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Book Review In-Situ Spectroscopy in Heterogeneous Catalysis Edited by James Haw.

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molecular machines. These studies indicate that synthetic organic chemistry
may contribute to the miniaturization of
components such as transistors for computers of the future. Molecules (or, more
accurately, aggregates) with switching
capability are already available, having
structures based on rotaxanes or catenanes. However, attaching these to solid
substrates to construct integrated circuits will require much further development work.
The last two chapters, by Maitra and
Balasubramanian and by Bond and
Jones, are concerned with supramolecular aspects of molecular crystals. The
work in this area involves the methods
of ™crystal engineering∫, in other words
using weak interactions in molecular
crystals to control the arrangement of
the molecules in the crystal. Interestingly, Chapter 11 cites a dictionary
definition of a ™material∫ as ™any substance out of which something is, or may
be, made∫ (p. 363). Scientists or engineers working on applications of materials would certainly find that too broad
a definition and would substitute a more
restricted one.
To summarize, this is an excellent
book which has been written by competent authors and contains a wealth of
good illustrations. It is primarily suitable
for chemists, but physicists and materials
scientists will also find much interesting
and stimulating material in it. It can be
recommended for everyone whose work
is concerned with the latest developments in the science of materials.
Matthias Epple
Anorganische Chemie
Universit‰t Bochum (Germany)
In-Situ Spectroscopy in
Heterogeneous Catalysis
Edited by James Haw.
Wiley-VCH, Weinheim
2002. 276 pp., hardcover E 109.00.–ISBN
3-527-30248-4
Because of the necessity to study heterogeneous catalysts ™at work∫, in situ
256
methods have developed considerably
in the past few decades, and the field
appears ready for a comprehensive
overview. The book In-Situ Spectroscopy in Heterogeneous Catalysis, edited by
James Haw, is a collection of individual
articles on selected methods (not all of
them spectroscopies), written by specialists. The intent is to ™introduce
young scientists with training in diverse
areas∫ to heterogeneous catalysis research.
In his introduction the editor briefly
addresses the present limitations–pressure gap, materials gap, spectator species–and the impact of theory, and he
uses these issues to refer to each of the
chapters. Haw also attempts to define
™in situ∫. This section is called ™compromises∫, and accordingly the author
allows not only the ™purest definition∫
but also a pragmatic approach in which
he reduces ™in situ∫ to any study that
™teaches us about the chemistry ... under
reaction conditions∫.
All the articles have a similar structure. After an introduction to the technique a number of examples are provided. One issue is certainly how far such a
book should address the principles of the
techniques themselves. This is resolved
quite well, in that only the more exotic
techniques that are not covered in textbooks are introduced at length. A plus is
the consistent level of difficulty of the
articles. The experimentalist interested in
technical details must generally resort to
the secondary literature.
Graphs with schemes of setups or
experimental data are abundant and
make a large contribution to the quality
of the book; mostly they are well
reproduced and labeled. The extensive
use of subheadings in all chapters is very
useful, and all of these subheadings are
reproduced in the table of contents,
which thus gives a clear picture of the
structure of the articles. The table of
contents provides a better means of
finding something specific in the book
than does the index, which is characterized by mistakes and repetitions of
terms with slight variations.
The book starts with a chapter on
surface science. Its first part is dedicated
to sum frequency generation (SFG) and
nicely demonstrates the power of a true
in situ experiment, showing plots in
which catalytic and spectroscopic data
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1433-7851/03/4203-0256 $ 20.00+.50/0
(from CO oxidation on Pt) are correlated. The second part of this chapter, on
STM (scanning transmission microscopy), deals with adsorbed species rather
than actual catalysis, but brings up an
important subject, that of processes
induced by the experiment itself (™tipinduced catalysis∫).
The chapter written by the editor
presents an enlightening overview of the
ways to employ NMR spectroscopy for
in situ studies in catalysis. The most
suitable nucleus that can be probed, and
thus the focus of interest, is 13C, which
delivers information on surface species
and products, not on changes of the
catalyst itself. The examples show the
tedious and often indirect approach of
this method. The author is very honest
about its limitations, admitting that
™[NMR] cannot work alone∫; which also
applies to most of the techniques, and
follows this up with an example where
an additional technique provides complementary information.
The chapter on theory gives an
overview of the principles of different
methods, leading to a tour through the
acronyms of theoretical chemistry. A
definite strength is the vast list of
references. The examples are all from
the field of acid ± base catalysis, are all
based on cluster models, and compare
the calculated energies (activation, adsorption) or NMR isotropic shifts with
experimental results.
The Raman spectroscopy chapter is
focussed on the author×s experimental
setup (UV/Raman) and work. While the
challenges of an in situ Raman application are laid out clearly, the examples
(one of which is not from the field of
catalysis) fail to demonstrate the benefits of an in situ over an ex situ experiment; they concern the nature of coke
on a zeolite and the decomposition of
lubricants upon grinding with different
tools.
The XAS chapter emphasizes technique and selected aspects thereof.
Some recent developments in cells are
not mentioned, nor are the important
rapid and dispersive XAS techniques.
The complications of the data analysis
remain sketchy and the examples are
extremely condensed. An interesting
approach to the application of in situ
techniques to monitor catalyst preparation is mentioned briefly.
Angew. Chem. Int. Ed. 2003, 42, No. 3
Angewandte
Chemie
A detailed introduction to the applications of positron emission for in situ
research is followed by a description of
the study of axial concentration profiles
in flow reactors. This longest chapter of
the book includes details of the mathematical modeling of data on concentration profiles in a powder bed.
The IR and the TAP (temporal
analysis of products) chapters are informative and fun to read. A variety of IR
techniques, among them again SFG, is
presented including descriptions of cell
constructions. The examples are diverse,
and show the strengths and limitations
Angew. Chem. Int. Ed. 2003, 42, 255 ± 257
of the IR method very well. The TAP
chapter captivates through its structure
and clarity; it covers all aspects from
types of experiments to analyzing the
data.
It remains unclear why certain spectroscopies such as UV/Vis or EPR, and
surface science methods such as XPS
that are inching into interesting pressure
ranges, as well as environmental microscopy, have been entirely omitted and are
not even mentioned in the introductory
overview. A chapter compiling information on all techniques, such as the
accessible temperature and pressure
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ranges, sensitivity, time resolution etc.,
in the form of a few tables to allow a
critical comparison, would have set the
book above the level of review articles
on single methods. Nevertheless, the
book offers interesting material for any
researcher with a background in catalysis and also for the specialist who wants
to extend his or her knowledge.
Friederike Jentoft
Fritz Haber Institute of the
Max Planck Society
Berlin (Germany)
1433-7851/03/4203-0257 $ 20.00+.50/0
257
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