Electrochemistry and Electrochemical Engineering

284 Pages·2017·5.82 MB·English

Electrochemistry
and Electrochemical
Engineering
Lenny Hart
Electrochemistry and
Electrochemical
Engineering

Electrochemistr y and
Electrochemical
Engineering
Edited by
Lenny Hart
Electrochemistry and Electrochemical Engineering
Edited by Lenny Hart
ISBN: 978-1-9789-0650-1
© 2018 Library Press
Published by Library Press,
5 Penn Plaza,
19th Floor,
New York, NY 10001, USA
Cataloging-in-Publication Data
Electrochemistry and electrochemical engineering / edited by Lenny Hart.
p.cm.
Includes bibliographical references and index.
ISBN 978-1-9789-0650-1
1.Electrochemistry. 2. Electrochemical analysis. 3. Electrochemistry, Industrial.
I. Hart, Lenny.
QD553 .E44 2018
541.37--dc23
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Table of Contents
Preface VII
Chapter 1 Introduction to Electrochemistry 1
i. Electrochemistry 1
ii. Electrochemical Engineering 22
Chapter 2 Branches of Electrochemistry 24
i. Photoelectrochemistry 24
ii. Bioelectrochemistry 27
iii. Quantum Electrochemistry 28
Chapter 3 Basic Elements of Electrochemistry 30
i. Electric Charge 30
ii. Electric Current 37
iii. Cathode 48
iv. Anode 55
v. Chemical Kinetics 60
Chapter 4 Devices used in Electrochemistry 67
i. Electrochemical Cell 67
ii. Galvanic Cell 69
iii. Thermogalvanic Cell 74
iv. Electrolytic Cell 76
v. Battery (Electricity) 79
vi. Salt Bridge 94
vii. Fuel Cell 96
viii. Galvanometer 120
ix. Photocathode 129
Chapter 5 Various Reactions and Processes in Electrochemistry 133
i. Galvanic Corrosion 133
ii. Galvanization 140
iii. Electrogalvanization 144
iv. Electroplating 147
v. Redox 154
vi. Organic Redox Reaction 165
vii. Electrochlorination 167
viii. Electrolysis 169
Chapter 6 Theory and Laws Related to Electrochemistry 179
i. Debye–Hückel Theory 179
ii. Paschen’s Law 185
iii. Faraday’s Laws of Electrolysis 192
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VI Contents
Chapter 7 Major Aspects of Electrochemistry 195
i. Electrode Potential 195
ii. Absolute Electrode Potential 198
iii. Standard Electrode Potential 200
iv. Molar Conductivity 202
v. Electrochemical Potential 205
vi. Volta Potential 207
Chapter 8 Corrosion: An Integrated Study 210
i. Corrosion 210
ii. Pitting Corrosion 225
iii. Intergranular Corrosion 228
iv. Crevice Corrosion 231
v. Microbial Corrosion 235
vi. Anodizing 237
vii. Cathodic Protection 246
viii. Corrosive Substance 256
Chapter 9 Evolution of Electrochemistry 260
Permissions
Index
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Preface
This book outlines the processes and applications of electrochemistry in detail.
It includes detailed explanation of the various concepts and uses of the subject.
Electrochemistry, as a branch of physical sciences, examines the relation between
electricity and the chemical changes caused by it. Electrochemical engineering deals
with the refining of metals as well as processes like electroplating. Such selected
concepts that redefine this subject area have been presented in the text. While
understanding the long-term perspectives of the topics, the book makes an effort in
highlighting their impact as a modern tool for the growth of the discipline. It will
serve as a reference to a broad spectrum of readers especially in the fields of chemical
engineering, material science and metallurgy.
To facilitate a deeper understanding of the contents of this book a short introduction
of every chapter is written below:
Chapter 1- The branch of physical chemistry that examines the relation between
electricity and chemical change is known as electrochemistry. The branch of
engineering which studies this is known as electrochemical engineering. The chapter
on electrochemistry offers an insightful focus, keeping in mind the complex subject
matter.
Chapter 2- Electrochemistry is an interdisciplinary subject. It spreads to other fields
as well, fields such as photoelectrochemistry, bioelectrochemistry and quantum
electrochemistry. The study of the interaction between light and electrochemical
systems is termed as photoelectrochemistry. Another branch of electrochemistry
that has been discussed is bioelectrochemistry; it concerns itself with topics like
cell membrane potentials and electrode reactions of redox enzymes. This section will
provide a glimpse of related fields of electrochemistry.
Chapter 3- Electric charge is the property of matter that makes it experience a force
