Spectroelectrochemistry

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 $$ frac{3} {2} $$ 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. Mossbauer Spectroscopy.- 1. Introduction.- 2. Theoretical Aspects.- 2.1. Recoil Energy, Resonance, and Doppler Effect.- 2.2. Phonons, Mossbauer 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 Mossbauer Spectroscopy.- 3.4. Quasi In Situ Mossbauer Spectroscopy.- 3.4.1. Quasi In Situ Conversion Electron Mossbauer 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 Mossbauer.- References.