Spectroelectrochemistry: Theory and Practice

ISBN-13: 9781461282785 / Angielski / Miękka / 2012 / 468 str.

Robert J. Gale; Robert J. Gale

Opis

The intention of this monograph has been to assimilate key practical and theoretical aspects of those spectroelectrochemical techniques likely to become routine aids to electrochemical research and analysis. Many new methods for interphasial studies have been and are being developed. Accordingly, this book is restricted in scope primarily to in situ methods for studying metal electrolyte or semiconductor electrolyte systems; moreover, it is far from inclusive of the spectroelectrochemical techniques that have been devised. However, it is hoped that the practical descriptions provided are sufficiently explicit to encourage and enable the newcomer to establish the experimental facilities needed for a particular problem. The chapters in this text have been written by international authorities in their particular specialties. Each chapter is broadly organized to review the origins and historical background of the field, to provide sufficiently detailed theory for graduate student comprehension, to describe the practical design and experimental methodology, and to detail some representative application examples. Since publication of Volume 9 of the Advances in Electrochemistry and Electrochemical Engineering series (1973), a volume devoted specifically to spectroelectrochemistry, there has been unabated growth of these fields. A number of international symposia-such as those held at Snowmass, Colorado, in 1978, the proceedings of which were published by North-Holland (1980); at Logan, Utah in 1982, published by Elsevier (1983); or at the Fritz Haber Institute in 1986-have served as forums for the discussion of nontraditional methods to study interphases and as means for the dissemination of a diversity of specialist research papers.

