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N. V. Smirnova, E. A. Astafiev
Electrochemical reduction of a-phenylvinylphosphonic acid on
the rotating palladium electrode
Abstract
The reduction of
phenylvinylphosphonic acid (PVPA) was investigated by the method of rotating
disk electrode on palladized platinum. The process occurs in the field of
potentials of hydrogen adsorption and formation of the a-phase of palladium
hydride at the deffusion reaction control. Kinetic currents of PVPA reduction
nonlinearly depend on the reagent concentration (1-25mM) in the whole potential
range. The magnitudes of hydrogenation rates under stationary and nonstationary
conditions were compared In first case the first order of reaction with respect
to the reagent was found. The rate of
the process is reduced when accumulation of adsorption products takes place.
The analysis of curves of potential shifts after the addition of the reagent at
open circuit after the polarisation current has reached a steady-state value,
were accomplished. The current of PVPA reduction substantially decreases and
does not depend on the velocity of electrode rotation in the presence of
cadmium adatoms. The features of such polarisation curves are probably caused
by the specifics of coadsorption of Cd2+ and sulfate anions.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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