evolution reaction. In this work, a La 0.6 Sr 0.4 Fe 0.8 Co 0.2 O 3 perovskite (LSFCO) is proposed and investigated for operation as both oxygen reduction and evolution catalyst in an aqueous alkaline solution. In order to improve the conductivity of the electrode, LSFCO is mixed with a high surface area conductive carbon black. The so-obtained catalyst is investigated in a half-cell by using a three-electrode configuration, in a KOH solution at ambient temperature, and compared to a Pd/C catalyst. Thinking of a possible use in a rechargeable metal-air battery operating in aqueous media (such as Fe-air, Zn-air, etc.), LSFCO has been subjected to charge-discharge cycles at high current density. Results have proved that although LSFCO is less active than Pd/C for the oxygen reduction reaction, it is significantly more active for the oxygen evolution reaction. Besides, the LSFCO-based catalyst shows enhanced stability when subjected to charge-discharge cycles. The low cost of the perovskite and a good compromise between activity and stability, makes it a promising catalyst for electrochemical devices requiring bifunctionality.

Carbon-supported 30% Pd-based catalysts such as Pd/C, Pd4Co1/C and Pd10Co1/C were prepared by the sulphite complex route and physico-chemically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). The electrochemical investigation was carried out in half cell and direct methanol fuel cell (DMFC) to evaluate the performance, the tolerance to permeated methanol and the durability of the Pd-based electrocatalysts. For comparison, a commercial 30% Pt/C catalyst was also electrochemically investigated. The advantage of using a high methanol concentration in DMFCs is related to a high energy density. Unfortunately, methanol crossover causes a mixed potential at Pt cathode catalysts reducing the overall cell efficiency, which is exacerbated with high methanol concentration (10 M) at the anode side. Pd and Pd-Co alloys based electrocatalysts exhibited high methanol tolerance properties, as evidenced in the half cell characterization, which led also to high performances in single cell configuration (DMFC). Thus, Pd-based electrodes represent a reliable way to minimize the cost in low temperature fuel cells, providing a higher performance than that of Pt-based electrodes at high methanol concentration. Moreover, the durability tests highlighted that including a small amount of cobalt in the crystalline structure of Pd resulted in better durability in terms of resistance to corrosion phenomena.

Solid oxide fuel cells (SOFCs) based on conventional nickel-yttria stabilised zirconia (Ni-YSZ) anodes can not be fed directly with organic fuels because of the associated formation of carbon deposits. This work explores a simple approach to solve such relevant limiting factor that affects the direct utilization of conventional dry hydrocarbons in SOFCs. The approach consists in depositing a composite multifunctional electrocatalyst layer on the SOFC anode to work as an internal integrated fuel processor. This study investigates the direct oxidation of dry ethanol in the modified SOFC and provides an evaluation of cell performance. A protective layer based on a composite made of Ni-modified perovskite and gadolinia-doped ceria is coated on a conventional SOFC anode based on Ni-YSZ. Besides the oxygen storage properties of ceria, the composite electrocatalyst is characterized by the presence of dispersed Ni-alloy @ FeOx core-shell nanoparticles in the outer layers and surface basicity properties. Efficient dehydrogenation of ethanol, carbon deposition-free cracking reactions and internal reforming assisted by a H-2/H2O "shuttle mechanism" appear as the key steps involved in the direct oxidation of the organic fuel at the modified SOFC anode. The best performance achieved for the dry ethanol-fed SOFC is about 0.65 W cm(-2) at 0.6V and 800 degrees C. No carbon deposition is observed both on the Ni-YSZ supporting layer and protective Ni-doped perovskite layer after a durability test of more than 100 h. (C) 2017 Elsevier B.V. All rights reserved.