Spis treści

1. Introduction.- 1. Motivations for Spectroelectrochemistry.- 2. Methodologies Available.- 3. Computer-Based Data Processing.- 4. The Future.- References.- 2. X-Ray Techniques.- 1. Historical Background.- 1.1. Ultrahigh Vacuum Techniques.- 1.2. X-Ray Techniques for Surface Study.- 1.2.1. Scattering Methods.- 1.2.2. Absorption Techniques.- 1.3. Neutron Scattering.- 2. Theory—The Interaction of X-Rays with Matter.- 2.1. X-Ray Scattering.- 2.2. X-Ray Absorption.- 3. Experimental Details.- 3.1. In Situ X-Ray Diffraction.- 3.1.1. X-Ray Detection Methods.- 3.1.2. X-Ray Sources.- 3.1.3. Cell Design.- 3.1.4. The Experiment.- 3.2. In Situ X-Ray Absorption Studies.- 4. Applications.- 4.1. In Situ X-Ray Diffraction.- 4.2. EXAFS Studies.- List of Symbols.- References.- 3. Photoemission Phenomena at Metallic and Semiconducting Electrodes.- 1. Introduction.- 1.1. Some General Features of Photoelectronic Emission.- 1.2. Reaction Step Models for Photoemission.- 2. Theoretical: Metals.- 2.1. Fowler’s Theory for Metal/Vacuum Interfaces.- 2.2. Tunneling through the Potential Barrier.- 2.3. Quantum Mechanical Photoemission Theories for the Metal/Vacuum and Metal/Electrolyte Interfaces.- 2.4. Optical Polarization and Crystal Epitaxy Effects.- 2.5. Role of the Electrical Double Layer.- 3. Theoretical: Semiconductors.- 3.1. Kane’s Theory for Semiconductor/Vacuum Interfaces.- 3.2. Gurevich’s Quantum Mechanical $$ \frac $$ Law for In Situ Photoemission.- 3.3. Bockris and Uosaki Treatment.- 3.4. Hot Carrier Effects: The Nozik-Williams Model.- 4. Experimental Techniques.- 4.1. Choice of Scavanger and Electrolyte.- 4.2. Cell Design and Electrode Preparation.- 4.3. Optics, Apparatus, and Methods.- 5. Conclusions.- 5.1. Physical Mechanistic Studies.- 5.2. Solvated Electron Chemistry.- References.- 4. UV-Visible Reflectance Spectroscopy.- 1. Introduction.- 2. Physical Optics.- 2.1. Optical Constants.- 2.2. The Reflectivity of an Interface.- 2.3. Three-Phase System and Linear Approximation.- 2.4. Nonlocal Optics.- 3. Experimental.- 3.1. Arrangements for Determining ?R/R.- 3.2. Electrochemical Cells and Electrodes.- 4. The Metal/Electrolyte Interface.- 4.1. Electroreflectance Studies of the Metal Surface.- 4.2. Surface States at the Metal/Electrolyte Interface.- 4.3. Surface Plasmon Studies.- 4.4. Double-Layer Contributions to Electroreflectance.- 5. Chemisorption and Film Formation.- 5.1. Oxides.- 5.2. Ions and Molecules.- 5.3. Metal Adsorbates.- 5.4. Metal Film Formation.- 6. Summary and Outlook.- Appendix I.- Appendix II.- List of Symbols.- References.- 5. Infrared Reflectance Spectroscopy.- 1. Introduction and Historical Survey.- 2. Theory of Reflection-Absorption Spectroscopy.- 2.1. Propagation of an Electromagnetic Plane Wave.- 2.2. Fundamentals of Absorption Spectroscopy. Selection Rules.- 2.3. Specular Reflection. Application to Reflection-Absorption Spectroscopy. Surface Selection Rules.- 3. Experimental Techniques.- 3.1. Dispersive Spectrometers.- 3.1.1. Optical Components Used in Infrared Spectrometers Specially Designed for External Reflectance Spectroscopy.- 3.1.2. Signal Detection and Processing.- 3.1.3. Techniques for External Reflectance Spectroscopy.- 3.1.4. Internal Reflection Spectroscopy.- 3.2. Fourier Transform Infrared Spectroscopy (FTIRS).- 3.2.1. Principle of FTIR Spectrometers.- 3.2.2. Use for External Reflection Measurements.- 3.2.3. Use for Internal Reflection.- 3.3. Design of the Spectroelectrochemical Cell.- 3.3.1. Electrochemical Cells for External Reflection.- 3.3.2. Electrochemical Cells for Internal Reflection.- 3.4. Discussion of the Techniques.- 4. Applications to Selected Examples.- 4.1. General Survey.- 4.2. Adsorption of Hydrogen on Platinum in Acid Media.- 4.2.1. Why This Example?.- 4.2.2. Experimental Conditions and Data Acquisition.- 4.2.3. Interpretation of the Results.- 4.3. Adsorption of Carbon Monoxide on Noble Metals in Aqueous Media.- 4.3.1. Choice of This Example.- 4.3.2. Adsorption of CO on Platinum Electrodes.- 4.3.3. Adsorption of CO on Palladium.- 4.3.4. Infrared Bands of Adsorbed CO.- 4.4. Adsorbed Intermediates in Electrocatalysis.- 4.4.1. Chemisorption of Methanol at a Platinum Electrode.- 4.4.2. Chemisorption of Formic Acid at Platinum, Rhodium, and Gold Electrodes.