Synthesis and Characterization of Cobalt and Nitrogen Co Doped Peat Derived Carbon Catalysts for Oxygen Reduction in Acidic Media

In this study, several peat derived carbons PDC were synthesized using various carbonization protocols. It was found that depending on the carbonization method, carbons with very different surface morphologies, elemental compositions, porosities, and oxygen reduction reaction ORR activities were obtained. Five carbons were used as carbon supports to synthesize Co N PDC catalysts, and five different ORR catalysts were acquired. The surface analysis revealed that a higher nitrogen content, number of surface oxide defects, and higher specific surface area lead to higher ORR activity of the Co N PDC catalysts in acidic solution. The catalyst Co N C 2 ZnCl2 , which was synthesized from ZnCl2 activated and pyrolyzed peat, showed the highest ORR activity in both rotating disk electrode and polymer electrolyte membrane fuel cell tests. A maximum power density value of 210 mW cm2 has been obtained. The results of this study indicate that PDCs are promising candidates for the synthesis of active non platinum group metal type catalyst

A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam

We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very stable, compact and cost-effective X-ray FEL facility driven by a low-energy and ultra-low-emittance electron beam travelling through short-period undulators. It delivers stable hard X-ray FEL radiation at 1-Å wavelength with pulse energies of more than 500 μJ, pulse durations of ~30 fs (root mean square) and spectral bandwidth below the per-mil level. Using special configurations, we have produced pulses shorter than 1 fs and, in a different set-up, broadband radiation with an unprecedented bandwidth of ~2%. The extremely small emittance demonstrated at SwissFEL paves the way for even more compact and affordable hard X-ray FELs, potentially boosting the number of facilities worldwide and thereby expanding the population of the scientific community that has access to X-ray FEL radiation

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

Perforated microelectrode arrays implanted in the regenerating adult central nervous system

Adult mammalian optic nerve axons are able to regenerate, when provided with the permissive environment of an autologous peripheral nerve graft, which is usually the sciatic nerve. This study demonstrates the ability of adult rat optic nerve axons to regenerate through the preformed perforations of a polyimide electrode carrier implanted at the interface between the proximal stump of the cut optic nerve and the stump of the peripheral nerve piece used for grafting. Evidence that retinal ganglion cells regenerated their axons through the perforated electrode carrier was obtained by retrograde labeling with a fluorescent dye deposited into the sciatic nerve graft beyond the nerve-carrier-nerve junction. The number of regenerating cells could be enhanced by injecting neuroprotective drugs like aurintricarboxylic acid and cortisol intravitreally. A second line of evidence was obtained by immunohistochemical staining with antibodies to neurofilament. Third, electrical activity of the regenerating nerves was recorded after stimulating the retina with a flash of light. The results suggest that a regenerating central nerve tract may serve as an experimental model to implant artificial microdevices to monitor the physiological and topographical properties of neurites passing through the device or to stimulate them, thus interfering with their potential to grow. This study reports for the first time that the optic nerve has unique properties, which aids in the realization of these goals

Carbon for Energy Storage Derived from Granulated White Sugar by Hydrothermal Carbonization and Subsequent Zinc Chloride Activation

© The Author(s) 2017. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY). Various electrochemical methods have been applied to establish the electrochemical characteristics of the electrical double layer capacitor consisting of the activated carbon material based electrodes and 1 M triethylmethylammonium tetrafluoroborate solution in acetonitrile and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid as the electrolytes. Activated carbon material used for the preparation of electrodes has been synthesized from hydrochar prepared via hydrothermal carbonization process of granulated white sugar solution in H2O, followed by activation with ZnCl2with a mass ratio of 1:4 at the temperature 700°C. High porosity and Brunauer-Emmett-Teller specific surface area (SBET = 2100 m2g-1), micropore surface area (Smicro= 2080 m2g-1) and total pore volume (Vtot = 1.05 cm3g-1) have been achieved for the granulated white sugar derived carbon (GWS carbon) material. Wide region of ideal polarizability (ΔE ≤ 3.0 V), short characteristic relaxation time (0.5 s and 4.0 s), high specific series capacitance (125 F g-1and 140 F g-1) and high energy density (39 W h kg-1and 48 W h kg-1) have been calculated for the GWS carbon material in 1 M triethylmethylammonium tetrafluoroborate solution in acetonitrile and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid, respectively, demonstrating that these systems are very promising for energy storage devices

Modification of micro/mesoporous carbon synthesis method from well decomposed peat using ZnCl2 additional activation step

ZnCl2 activation method was used to synthesize micro- and mesoporous carbon material from Estonian well decomposed peat. The synthesized material with the ZnCl2 activation step has an SBET value of 1270 m2 g─1, compared to the SBET value of 270 m2 g─1 without the activation step. The material was tested as an electrode material in a supercapacitor cell with ionic liquid as an electrolyte. The cyclic voltammetry, impedance spectroscopy and constant current charge/discharge cycles data show that the material is useable for stationary electricity storage in local small-scale wind farms and local PV electricity generating fields. The constant power test data show that very high energy densities E = 50 Wh kg─1 at moderate power densities P = 10 kW kg─1 can be achieved

Balance of the interfacial interactions of 4,4′-bipyridine at Bi(111) surface

The data from impedance spectroscopy, electrochemical in situ scanning tunnelling microscopy (STM), surface-enhanced infrared adsorption spectroscopy (SEIRAS) and density functional theory (DFT) were measured, combined and analysed to describe the 4,4′-bipyridine (4,4′-BP) adsorption at Bi(111) single crystal electrode from weakly acidified 0.5 M and 0.05 M Na 2SO4 aqueous solutions (pH ≈ 5.5÷6.0). The influence of electrode potential (E) on the adsorption kinetics of 4,4′-bipyridine on Bi(111) has been demonstrated. The capacitance pits in the differential capacitance versus E curve have been observed. The in situ STM data reveal two molecular patterns at different concentration of the supporting electrolyte. The stable adsorbate adlayer detectable by using the infrared spectroscopy method has been observed within E from -0.75 to -0.5 V (vs. Ag|AgCl sat. KCl). The results of DFT calculations and SEIRAS data have been used to establish the various possible orientations of the 4,4′-BP molecules at Bi(111) surface. The DFT investigation has been focused on the factors governing the self-assembly of 4,4′-BP, such as the intermolecular van der Walls attractions and interplay between the surface and the nanostructure lattices, both essential for the interfacial self-assembly