For the first time a long-term (500 h) durability study in direct methanol fuel cells (DMFCs) is carried out on a Platinum Group Metal-free (PGM-free) cathodic electro-catalyst commercially available on market. The electro-catalyst is tested for 500 h at a fixed cell voltage (0.3 V), recording the polarization curves during the operation. A drastic decrease in performance is observed after the first 100 h (from 220 to 75 mA cm−2); afterwards, the decrease is flatter, passing from 75 to 25 mA cm−2 (at 500 h). The causes of this performance degradation are investigated by postmortem physicochemical analyzes, such as X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with X-ray energy dispersive analysis (EDX). Possible reasons of degradation are indicated to be PGM-free catalyst aggregation, carbon and nitrogen species decrease, Ruthenium dissolution and migration from the anode to the cathode, poisoning both membrane and cathode catalyst.

This work was focused on the synthesis of tantalum (Ta) modified TiO2 mixed oxides and their structural and surface properties characterization using XRD, XPS, BET and H-2-TPR techniques. Ta-modified TiO2 samples were synthesized using a sol-gel procedure and evaluated for potential application as electrocatalysts support. The tantalum (Ta) modified TiO2 mixed oxides showed a unimodal nanoporous structure with pore sizes ranging from 3 nm to 5 nm. Concomitant with their higher surface area and pore volume, the mixed oxides were nanocrystalline and significantly smaller than Ti and Ta single oxides prepared by the same method (7-8 nm). A dominant anatase phase was detected by XRD at low calcination temperature, while the crystallographic structure becomes ruffle when the sample was treated at 850 degrees C. By incorporating Ta into TiO2, the lattice parameters were changed, the reducibility of mixed oxides was increased and the surface oxygen deficiency was significantly enhanced as well. The present study clearly established that the structural (crystal phase, crystal size, nanoporosity, pore size) and surface properties (reducibility, oxygen deficiency, acidity, oxidation activity) of the Ta-modified TiO2 mixed oxides can be tailored by modifying the sol-gel procedure and the thermal treatment. A palladium catalyst supported on this oxide (30% Pd/TaTiOx) was prepared by the sulphite complex route. The catalyst was ex-situ characterized by physico-chemical analysis and investigated for the ORR to evaluate its activity, stability and durability. The Pd/TaTiO. catalyst, compared with catalysts from literature, showed a very promising stability, figuring good perspectives for application in fuel cells and/or electrolyzers. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

The design of a bifunctional air electrode able to carry out both the oxygen reduction and evolution reactions in an alkaline environment is essential for the progress of new-generation energy conversion and storage devices. Alkaline systems allow the use of non-noble metals, which favors a considerable reduction of the system cost. In this work, a cost-effective perovskite, La 0.6 Sr 0.4 Fe 0.8 Co 0.2 O 3 , has been investigated as bifunctional catalyst in a 6 M KOH alkaline solution. The perovskite was mixed with an experimental carbon black, characterized by a graphitic structure and a specific surface area of 220 m 2 g −1 . The perovskite-carbon composite was compared to a Pd/C catalyst (employing the same carbon black as support). Generally, bifunctional catalysts are subjected to high electrochemical potentials, particularly during the oxygen evolution. In order to assess the stability of the bifunctional catalyst, several accelerated degradation tests were performed. Results proved that the perovskite-carbon composite showed good performance for both reactions, in particular for the oxygen evolution. Furthermore, it also presented enhanced stability vs. Pd/C when subjected to degradation tests, maintaining a constant potential over time, even working at high current densities (80 and 125 mA cm −2 ). This material is envisaged as a very promising bifunctional catalyst, in particular in terms of durability.

Bifunctional materials able to catalyze both the oxygen reduction (ORR) and the oxygen evolution (OER) reactions in alkaline media are still a challenge for the progress of energy conversion and storage devices such as metal-air batteries or unitized regenerative fuel cells. In this work, carbon nanofibers synthesized by electrospinning are modified with a combination of cobalt oxide and metallic cobalt (CoO-Co/CNF) and studied as a bifunctional air electrode for metal-air batteries. The performance of CoO-Co/CNF for both reactions is compared with state-of-the-art catalysts such as Pt/C and IrO 2 . The combination of cobalt oxide and metallic cobalt, finely distributed on the surface of graphitic carbon nanofibers, leads to a bifunctional catalyst with a half-wave potential for the ORR slightly better than Pt/C and a reversibility (ΔE OER-ORR ) of 809 mV. The stability of CoO-Co/CNF is assessed by means of different stress tests: polarizations at high electrochemical potentials (2 V vs. RHE), rapid charge-discharge cycles at ±80 mA cm −2 and long durability tests by charging for 12 h at 60 mA cm −2 and discharging for 8 h at −80 mA cm −2 . CoO-Co/CNF shows a remarkable stability, maintaining, at least, an 82% of its performance for the ORR after the stress tests, even when cycled for more than 100 h.