- 4.4.3. Chemisorption of Ethanol at a Platinum Electrode.- 4.5. Investigations in Nonaqueous Solvents and Detection of the Intermediates Formed in the Vicinity of the Electrode Surface.- 4.5.1. Choice of Examples.- 4.5.2. Spectra of Adsorbed Species in Nonaqueous Media.- 4.5.3. Observation of Anion and Cation Radicals.- 5. Conclusions.- References.- 6. Surface-Enhanced Raman Scattering.- 1. Overview.- 1.1. Introduction.- 1.2. Light Scattering by Molecules.- 1.3. Characteristics of Surface Raman Scattering.- 1.4. The SERS Experiment.- 1.5. Active Sites and the Quenching of SERS.- 1.6. Metal-Molecule Complex.- 1.7. Theoretical Considerations.- 2. Experimental Methods.- 2.1. Introduction.- 2.2. Intensity of Detected Scattered Light.- 2.3. Laser Radiation Sources.- 2.4. Optical Setup and Depolarization Ratio Measurements.- 2.5. Electrochemical Cell, Instrumentation, and Pretreatment.- 2.6. The Monochromator and Detection System.- 3. Theory of the Electromagnetic Enhancement in SERS.- 3.1. The Electromagnetic Enhancement for Spherical Particles.- 3.1.1. Electrostatic Boundary Value Problem for a Metal Sphere.- 3.1.2. Enhancement Factors for a Spherical Geometry.- 3.2. The Electromagnetic Enhancement for a Prolate Metal Spheroid.- 3.2.1. Electrostatic Boundary Problem for a Prolate Metal Spheroid.- 3.2.2. Enhancement Factors for Prolate Spheroidal Geometry.- 3.3. Electrodynamic Effects.- 4. The Chemical Enhancement in SERS.- 4.1. Normal Raman Scattering.- 4.2. Resonance Raman Scattering.- 4.3. Herzberg-Teller Corrections.- 4.4. Surface-Enhanced Raman Spectroscopy: A Charge Transfer Theory.- 5. Overall Enhancement Equations for Surface Raman Scattering.- 5.1. Effect of Concentration in a Pure EM Surface Effect.- 5.2. Overall Enhancement Equation for SERS.- 5.3. Enhanced Scattering in a Surface-Enhanced Resonance Raman Process.- 6. Symmetry Considerations for SERS.- 6.1. Vibrational Selection Rules for SERS.- 6.2. Surface Selection Rules in SERS.- 7. Effects of Electrode Potential in SERS.- 7.1. Effect of Electrode Potential on SERS Intensities.- 7.1.1. Charge Transfer Resonance Dependence on Potential and Excitation Frequency.- 7.1.2. Electric Field Effects.- 7.2. SERS Intensities as a Function of Potential in the Presence of an Electrode Reaction.- 8. Application of SERS to Chemical Systems.- 8.1. Neutral Nitrogen-Containing Molecules on Ag and Cu Electrodes.- 8.2. Anions and the Effect of Supporting Electrolyte at Ag Electrodes.- 8.3. Cationic Species at Ag Electrodes.- 8.4. Hydrocarbons at Ag Films and Au Electrodes.- 8.5. SERS under Nonstandard Conditions and in Nonaqueous Media.- References.- 7. ESR Spectroscopy of Electrode Processes.- 1. Introduction.- 1.1. External Generation Methods.- 1.2. Internal Generation Methods.- 2. Theory.- 2.1. Introductory Remarks.- 2.2. The g-Value.- 2.3. Hyperfine Splitting.- 2.4. Linewidths.- 2.5. The ESR Spectrometer.- 3. Practice.- 3.1. The Allendoerfer Cell.- 3.2. The Compton-Coles Cell.- 3.3. The Compton-Waller Cell.- 3.4 Some Practical Hints.- 4. Applications.- 4.1. Radical Identification.- 4.2. Spin Trapping.- 4.3. The Kinetics and Mechanisms of Electrode Reactions.- 4.4. Dynamic Processes and ESR Lineshapes.- 4.5. Adsorbed Radicals.- References.- 8. Mössbauer Spectroscopy.- 1. Introduction.- 2. Theoretical Aspects.- 2.1. Recoil Energy, Resonance, and Doppler Effect.- 2.2. Phonons, Mössbauer Effect, and Recoilless Fraction.- 2.3. Electric Hyperfine Interactions.- 2.3.1. Isomer Shift.- 2.3.2. Quadrupole Splitting.- 2.4. Magnetic Hyperfine Interaction.- 3. Experimental Aspects.- 3.1. Instrumentation and Modes of Operation.- 3.2. Sources, Data Acquisition, and Data Analysis.- 3.3. In Situ Mössbauer Spectroscopy.- 3.4. Quasi In Situ Mössbauer Spectroscopy.- 3.4.1. Quasi In Situ Conversion Electron Mössbauer Spectroscopy.- 3.4.2. Low-Temperature Quenching.- 3.5. Limitations of the Technique.- 4. Model Systems.- 4.1. Electrochemical Properties of Iron and Its Oxides.- 4.1.1. The Iron Oxyhydroxide System.- 4.1.2. The Passive Film of Iron.- 4.2. Mixed Ni-Fe Oxyhydroxides as Electrocatalysts for Oxygen Evolution.- 4.3. Prussian Blue.- 4.4. Transition Metal Macrocycles as Catalysts for the Electrochemical Reduction of Dioxygen.- 4.5. Tin.- 4.6. In Situ Emission Mössbauer.- References.