Iron-Air Rechargeable Battery

Embodiments include an iron-air rechargeable battery having a composite electrode including an iron electrode and a hydrogen electrode integrated therewith. An air electrode is spaced from the iron electrode and an electrolyte is provided in contact with the air electrode and the iron electrodes. Various additives and catalysts are disclosed with respect to the iron electrode, air electrode, and electrolyte for increasing battery efficiency and cycle life

Protonation and ring closure of stereoisomeric alpha-substituted cinnamic acids in superacidic media studied by 13C NMR spectroscopy and computations

Five alpha-substituted cinnamic acids [(E)- and (Z)-2,3-diphenyl-, (E)- and (Z)-3-(2-methoxyphenyl)-2-phenyl- and (E)-2-(2-methoxyphenyl)-3-phenyl-propenoic acids] have been protonated in fluorosulfonic acid at -78 degrees C, Protonation of the carboxylic group and a second protonation on the methoxy group at -78 degrees C or the ring bearing the methoxy group at 0 degrees C have been observed by C-13 NMR spectroscopy Upon protonation (Z)-alpha-phenylcinnamic acid is transformed to a protonated indenol derivative, Dehydrative ring closure begins at -78 degrees C and goes to completion at 0 degrees C, Similar transformations of the other studied Z-acid are suppressed by the deactivating effect of the protonated methoxy group. Only protonation has been observed for the E-acids at -78 degrees C as well as 0 degrees C, Calculations at the HF/3-21G level provide the equilibrium structures of the corresponding cations, Results of IGLO/C-13 NMR shift calculations are in good agreement with the experimental findings

Characterization of Pt supported on commercial fluorinated carbon as cathode catalysts for Polymer Electrolyte Membrane Fuel Cell

Pt nanoparticles supported on carbon monofluoride (CFx), synthesized from H2PtCl6 using NaHB4 as a reducing agent has been investigated as a cathode electrocatalyst in fuel cells. Surface characterization, performed by transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD), shows a homogeneous distribution and high dispersion of metal particles. Kinetic parameters for the electrocatalyst are also obtained from the steady state measurements using a rotating disk electrode (RDE) in 0.5 M H2SO4 solution. Analysis by Koutecky–Levich equation indicates an overall 4 e− oxygen reduction reaction (ORR). Evaluation of the catalyst in single cell membrane electrode assemblies (MEAs) for proton exchange membrane based Direct Methanol Fuel Cell (DMFC) and H2 Fuel Cell at different temperatures and flows of O2 and Air are shown and compared against commercial Pt/C as the cathode electrocatalyst. Evaluation of Pt/CFx in H2 fed fuel cells shows a comparable performance against a commercial catalyst having a higher platinum loading. However, in direct methanol fuel cell cathodes, an improved performance is observed at low O2 and air flows showing up to 60–70% increase in the peak power density at very low flows (60 mL min−1).Fil: Viva, Federico Andrés. University of Southern California; Estados Unidos. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Olah, George A.. University of Southern California; Estados UnidosFil: Prakash, G.K. Surya. University Of Southern California; Estados Unido

Electrochemical reduction of CO 2 over Sn-Nafion ® coated electrode for a fuel-cell-like device

Commercially available Sn particles mixed with Nafion ® ionomer are used to prepare an electrode with a gas diffusion layer support in a manner similar to that in which fuel cell electrodes are prepared. Cyclic voltammetry is performed in aqueous NaHCO 3 (basic medium) on the electrode and the Tafel parameters are obtained and compared with a Sn metal disc and with a graphite disc coated with Sn powder. In addition, electrolysis is carried out potentiostatically, also in NaHCO 3 solution, at various potentials. The exchange current density on the Sn/gas diffusion layer electrode shows to be two orders of magnitude higher that on the metallic Sn disc. The maximum current density obtained during electrolysis is 27 mA cm -2 at -1.6 V vs. NHE, with 70% faradaic efficiency towards the formation of formate, which is one of the highest values found in the literature on Sn electrode at ambient pressure. © 2012 Elsevier B.V. All rights reserved.Fil: Prakash, G.K. Surya. University Of Southern California; Estados UnidosFil: Viva, Federico Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University Of Southern California; Estados UnidosFil: Olah, George A.. University Of Southern California; Estados Unido

Direct one step preparation and 13C-NMR spectroscopic characterization of a-ferrocenyl carbocations derived from ferrocene and carbonyl compounds in trifluoroacetic acid medium1a

Reaction of aldehydes and ketones with ferrocene, in the presence of trifluoroacetic acid, afforded a series of stable long lived alpha-ferrocenylalkyl carbocations which were characterized by 13C-NMR spectroscopy. When this reaction was attempted using tetraphenylcyclopentadienone, quite unexpectedly the corresponding dihydro derivative 3 was isolated, in very good yield. Formation of this compound may require ferrocene acting as a reducing agent