Pain relief achieved by co-administration of drugs acting at different targets is more effective than that obtained with conventional MOR selective agonists usually associated to relevant side effects. It has been demonstrated that simultaneously targeting different opioid receptors is a more effective therapeutic strategy. Giving the promising role for DOR in pain management, novel LP1-based analogues with different N -substituents were designed and synthesized with the aim to improve DOR profile. For this purpose, we maintained the phenyl ring in the N -substituent of 6,7-benzomorphan scaffold linked to an ethyl spacer bearing a hydroxyl/methyl or methoxyl group at carbon 2 or including it in a 1,4-benzodioxane ring. LP1 analogues were tested by competition binding assays. Compounds 6 (K i MOR = 2.47 nM, K i DOR = 9.6 nM), 7 (K i MOR = 0.5 nM and K i DOR = 0.8 nM) and 9 (K i MOR = 1.08 nM, K i DOR = 6.6 nM) retained MOR affinity but displayed an improved DOR binding capacity as compared to LP1 (K i MOR = 0.83 nM, K i DOR = 29.1 nM). Moreover, GPI and MVD functional assays indicated that compounds 6 (IC 50 = 49.2 and IC 50 = 10.8 nM), 7 (IC 50 = 9.9 and IC 50 = 11.8 nM) and 9 (IC 50 = 21.5 and IC 50 = 4.4 nM) showed a MOR/DOR agonist profile, unlike LP1 that was a MOR agonist/DOR antagonist (IC 50 = 1.9 and IC 50 = 1240 nM). Measurements of their antinociceptive effect was evaluated by mice radiant tail flick test displaying for compounds 6 , 7 and 9 ED 50 values of 1.3, 1.0 and 0.9 mg/kg, i.p., respectively. Moreover, the antinociceptive effect of compound 9 was longer lasting with respect to LP1. In conclusion the N -substituent nature of compounds 6 , 7 and 9 shifts the DOR profile of LP1 from antagonism to agonism.

The electrocatalytic reduction of CO2 to alcohols was investigated in a co-electrolysis cell based on a solid polymer electrolyte. PtRu/C and Ru/C catalysts were used in gas diffusion cathodes for the reduction of humidified CO2. An IrRuOx catalyst was used for the oxygen evolution from liquid water at the anode. This electrochemical reactor employed a perfluorosulfonic acid membrane electrolyte separator (Nafion®) and it was operated in a temperature range from 30 °C to 95 °C. The cathode catalysts were characterized by well-dispersed metal nanoparticles (2 nm mean particle size) on a carbon black support. Electrochemical polarization tests were carried out in the presence of CO2 or with humidified inert gas for comparison. The results evidenced that direct CO2 reaction on the catalysts surface was essentially occurring at low cell voltages (

High performing and cost effective nanocomposite membranes for DMFC application are synthesized by incorporating hygroscopic layered double hydroxides (LDH) particles into sulfonated polysulfone (sPSU). A significant improvement in the dimensional stability as well as in the water and methanol molecular dynamics of the sPSU_LDH composite membrane is observed in comparison with both pristine sPSU and Nafion 212. The strong electrostatic interaction occurring between positively charged LDH platelets and negatively charged polymer chains of sPSU alters the microstructure of the ionic domains, allowing an effective reduction of the methanol permeability whilst improving the proton conductivity. The methanol crossover measurements confirmed that sPSU_LDH membranes are able to withstand high methanol concentration without significant aftermath on the chemical stability of the electrolyte. The features enable the single DMFC assembled with the sPSU_LDH nanocomposite to achieve the remarkable power density of 150 mW cm−2 at 80 °C in 5 M methanol solution.

