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Aiming at the energy efficient use and valorization of carbon dioxide in the framework of decarbonization studies and hydrogen research, a novel dielectric barrier discharge (DBD) reactor has been designed, constructed and developed. This test rig with water cooled electrodes is capable of a plasma power tunable in a wide range from 20W to 2 kW per unit. The reactor was designed to be ready for catalysts and membrane integration aiming at a broad range plasma conditions and processes, including low to moderate high pressures (0.05–2 bar). In this paper, preliminary studies on the highly endothermic dissociation of CO2, into O2 and CO, in a pure, inert, and noble gas mixture flow are presented. These initial experiments were performed in a geometry with a 3 mm plasma gap in a chamber volume of 40cm3, where the process pressure was varied from few 200 mbar to 1 bar, using pure CO2, and diluted in N2. Initial results confirmed the well-known trade-off between conversion rate (up to 60%) and energy efficiency (up to 35%) into the dissociation products, as measured downstream of the reactor system. Improving conversion rate, energy efficiency and the trade-off curve can be further accomplished by tuning the plasma operating parameters (e.g. the gas flow and system geometry). It was found that the combination of a high-power, water-cooled plasma reactor, together with electronic and waveform diagnostic, optical emission and mass spectroscopies provides a convenient experimental framework for studies on the chemical storage of fast electric power transients and surges. [ABSTRACT FROM AUTHOR]

Graphene-based derivatives with covalent functionalization and well-defined stoichiometry are highly desirable in viewof their application as functional surfaces. Here, we have evaluated by ab initio calculations the energy of formation and the phase diagram of hydroxylated graphane structures, i.e., fully functionalized graphene derivatives coordinated with -H and -OH groups. We compared these structures to different hydrogenated and non-hydrogenated graphene oxide derivatives, with high level of epoxide and hydroxyl groups functionalization. Based on our calculations, stable phases of hydroxylated graphane with lowand high contents of hydrogen are demonstrated for high oxygen and hydrogen partial pressure, respectively. Stable phases of graphene oxide with a mixed carbon hybridization are also found. Notably, the synthesis of hydroxylated graphane has been recently reported in the literature. [ABSTRACT FROM AUTHOR]

Summary: Nanostructured cobalt oxide anodes for alkaline membrane electrolysis cell (AME) were fabricated by electrophoretic deposition (EPD) method directly on AISI‐316 sintered metal fiber substrate, and the effect of different amounts of cobalt oxide was evaluated. The influence of the deposition condition on the microstructure and catalytic activity of the anodes was analyzed, showing different characteristics compared to the substrate steel structure. In particular, the catalytic activity for the oxygen evolution reaction (OER) in KOH 0.5 M solution showed an increase depending on the EPD conditions. The composite electrodes were also compared to other materials commonly applied in alkaline electrolysis in order to verify their effective electrocatalytic activity. In particular, the results were compared with electroplated platinum and cobalt with the aim of identifying the better synthesis technique. The results show that the EPD methodology can be adopted to provide an effective method for improving steel anodes of alkaline membrane electrolyzers. [ABSTRACT FROM AUTHOR]

Graphene‐based materials represent a useful tool for the realization of novel neural interfaces. Several studies have demonstrated the biocompatibility of graphene‐based supports, but the biological interactions between graphene and neurons still pose open questions. In this work, the influence of graphene films with different characteristics on the growth and maturation of primary cortical neurons is investigated. Graphene films are grown by chemical vapor deposition progressively lowering the temperature range from 1070 to 650 °C to change the lattice structure and corresponding electrical conductivity. Two graphene‐based films with different electrical properties are selected and used as substrate for growing primary cortical neurons: i) highly crystalline and conductive (grown at 1070 °C) and ii) highly disordered and 140‐times less conductive (grown at 790 °C). Electron and fluorescence microscopy imaging reveal an excellent neuronal viability and the development of a mature, structured, and excitable network onto both substrates, regardless of their microstructure and electrical conductivity. The results underline that high electrical conductivity by itself is not fundamental for graphene‐based neuronal interfaces, while other physico–chemical characteristics, including the atomic structure, should be also considered in the design of functional, bio‐friendly templates. This finding widens the spectrum of carbon‐based materials suitable for neuroscience applications. [ABSTRACT FROM AUTHOR]

A novel black organoammonium iodoplumbate semiconductor, namely phenyl viologen lead iodide C22H18N2(PbI3)2 (PhVPI), was successfully synthesized and characterized. This material showed physical and chemical properties suitable for photovoltaic applications. Indeed, low direct allowed band gap energy (Eg = 1.32 eV) and high thermal stability (up to at least 300 °C) compared to methylammonium lead iodide CH3NH3PbI3 (MAPI, Eg = 1.5 eV) render PhVPI potentially attractive for solar cell fabrication. The compound was extensively characterized by means of X-ray diffraction (performed on both powder and single crystals), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), UV-photoelectron spectroscopy (UPS), FT-IR spectroscopy, TG-DTA, and CHNS analysis. Reactivity towards water was monitored through X-ray powder diffraction carried out after prolonged immersion of the material in water at room temperature. Unlike its methyl ammonium counterpart, PhVPI proved to be unaffected by water exposure. The lack of reactivity towards water is to be attributed to the quaternary nature of the nitrogen atoms of the phenyl viologen units that prevents the formation of acid–base equilibria when in contact with water. On the other hand, PhVPI's thermal stability was evaluated by temperature-controlled powder XRD measurements following an hour-long isothermal treatment at 250 and 300 °C. In both cases no signs of decomposition could be detected. However, the compound melted incongruently at 332 °C producing, upon cooling, a mostly amorphous material. PhVPI was found to be slightly soluble in DMF (∼5 mM) and highly soluble in DMSO. Nevertheless, its solubility in DMF can be dramatically increased by adding an equimolar amount of DMSO. Therefore, phenyl viologen lead iodide can be amenable for the fabrication of solar devices by spin coating as actually done for MAPI-based cells. The crystal structure, determined by means of single crystal X-ray diffraction using synchrotron radiation, turned out to be triclinic and consequently differs from the prototypal perovskite structure. In fact, it comprises infinite double chains of corner-sharing PbI6 octahedra along the a-axis direction with phenyl viologen cations positioned between the columns. Finally, the present determination of PhVPI's electronic band structure achieved through UPS and UV-Vis DRS is instrumental in using the material for solar cells. [ABSTRACT FROM AUTHOR]