Modern Aspects of Electrochemistry

351 Pages·1994·7.12 MB·English

by  V. A. Benderskii, A. N. Brodskii, L. I. Daikhin (auth.), B. E. Conway, J. O’M. Bockris

MODERN ASPECTS OF
ELECTROCHEMISTRY
No. 26
LIST OF CONTRIBUTORS
V. A. BENDERSKII V.PIZAK
A. N. Frumkin Institute of Center for Solar Energy and Hydrogen
Electrochemistry and Institute of Energy Research
Problems of Chemical Physics Fachbereich ECW
Russian Academy of Sciences D- 7000 Stuttgart 80, Germany
Moscow, Russia
R.W.REVIE
A. N. BRODSKII Metals Technology Laboratories
A. N. Frumkin Institute of Canada Centre for Mineral and Energy
Electrochemistry and Institute of Energy Technology
Problems of Chemical Physics Ottawa, Ontario, Canada K1A OGl
Russian Academy of Sciences
B. ROHLAND
Moscow, Russia
Center for Solar Energy and
BRIAN E. CONWAY Hydrogen Research
Department of Chemistry Fachbereich ECW
University of Ottawa D- 7000 Stuttgart 80, Germany
Ottawa, Ontario, Canada K1N 9B4
JAMES F. RUSUNG
LI.DAIKHIN Department of Chemistry
A. N. Frumkin Institute of University of Connecticut
Electrochemistry and Institute of Energy Storrs, Connecticut 06269-3060
Problems of Chemical Physics
Russian Academy of Sciences G. I. VEUCHKO
Moscow, Russia A. N. Frumkin Institute of
Electrochemistry and Institute of Energy
STOJAN S. DJOKIC Problems of Chemical Physics
Department of Chemistry Russian Academy of Sciences
University of Ottawa Moscow, Russia
Ottawa, Ontario, Canada K1N 9B4
H. WENDT
]>resent address: Sherritt Gordon Ltd.
Institute for Chemical Technology of
Fort Saskatchewan, Alberta,
TH Darmstadt
Canada TSL 2P2
D-6100 Darmstadt, Germany
JAMES H. UNDSAY
Physical Chemistry Department
Research and Environmental Staff
General Motors Corporation
THOMAS J. O'KEEFE
Department of Metallurgical
Engineering
Materials Research Center
University of Missouri-Rolla
Rolla, Missouri 65401
A Continuation Order Plan is available for this series. A continuation order will bring delivery of
each new volume immediately upon publication. Volumes are billed only upon actual shipment. For
further information please contact the publisher.
MODERN ASPECTS OF
ELECTROCHEMISTRY
No. 26
Edited by
B. E. CONWAY
Department of Chemistry
University of Ouawa
Ouawa, Ontario, Canada
J. O'M. BOCKRIS
Department of Chemistry
Texas A&M University
College Station, Texas
and
RALPH E. WHITE
Department of Chemical Engineering
University of South Carolina
Columbia, South Carolina
SPRINGER SCIENCE+BUSINESS MEDIA, LLC
The Library of Congress cataloged the first volume of this title as follows:
Modern aspects of electrochemistry. no. [1]
Washington Butterworths, 1954-
v. iIlus., 23 cm.
No. 1-2 issued as Modern aspects series of chemistry.
Editors: no. 1- J. Bockris (with B. E. Conway, No. 3-
Inprint varies: no. 1, New Yark, Academic Press. -No. 2, London, Butterworths.
1. Electrochemistry - Collected works. 1. Bockris, John O'M.ed. II. Conway, B. E.
ed. (Series: Modern aspects series of chemistry)
QD552.M6 54-12732 rev
ISBN 978-1-4899-1735-5 ISBN 978-1-4899-1733-1 (eBook)
DOI 10.1007/978-1-4899-1733-1
© 1994 Springer Science+Business Media New York
Originally published by P1enum Press, New York in 1994
Softcover reprint of the hardcover 1s t edition 1994
Ali rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, ar otherwise, without written permission from the Publisher
Preface
The present volume presents six chapters, two of them fairly brief,
covering both fundamental and applied electrochemistry. The
latter aspect has, of course, historical significance in the subject
as well as a major technological profile in recent decades, while
intimate connections between these complementary facets of the
subject have always been a driving force for its earlier and continu-
ing development.
In the Modern Aspects of Electrochemistry series we have
periodically included contributions from the several schools of
Russi~n electrochemistry. This approach is continued in the present
volume by inclusion of the chapter by Benderskii, Brodskii,
Daikhin, and Velichko from the Frumkin Institute, Moscow, on
phase transitions among molecules adsorbed in the double-layer
interphase at electrodes. This topic has attracted attention for some
years through the works of the Russian school and of Gierst and
Buess-Herman. Such behavior is also related to the important
phenomenon of self-assembly of molecules in films at interfaces. In
Chapter 1, these authors give an account of the factors associated
with two-dimensional phase transitions and associated orientation
effects with polar adsorbates at electrode interfaces. The theoretical
interpretation of these effects are also treated in some detail.
Chapter 2, by Rusling, deals with electrochemistry and electro-
catalysis in microemulsions, thus connecting aspects of electrode
kinetics, adsorption at electrode interfaces, and colloid chemistry.
It is shown how coulombic and hydrophobic interactions with
micelles can stabilize ion radicals produced at electrodes, and that
micelles in solution or adsorbed on electrodes can control kinetics
v
Preface
of bimolecular reactions between an electrochemically generated
mediator and a reactive substrate. The processes involved on a
microscale are reminiscent of and, in fact, related to "phase-transfer
catalysis" and represent an interesting and newly developing area in
