Browsing by Author "Kanazirski I."

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    Kinetics of borohydride electrooxidation: Revisited
    (2014-01-01) Kalcheva S.; Kanazirski I.
    The initial steps of sodium borohydride oxidation are studied at PtAu alloy electrodes of Au bulk composition of 20, 40, 60 and 80 at. %. Linear sweep voltammetry is applied at low scan rates in 0.01 M NaBH4 in 1.00 M NaOH. The experiments are performed at four temperature values in the range from 293.2 K to 323.2 K. The data obtained are compared to those referring to Pt and Au as well. The values of the exchange current density and the total number of electrons exchanged are determined following the effect of the temperature applied. The activation energy for the exchange current density is found dependent on the bulk composition of the alloys studied. The lowest value is expected for an alloy of Au bulk content of ca 50 at. %. The dependence on the surface composition is only a tentative one in view of the sensitivity of the reaction studied. Its proceeding requires the presence of four adjacent active centers on the electrode surface whose heats of adsorption are strongly affected by the alloying.