A new generation of high performing polymer electrolyte membranes with ultralow platinum group metal loading (in total 0.44 mgPGM cm− 2) has been developed and characterized. High performance was achieved for MEAs based on the short-side chain Aquivion membrane (E98-09S), stabilized Solvay ionomer (D98-06ASX), and optimized catalysts developed by CNR-ITAE (cathode 40% Pt on C and anode: Ir0.7Ru0.3OX). The high performance was verified on several scales ranging from small single cells (3–8 cm2) at CNR-ITAE and IRD to short three-cell stacks at ITM, the latter MEAs having an active area of 130 cm2. A 4000-h single cell steady-state test at 3 A cm− 2 shows that the degradation rate of the ultralow PGM MEAs is 8 μV/h. Minimal reversible degradation was recorded at 80°C although this is pronounced at low temperature (55°C). Current and thermal cycling proved to have limited impact on degradation.

A novel cermet based on CuSn-CGO is synthesized and used as a coating layer in the cathode of a conventional Solid Oxide Electrolyser for the co-electrolysis of H2O and CO2. Electrochemical experiments are carried out in the temperature range 525-600 degrees C by feeding reagents with a stoichiometry of 2:1 with respect to the operating current density (i.e. 150 mA cm(-2)). Outlet gas is analysed under OCV and operating conditions. The results are discussed in comparison with the theoretical values achievable under equilibrium. A stable electrochemical behaviour is observed in the studied temperature range. Although the performance of cell is affected by activation constraints in the temperature range 525-550 degrees C, minimal differences are observed with regard to the reduction kinetics of H2O and CO2. The analytical treatment of gas analysis data reveals that the coated layer promotes an increase of methane produced through the simultaneous reduction of H2O and CO2.

High electrochemical efficiency at elevated current densities and low H2 concentration in O2 can be achieved in PEM electrolysis using thin membrane and integrated recombination catalyst. An enhanced PtCo alloy recombination catalyst was synthesized and used at the anode of a membrane-electrode assembly (MEA). This allowed reducing the H2 concentration in the oxygen stream during electrolysis operation with a thin 50 μm perfluorosulfonic acid (PFSA) Aquivion® membrane. Both dual-layer and composite anode configurations (PtCo/IrRuOx) were investigated. The electrochemical performance of the MEAs containing the recombination catalyst was better than a bare MEA while producing a decrease of the H2 content at the anode. This allowed extending the partial load operation down to 5% at 55 °C under a differential pressure of 20 bar. The effects of the cathodic pressure and cell temperature (including evaluation of intermediate temperature operation at 140 °C) on both electrochemical performance and H2 concentration in the anode stream were investigated. An excellent performance of 4 A cm−2 at 1.75 V, at 140 °C, 20 bar cathode pressure, 5.5 bar anode pressure, with 0.6 mg cm−2 overall precious metal catalysts content was recorded. At 140 °C, the MEA also showed a moderate H2 concentration in O2 of about 2.3%, almost constant through most of the current density range.

The methodologies and experimental conditions used for the synthesis of cathode materials for electrochemical devices strongly influence their electrocatalytic performance. In particular, solution combustion synthesis is a convenient and versatile methodology allowing a fine-tuning of the properties of the material. In this work, we used for the first time a sucrose assisted-solution combustion synthesis for the preparation of Cerium and Cobalt-doped SrFeO3&ndash, &delta, electrocatalysts and we investigated the effect of polyethylene glycol (PEG) addition as a secondary fuel on their structural, microstructural, redox and electrochemical properties. The perovskite-type powders were characterized by X-ray diffraction coupled with Rietveld refinement, scanning, and high-resolution transmission electron microscopies, thermogravimetric analysis, nitrogen adsorption measurements, and temperature-programmed reduction. Electrical conductivity and overpotential measurements were performed after the deposition of the powders onto a Gd-doped ceria electrolyte pellet. Stable high-valence B-site cations were detected in the powders prepared from sucrose-PEG fuel mixtures, although a substantial improvement of the conductivity and a decrease of the overpotential values were obtained only with high molecular weight PEG. The superior electrochemical performance obtained using PEG with high molecular weight has been ascribed to a faster interaction of the powder with the oxygen gas phase favored by the nanometer-sized crystalline domains.

