Photocatalysis: Fundamentals and Perspectives (RSC Energy and Environment, 14, Band 14) - Hardcover

 
9781782620419: Photocatalysis: Fundamentals and Perspectives (RSC Energy and Environment, 14, Band 14)
Hardcover
ISBN 10: 1782620419 ISBN 13: 9781782620419
Verlag: Royal Society of Chemistry, 2016

Inhaltsangabe

Combining the basic concepts of photocatalysis with the synthesis of new catalysts, reactor and reaction engineering, this book provides a comprehensive resource on the topic. The book introduces the fundamental aspects of photocatalysis including the role of surface chemistry and understanding the chemistry of photocatalytic processes before exploring the theory and experimental studies of charge carrier dynamics. Specific chapters then cover new materials for the degradation of organics; water splitting and CO2 reduction; as well as reactor and reaction engineering. Researchers new to this discipline can learn the first principles, whilst experienced researchers can gain further information about aspects in photocatalysis beyond their area of expertise. Together with Photocatalysis: Applications, these volumes provide a complete overview to photocatalysis.

Die Inhaltsangabe kann sich auf eine andere Ausgabe dieses Titels beziehen.

Über die Autorin bzw. den Autor

Detlef Bahnemann is a Professor at the Institute for Technical Chemistry, Gottfried Wilhelm Leibniz University of Hannover, Germany, and Director of the Laboratory for Photoactive Nanocomposite Materials at Saint-Petersburg State University, Russia. He has worked in the field of photocatalysis for over 30 years.

Jenny Schneider is a Researcher at the Institute for Technical Chemistry, Gottfried Wilhelm Leibniz University of Hannover, Germany. She is a specialist in time-resolved investigations of photocatalytic processes.

Jinhua Ye is Managing Director for the Photo-Catalytic Materials Center (PCMC) at the National Institute for Materials Science, Japan. Her research is dedicated to developing new photocatalytic materials for environment preservation.

Gianluca Li Puma is Professor of Chemical and Environmental Engineering at Loughborough University, UK. He is an expert in reaction and reactor engineering, including photochemical and photocatalytic systems.

Dionysios D. Dionysiou is a Professor in the Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, USA. He has over 20 years of experience in the field of photocatalysis.

Von der hinteren Coverseite

Combining the basic concepts of photocatalysis with the synthesis of new catalysts, reactor and reaction engineering, this book provides a comprehensive resource on the topic.

The book introduces the fundamental aspects of photocatalysis including the role of surface chemistry and understanding the chemistry of photocatalytic processes before exploring the theory and experimental studies of charge carrier dynamics. Specific chapters then cover new materials for the degradation of organics; water splitting and CO2 reduction; as well as reactor and reaction engineering. Researchers new to this discipline can learn the first principles, whilst experienced researchers can gain further information about aspects in photocatalysis beyond their area of expertise.

Together with Photocatalysis: Applications, these volumes provide a complete overview to photocatalysis.

Aus dem Klappentext

Combining the basic concepts of photocatalysis with the synthesis of new catalysts, reactor and reaction engineering, this book provides a comprehensive resource on the topic.

The book introduces the fundamental aspects of photocatalysis including the role of surface chemistry and understanding the chemistry of photocatalytic processes before exploring the theory and experimental studies of charge carrier dynamics. Specific chapters then cover new materials for the degradation of organics; water splitting and CO2 reduction; as well as reactor and reaction engineering. Researchers new to this discipline can learn the first principles, whilst experienced researchers can gain further information about aspects in photocatalysis beyond their area of expertise.

Together with Photocatalysis: Applications, these volumes provide a complete overview to photocatalysis.

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Photocatalysis

Fundamentals and Perspectives

By Jenny Schneider, Detlef Bahnemann, Jinhua Ye, Gianluca Li Puma, Dionysios D. Dionysiou

The Royal Society of Chemistry

Copyright © 2016 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-1-78262-041-9

Contents

Part 1: Fundamental Aspects of Photocatalysis, 
Chapter 1 Photoelectrochemistry: From Basic Principles to Photocatalysis Laurence M. Peter, 3, 
Chapter 2 Understanding the Chemistry of Photocatalytic Processes Amer Hakki, Jenny Schneider, and Detlef Bahnemann, 29, 
Chapter 3 Current Issues Concerning the Mechanism of Pristine TiO2 Photocatalysis and the Effects on Photonic Crystal Nanostructures Cecilia B. Mendive, Mariano Curti, and Detlef Bahnemann, 51, 
Chapter 4 Specificity in Photocatalysis Yaron Paz, 51, 
Chapter 5 Photoexcitation in Pure and Modified Semiconductor Photocatalysts Gonu Kim, Yiseul Park, Gun-hee Moon, and Wonyong Choi, 110, 
Chapter 6 New Concepts in Photocatalysis Ying Wu and Michael Wark, 129, 
Part 2: Primary Processes in Photocatalysis, 
Chapter 7 Kinetic Processes in the Presence of Photogenerated Charge Carriers Yoshio Nosaka and Atsuko Y. Nosaka, 165, 
Chapter 8 Traps and Interfaces in Photocatalysis: Model Studies on TiO2 Particle Systems Thomas Berger and Oliver Diwald, 
Chapter 9 Interplay Between Physical and Chemical Events in Photoprocesses in Heterogeneous Systems Alexei V Emeline, Vladimir K. Ryabchuk, Vyacheslav N. Kuznetsov, and Nick Serpone, 218, 
Part 3: New Materials, 
Chapter 10 New Materials: Outline Jinhua Ye, 247, 
Chapter 11 New Materials for Degradation of Organics Shuxin Ouyang and Hua Xu, 252, 
Chapter 12 New Materials for Water Splitting Kazuhiko Maeda, 295, 
Chapter 13 New Materials for CO2 Photoreduction Yong Zhou, Wenguang Tu, and Zhigang Zou, 318, 
Part 4: Reactor and Reaction Engineering, 
Chapter 14 Fundamentals of Radiation Transport in Absorbing Scattering Media Orlando M. Alfano, Alberto E. Cassano, Javier Marugan, and Rafael van Grieken, 351, 
Chapter 15 Photocatalytic Reactor Design Javier Marugan, Rafael van Grieken, Alberto E. Cassano, and Orlando M. Alfano, 367, 
Chapter 16 Photocatalytic Reactor Modeling Fiderman Machuca-Martinez, Miguel Angel Mueses, José Colina-Marquez, and Gianluca Li Puma, 388, 
Subject Index, 425,


