Tempature-Programmed Reduction for Solid Materials Characterization PDF

PREFACE

Temperature-programmed reduction (TPR) is a relatively new technique used for the characterization of solid materials. Since the first publication in this area (1975), many papers have appeared in the literature that have shown its applicability in a variety of scientific fields, most particularly in characterization of catalysts. In 1982 the first review on the subject of TPR appeared in Catalysis Reviews.

The technique, based on the reducibility of species in solids, enables one to obtain information not only of a purely analytical nature but also, and more importantly, about the condition of species present in and on solids. At the same time, the technique is relatively simple in concept and application. It involves very low capital investment relative to more sophisticated techniques used in the above area.

As a result, TPR and related techniques are now becoming commonly used weapons in the scientist's armory for the characterization of solids. This applies across 'the whole spectrum of academic and industrial research. It is thus timely that the first book should appear that represents not only the state of the art of the technique, but also recent developments and future trends.

The book is intended as an informative guide to both experts and initiates in the field. The principles and theory of isothermal and dynamic reducibility (TPR) are discussed in full detail, together with a clear description of the parametric sensitivity of the technique (Chapter 2). Chapter 3 describes the instrumentation that has been used for the measurement of TPR. Chapter 4 fully discusses the areas where the technique has found application in such a way that the reader should gain ready knowledge of the current state of the art and the possible advantages and disadvantages of the technique in comparison with other techniques. Finally, in Chapter 5 the developing trends in temperature programming are discussed. Here we are concerned with not only TPR but temperature-programmed reactions in general. This chapter attempts to point the direction in which temperature-programming techniques for the characterization of materials are heading.

This volume is aimed at a wide audience, including academics (undergraduate, postgraduate and university staff), research scientists, and technologists in industry and research institutes concerned with the manifold problems involving characterization of solids in such fields as heterogeneous catalysis, materials science/metallurgy, and analytical chemistry.

The terminology used in this and related fields has led to some confusion; in particular, the acronym TPR has been used to refer to both temperature-programmed reduction and temperature- programmed reaction. We would recommend and have used throughout this work the abbreviation TPR to refer to temperature-programmed reduction. Where reference is made to temperature-programmed reaction the expression is written in full. Abbreviations relating to specific temperature-programmed reactions present, so far, no ambiguity and we have recommended the following:

Temperature-programmed oxidation (TPO)

Temperature-programmed sulfidation (TPS)

Temperature-programmed carburization (TPC)

Temperature-programmed methanation (TPM)

We would like to thank Drs. S. J. Gentry and N. W. Hurst of the Health and Safety Executive, who have done much pioneering in this field and did much of the groundwork necessary for the preparation of this work. We have drawn freely from the original review article, of which they were coauthors, in the preparation of this book. We would also like to thank Mr. I. Kitchener of the London Research Station of British Gas for providing us with advice on optimizing conditions for TPR. Finally, thanks are due to all the scientists who provided details of their work for inclusion in the book and permission to reproduce diagrams.

Author: Alan Jones