The electrocatalysis of oxygen in alkaline media is a challenging issue, influencing the performance of many electrochemical devices: fuel cells, unitized regenerative fuel cells, electrolyzers and metal-air batteries. This new manuscript proposes the synthesis of graphitic carbon nanofibers obtained by electrospinning with a cobalt-based spinel oxide, Co3O4/CNF. By means of a simple, reproducible and scalable method, a bifunctional catalyst with a promising performance is obtained, being able of carrying out the electrocatalysis of oxygen (oxidation of water, evolution and reduction of oxygen) in a basic solution. The combination of the active species on cobalt oxide (Co2+, Co3+ and Co-Nx), along with active species in the carbon nanofiber (graphitic and pyridinic N), gives rise to a catalyst with a remarkable reversibility (difference between E10 mA/cm2 (evolution) and Ehalf-wave-potential (reduction)): ΔE =795 mV), a low over-potential for the evolution of oxygen (η =416 mV) and 919 mV of oxygen reduction onset potential, very similar to that of a benchmark catalyst, Pt/C., Funding for this work was obtained from the “Accordo di Programma CNR-MiSE, Gruppo tematico Sistema Elettrico Nazionale – Progetto: Sistemi elettrochimici per l’accumulo di energia”.

Iron phthalocyanine (FePc) was used as iron/nitrogen/carbon source and templated with an ordered mesoporous silica (SBA-15), followed by heat treatment and leaching of SiO2 with hydrofluoric acid (sacrificial method). The Fe–N–C catalyst was tested for the oxygen reduction reaction using a rotating disk electrode (three electrode configuration) in the presence of methanol at different concentrations. Furthermore, the catalyst was investigated in a single cell configuration of a direct methanol fuel cell (DMFC) under different methanol concentrations and temperatures. The optimal operating condition was found to be 1 M at 110 °C, reaching 11.2 mW cm−2 using a commercial Pt-Ru black at the anode and the Fe–N–C at the cathode side. Interestingly, the cathodic catalyst was not dramatically affected by the presence of crossovered methanol, showing only a 12% drop in maximum power density with the highest methanol concentration of 10 M at the anode. A 3D multiphysics model was implemented to further explain the experimental DMFC performance data using a commercial platform (Comsol® Multiphysics v4.4a). The model agreed with the experimental data, showing a direct relationship between water saturation, and oxygen consumption, consequently oxygen starvation at the cathodic catalytic layer. The model considered two phases on the cathode side computed by extended Darcy law within the catalytic layer and the gas diffusion layer domains.

Bifunctional air electrodes catalysing both the oxygen reduction and oxygen evolution reactions are essential in electrochemical devices such as metal-air batteries and regenerative fuel cells. Unfortunately, highly positive electrochemical potentials take place at the positive electrode (air electrode) especially during the oxygen evolution reaction. This is a highly corrosive condition and, thus, more stable catalysts are required. In the present work, titanium suboxides (TinO2n−1) have been studied as palladium catalyst support for the air electrode of metal-air batteries. The performance of Pd/TinO2n−1 towards both the oxygen reduction and the oxygen evolution reactions in alkaline media was analysed. Besides, the stability of the catalysts was assessed by subjecting them to accelerated stress tests. These catalysts were compared to a Pd catalyst supported on a conventional carbon black (Vulcan). Pd/TinO2n−1 showed a suitable activity as bifunctional catalyst, comparable to Pd/Vulcan, particularly for the ORR. Besides, it showed a higher performance with time than the carbonaceous support-based catalyst when subjected to harsh electrochemical conditions (1.8 V vs. RHE for 8 h). This indicates a more suitable stability for application in metal-air batteries.