CHAPTER 1

Photoelectrochemistry: From Basic Principles to Photocatalysis

LAURENCE M. PETER



1.1 Introduction

The foundations of semiconductor photoelectrochemistry were laid by Gerischer, Pleskov, Memming, Bard and others in the 1960s. Several authoritative texts are available that summarize the basic concepts. At this time, the physics and chemistry of light-driven reactions at semiconductor surfaces were studied extensively using well-defined bulk monocrystalline materials. Interest in semiconductor photoelectrochemistry became more widespread following the 1973 oil crisis, which stimulated an urgent search for alternative energy technologies. During this period, several efficient liquid-junction solar cells were developed that utilized (mainly single crystal) semiconductors in contact with redox electrolytes. Examples of materials that were studied include CdS, CdSe, GaAs, GaP, InP, WSe and MoSe2 (see Morrison for an excellent literature survey for this period). However, problems of long-term stability and high costs led ultimately to a lessening of activity in the area. The possibility of using illuminated semiconductor/electrolyte junctions to split water was also recognized at this time, and the much-cited Nature paper by Fujishima and Honda marked the beginning of a sustained search for stable semiconductors that can split water using visible light. Again, the initial enthusiasm declined when faced with the stringent demands for high efficiency combined with long-term chemical stability.

Semiconductor photoelectrochemistry experienced a renaissance stimulated by the development of mesoporous dye-sensitized solar cells following the 1991 Nature paper of O'Regan and Grätzel. The resulting move away from well-defined single crystal bulk materials to high surface area nanostructured electrodes opened a new field of research, and many of the ideas that had been developed for bulk semiconductor electrodes required re-examination in view of the very different length scales. Nanostructured semiconductor electrodes are now also being utilized for light-driven water splitting and environmental remediation. This historical development has resulted in a convergence of the fields of semiconductor photoelectrochemistry and photocatalysis at semiconductor particles. The objective of this chapter is to review the basic ideas that were developed originally to understand the photoelectrochemical behaviour of bulk semiconductors and to see how these ideas need to be modified when considering nanostructured semiconductor electrodes and dispersed colloidal systems.


1.2 A Brief Summary of Semiconductor Physics

The band model of solids' leads to the diagram shown in Figure 1.1, which is the starting point for the construction of band diagrams for p-n and metal-semiconductor junctions as well as semiconductor-electrolyte junctions. An important quantity shown in Figure 1.1 is the Fermi energy, EF, which is a measure of the free energy of electrons.

The semiconductor in Figure 1.1 is doped n-type by the presence in the crystal lattice of donor atoms that can be ionized at room temperature, releasing electrons to vacant levels in the conduction band. The concentration of electrons in the conduction band under conditions of thermal equilibrium is given by the Fermi-Dirac equation:

[MATHEMATICAL EXPRESSION OMITTED] (1.1a)

where Nc is the density of states in the conduction band. For normal levels of doping (<1018 cm-3), the exponential term in eqn (1.1a) is much larger than unity, so that the electron density can be approximated by the Boltzmann equation:

[MATHEMATICAL EXPRESSION OMITTED] (1.1b)

It follows that the Fermi energy shown in Figure 1.1 indicates the type and level of doping. The higher the n-doping, the closer EF is to the conduction band. In the case of p-type doping, electron acceptors in the crystal lattice accept electrons from the occupied valence band, creating holes. The concentration of holes under thermal equilibrium conditions is given by:

[MATHEMATICAL EXPRESSION OMITTED] (1.2a)

and for normal doping levels:

[MATHEMATICAL EXPRESSION OMITTED] (1.2b)

It follows that the Fermi level in p-type semiconductors lies close to the valence band. Regardless of the type of doping, the product of the equilibrium concentrations of electrons and holes is given by the law of mass balance:

[MATHEMATICAL EXPRESSION OMITTED] (1.3)

where ni is the intrinsic electron density for the undoped case where electrons and holes are only produced by thermal excitation of electrons across the gap, so that n = p.

Notably, EF is equivalent to the electrochemical potential of electrons. This means that it is a free energy that depends not only on concentration (via the temperature x entropy term in the Gibbs free energy G = U + PV-TS) but also on electrical potential. By contrast, Ec and Ev are internal energy terms that correspond to the standard states for electrons and holes, respectively. For a lucid discussion of the thermodynamics of the Fermi energy, the reader is referred to the...

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Verlag
Royal Society of Chemistry
Erscheinungsdatum
2016
Sprache
Englisch
ISBN 10 
1782620419
ISBN 13 
9781782620419
Einband
Gebundene Ausgabe
Auflage
1
Anzahl der Seiten
436
Herausgeber
Schneider Jenny, Bahnemann Detlef, Ye Jinhua, Li Puma Gianluca, Dionysiou Dionysios D.
Kontakt zum Hersteller
Nicht verfügbar
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