when it is placed in an electromagnetic field. The basic elements of electrochemistry
are electric charge, electric current, cathode, anode and chemical kinetics. The
following chapter focuses on the important elements of electrochemistry, keeping in
mind the complex subject matter.
Chapter 4- A number of devices are used in electrochemistry. Some of these devices are
electrochemical cells, galvanic cells, thermogalvanic cells, electrolytic cells, fuel cells
and photocathodes. An electrochemical cell is a device that is capable of producing
electrical energy from chemical reactions whereas galvanic cells are electrochemical
cells that develop electrical energy from automatic redox reactions within a cell. This
section will provide an integrated understanding of electrochemistry.
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VIII Preface
Chapter 5- In order to stop iron or steel from rusting a coat of zinc is applied on
it. This process of applying zinc is known as galvanization. The process of bonding
steel to protect it from corrosion is termed as electrogalvaning. This chapter helps
the reader in understanding the various reactions and processes in electrochemistry.
Chapter 6- The theories and laws related to electrochemistry are Debye–Hückel
theory, Paschen’s law and Faraday’s law of electrolysis. Debye-Hückel theory
explains the departures from ideality in solutions of electrolytes and plasmas. The
topics discussed in the text are of great importance to broaden the existing knowledge
on electrochemistry.
Chapter 7- Electrochemistry is best understood in confluence with the major
topics listed in the following chapter. Some of these topics are electrode potential,
absolute electrode potential, standard electrode potential, molar conductivity and
electrochemical potential. This text helps the reader in developing an in-depth
understanding of the major aspects of electrochemistry.
Chapter 8- Corrosion is a process that occurs naturally, and helps in the conversion of
metal to chemically stable form. It is the slow demolition of materials by chemicals.
This section will provide an integrated understanding of corrosion.
Chapter 9- Electrochemistry, as a branch of study, has gone through several changes,
and has evolved over a number of decades. In recent times, electrochemistry has
become a part of the present study, including research in batteries and fuel cells.
The aspects elucidated in this chapter are of vital importance, and provide a better
understanding of electrochemistry.
Finally, I would like to thank the entire team involved in the inception of this book
for their valuable time and contribution. This book would not have been possible
without their efforts. I would also like to thank my friends and family for their
constant support.
Editor
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1
Introduction to Electrochemistry
The branch of physical chemistry that examines the relation between electricity and
chemical change is known as electrochemistry. The branch of engineering which stud-
ies this is known as electrochemical engineering. The chapter on electrochemistry of-
fers an insightful focus, keeping in mind the complex subject matter.
Electrochemistry
Electrochemistry is the branch of physical chemistry that studies the relationship
between electricity, as a measurable and quantitative phenomenon, and identifiable
chemical change, with either electricity considered an outcome of a particular chemical
change or vice versa. These reactions involve electric charges moving between elec-
trodes and an electrolyte (or ionic species in a solution). Thus electrochemistry deals
with the interaction between electrical energy and chemical change.
English chemist John Daniell (left) and physicist Michael Faraday (right), both credited as founders of
electrochemistry today.
When a chemical reaction is caused by an externally supplied current, as in electrol-
ysis, or if an electric current is produced by a spontaneous chemical reaction as in a
battery, it is called an electrochemical reaction. Chemical reactions where electrons are
transferred directly between molecules and/or atoms are called oxidation-reduction
or (redox) reactions. In general, electrochemistry describes the overall reactions when
individual redox reactions are separate but connected by an external electric circuit and
an intervening electrolyte.
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