http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Some studies on electron transfer theory and a theoretical study of electrochemical reduction of oxygen on platinum
xiv, 143 leaves : illustrations ; 28 cm.
This work consists of two parts. In the first part, the
effect of the potential energy function on the charge
transfer theory was studied. Use of a harmonic potential in
the potential energy distance relations for charge transfer
reactions at electrodes predicts nonlinear Tafel lines and an
inverted region for current-potential relations which are in
disagreement with well established experimental laws, well
known for electron and ion transfer reactions. The inverted
region was analyzed in terms of harmonic and Morse type
potential energy profiles. Tafel linearity is known
(experimentally) to extend over more than 0.6 V for redox
reactions and 1.2 V for hydrogen and oxygen evolution; it
does not exceed 0.2 V using the harmonic potential energy -
distance relations. Qualitatively, an inverted region can
not be obtained if a realistic Morse type anharmonic
potential energy profile is used. The constant value of the
reorganization energy used in interpreting the experimental
data to represent the inverted region needs revision. Non-
linear Tafel plots for organic spacer covered electrodes can
be interpreted in terms of resonance tunneling of the
electron across the barrier in the spacer layer. In the
second part of this work a theoretical study of
electrochemical reduction oxygen on platinum was carried out.
In this latter work, multi-dimensional potential energy
surfaces were constructed for the experimentally found most
probable rate-determining step in electroreduction of oxygen
(ERO) on Pt(I II) and Pt(I 00) using a combination of
experimental data in Morse functions and ASED-MO, a semi-
empirical quantum mechanical technique. The minimum energy
path for the reaction was extracted by Euler's single step
method. The non-adiabacity of the electron transfer step was
treated with Landau-Zener formalism and the proton tunneling
was taken into account using an Eckart barrier. On this
basis, the kinetic parameters, e.g., the activation energies,
entropies of activation, the symmetry factors and reaction
rates of the model reaction, were calculated.
Issued also on microfiche from University Microfilms Inc.
Includes bibliographical references: pages 113-123.