Description
The systematic study of the adsorption of organic compounds on electrodes began with the comprehensive survey of adsorption on mercury carried out by Gouy in the first decade of this century. His studies with the capillary electrometer are still useful but do not lend themselves to detailed quantitative analysis. A more de tailed study of a few systems by Frumkin in his thesis (1919) led him to propose a quantitative phenomenological theory of organic adsorption (1925, 1926) at almost the same time as Stern proposed the model of the electrical double layer which remains the picture accepted in general terms today. The attempt at a molecular model made by Butler (1929) should be more satisfying but up to the pres ent the formidable difficulties of a molecular theory of interfacial phenomena have prevented the full interpretation of experimental results along these lines. In his work with Proskurnin (1935), Frumkin is also respon sible for the major experimental advance in the demonstration that reliable measurements of the capacity of an electrode-solution interface can be obtained provided that the work is carried out under conditions of scrupulous cleanliness. Even so, preCise mea surements of double layer capacities were not obtained until Grahame (1941) showed how convenient and reliable the dropping mercury electrode was the for these studies. This method and the hanging drop electrode remain the preferred methods for study of adsorp tion on mercury. Solid electrodes present a more difficult problem. I. Absorption of Organic Compounds on Liquid Electrodes.- 1. Methods for Studying Adsorption of Organic Substances on Liquid Electrodes.- 1. Methods of Measuring Interfacial Tension.- 2. Methods of Measuring the Capacity of the Double Layer.- 3. Thermodynamic Methods for Calculating Adsorption of Organic Substances from the Results of Measurements of the Interfacial Tension and Double Layer Capacity.- References.- 2. Experiment Data on Adsorption of Organic Substances on Liquid Electrodes.- 1. Electrocapillary Measurements on Mercury in Presence of Organic Compounds.- 2. Influence of Adsorption of Organic Substances on the Capacity of the Mercury Electrodes.- 3. Relation between the Frequency Dependence of the Differential Capacity and the Kinetics of Adsorption of Organic Compounds.- 4. Adsorption of Organic Substances on Other Liquid Electrodes.- References.- 3. Quantitative Theory of the Influence of an Electric Field on Adsorption of Organic Substances at a Mercury Electrode.- 1. Selection of the Electrical Variable.- 2. Certain General Relationships, Independent of the Particular Form of the Adsorption Isotherm.- a. Dependence of the Energy of Adsorption on the Electrode Potential.- b. Characteristics of Equilibrium C vs ? Curves with Considerable Adsorption of Organic Substances.- 3. Selection and Verification of the Adsorption Isotherm.- 4. Properties of Differential Capacity Curves Determined in Presence of Organic Substances the Adsorption of which Conforms to the Frumkin Isotherm.- a. Properties of Equilibrium C vs ? Curves.- b. Properties of Nonequilibrium C vs ? Curves.- c. Properties of C vs ? Curves Under Conditions of Two-Dimensional Condensation of the Organic Substance.- 5. Interpretation of the Complete Differential Capacity Curves Determined in Presence of Aliphatic Compounds.- 6. Certain Causes of the Deviation of Real Systems from the Model of Two Parallel Condensers.- 7. Interpretation of the Adsorption Behavior of Aromatic and Heterocyclic Compounds.- References.- 4. Nonthermodynamic Methods for Calculating Adsorption of Organic Substances on Electrodes.- 1. The Surface Pressure Method.- 2. Methods for Determination of the Attraction Constant at Various Electrode Potentials.- a. Determination of the Attraction Constant at the Potential Adsorption from the Shape of the Adsorption Isotherm.- b. Determination of the Attraction Constant at the Peak Potentials from Equilibrium C vs Curves.- c. Determination of the Attraction Constant at the Peak Potentials from Nonequilibrium C vs Curves.- 3. Methods for Determination of the Adsorption Potential Difference, the Maximum Amount of Organic Substance Adsorbed, and the Free Energy of Adsorption.