electrochemistry.
Plzak, Rohland, and Wendt, in Chapter 3, give an overview
of the technological advances in development of state-of-the-art
hydrogen fuel cells and water electrolyzers that have taken place in
recent years. This chapter contains much useful comparative infor-
mation on construction and performance of various types of fuel
cells, from low-temperature aqueous systems to high-temperature
solid oxide types. The economic aspects also receive attention in
this authoritative contribution.
One of the most important electrochemical technologies for
surface treatment of metals and prevention of their corrosion is the
process of "electrogalvanizing." In Chapter 4, Lindsay and O'Keefe
give a thorough practical description of this major technology,
covering such matters as process description, including the electro-
chemical processes, use of pure zinc and zinc alloy coatings, and
the important aspect of corrosion of the zinc coatings. The authors
bring their practical experience in this field to bear in producing an
authoritative account of this area of applied electrochemistry.
In Chapter 5, Djokic and Conway review transient procedures
for examination of the electrode reactions in the Hall-Heroult
process for electrolytic production of aluminum metal, especially
at the carbon anode depolarized by discharge of oxide or oxy-
fluoride ions. The conditions are usually, but not always, diffusion-
controlled, as determined by the quantity of the Al20 3 reactive
solute in the cryolite melt. Hence, procedures based on analysis of
the diffusion problem are the main topic of this chapter, with
examination of complications arising from the application of
transient procedures in a very corrosive system at approximately
1050°C.
In Chapter 6 Revie deals with the electrochemical aspects of
environmental cracking of metals, a topic of major importance in
ferrous-metal structural engineering. Interesting aspects of this
contribution are the role of surfaces in mechanical properties of
metals in relation to movements of dislocations, electrochemistry
of stressed surfaces, and the role of "poisons" in promoting H
Preface vii
entry into metals undergoing corrosion, with resulting hydrogen
embrittlement. The important areas of stress-corrosion cracking
and corrosion-fatigue effects are also reviewed.
Brian E. Conway
University of Ottawa
John O'M. Bockris
Texas A&M University
Ralph E. White
University of South Carolina
Contents
Chapter 1
PHASE TRANSITIONS IN THE DOUBLE LAYER
AT ELECTRODES
V. A. Benderskii, A. N. Brodskii, L. I. Daikhin,
and G. I. Velichko
I. General Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
II. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
III. Phase Transitions in Open Adsorption Systems . . . . . . . 6
IV. Phase Transitions in Monolayers of Water
Molecules Adsorbed on Electrode Surfaces . . . . . . . . . . . 16
V. The Possibility of Observation of Surface
Reconstruction of Transition Metals in Contact
with Electrolytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
VI. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Appendix. Measurements of Laser-Induced
Temperature Jump Effects . . . . . . . . . . . . . . . . . . . 41
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Chapter 2
ELECTROCHEMISTRY AND ELECTROCHEMICAL
CATALYSIS IN MICRO EMULSIONS
James F. Rusling
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
II. Structures and Properties of Microemulsions . . . . . . . . . 51
ix
x Contents
1. Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2. Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3. Kinetics of Chemical Reactions . . . . . . . . . . . . . . . . . . 56
4. Adsorption of Surfactants on Charged Surfaces . . . . 58
III. Electrochemistry in Microemulsions . . . . . . . . . . . . . . . . 65
1. Diffusion Studies in Conductive Microemulsions . . . 65
2. Diffusion in wfo Microemulsions................. 72
3. Electrochemical Reactions . . . . . . . . . . . . . . . . . . . . . . 75
IV. Electrochemical Catalysis in Microemulsions . . . . . . . . . 85
1. Micellar Media-A Summary . . . . . . . . . . . . . . . . . . . 85
2. Reduction of Vicinal Dihalides in wfo Micro-
emulsions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
3. Reduction of Aliphatic Halides in Bicontinuous
Microemulsions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
4. Bulk Dechlorinations of Polychlorinated Biphenyls 97
V. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Chapter 3
ADVANCED ELECTROCHEMICAL HYDROGEN
TECHNOLOGIES: WATER ELECTROLY ZERS AND
FUEL CELLS
V. Plzak, B. Rohland, and H. Wendt
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
II. Alkaline Water Electrolysis . . . . . . . . . . . . . . . . . . . . . . . . 109
1. Conventional Electrolysis . . . . . . . . . . . . . . . . . . . . . . . 109
2. Development of Advanced Alkaline Electrolyzers . . . 114
3. Innovations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
III. Electricity Generation by Fuel Cells . . . . . . . . . . . . . . . . 130
1. Theoretical Thermal Efficiency of Fuel Cell
Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
2. Characteristics of Different Fuel Cell Technologies 132
3. Structure of Fuel Cells and Their Components . . . . 134
4. Components of Fuel Cells with Liquid
Electrolytes and Their Respective Structures . . . . . . 135