- 4. Method Based on the Dependence of the Differential Capacity on the Concentration of the Organic Substance.- 5. Devanathan’s Method.- References.- II. Adsorption of Organic Compounds on Solid Electrodes.- 5. Methods for Studying Adsorption of Organic Substances on Solid Electrodes.- 1. Methods for Determination of Adsorption from Changes in Interfacial Tension.- 2. Special Features of Methods for Measuring DoubleLayer Capacity on Solid Metals.- 3. Study of Adsorption With the Aid of Electrochemical Oxidation or Reduction of Adsorbed Substances.- a. Method of Electrochemical Oxidation (or Reduction) in the Adsorbed Layer.- b. Potentiodynamic and Potentiostatic Pulse Methods.- 4. Methods for Studying Adsorption of Organic Substances Based on Adsorptional Displacement.- 5. Study of Adsorption of Organic Substances with the Aid of Radioactive Tracers.- 6. Determination of Adsorption from the Weight Increase of the Adsorbent or from the Decrease of the Adsorbate Contents in Solution.- 7. Study of Adsorption with the Aid of the Electrode Photoelectric Effect.- 8. Certain Other Methods for Studying Adsorption on Solid Electrodes.- References.- 6. Adsorption of Organic Substances on Metals of High Hydrogen Overpotential.- 1. Experimental Data on Adsorption of Organic Substances on Metals of High Hydrogen Overpotential.- 2. Data on Adsorption of Organic Substances on Silver and Copper.- 3. Influence of the Nature of the Metal on Adsorption of Organic Substances.- a. Role of the State of Aggregation.- b. Surface Heterogeneity.- c. Competitive Adsorption of Organic Molecules and Water.- d. Role of Adsorbed Gases and Ions.- References.- 7. Adsorption of Organic Compounds on Metals of the Iron Group.- 1. Dependence of Adsorption on the Potential and Position of the Point of Zero Charge.- 2. Joint Adsorption of Anions and Cations.- 3. Dependence of the Adsorption of Organic Substances on Concentration.- 4. Influence of Mechanical and Thermal Treatment on the Adsorption Properties of Electrodes.- 5. Dependence of Adsorption on Structure.- 6. Influence of Adsorbed Reaction Products and Intermediates on Adsorption of Organic Substances.- 7. Chemical Changes of Adsorbed Substances on Electrode Surfaces.- 8. Influence of Dissolution and Electrodeposition of Metals on the Concentration of Adsorbed Substances.- a. Dissolution of Metals.- b. Electrodeposition of Metals.- 9. Influence of Adsorption of Organic Substances on Metal Corrosion.- References.- 8. Mechanism of Adsorption of Organic Compounds on Electrodes of Metals of the Platinum Group.- 1. Adsorption of Methanol on Platinum Metals.- 2. Identification of the Adsorption Products of Saturated Alcohols, Ethylene Glycol, Aldehydes, and Acids.- 3. Adsorption of Carbon Monoxide and Carbon Dioxide.- 4. Behavior of Platinum-Metal Electrodes in Solutions of Hydrocarbons.- 5. Influence of Adsorption of Inorganic Ions on Adsorption of Organic Substances.- 6. Joint Adsorption of Hydrogen and Organic Substances.- 7. Evolution of Molecular Hydrogen during Contact of Organic Substances with Platinum Catalysts.- References.- 9. Thermodynamics of Surface Phenomena on Electrodes Adsorbing Hydrogen and Oxygen.- 1. Dependence of the Potential of a Platinum Electrode on the Solution pH under Isoelectric Conditions.- 2. Dependence of the Potential of a Platinum Electrode on the Composition of the Solution under Isoelectric Conditions.- 3. Influence of Adsorption of Hydrogen and Oxygen on Adsorption of Organic Compounds.- 4. Potentials of Zero Charge of the Platinum Metals and Their Dependence on the Solution pH.- References.- 10. Relationships in Adsorption of Organic Compounds on Metals of the Platinum Group.- 1. Dependence of Adsorption of Organic Compounds on the Electrode Potential and Solution pH.- 2. Dependence of Adsorption of Organic Compounds on Concentration. Adsorption Isotherms.- 3. Adsorption Kinetics of Organic Compounds.- 4. Relation between Adsorption and Kinetics of Anodic Oxidation of Organic Compounds on Platinum Electrodes.- 5. Influence of the Preparation Conditions and Nature of the Electrode on Adsorption of Organic Compounds.- 6. Adsorption of Organic Substances at High Anodic Potentials.- References.
