The Kinetics of the Adiabatic and Nonadiabatic Reactions at the Metal and Semiconductor Electrodes

The basic results of the correct quantum-mechanical calculqtions of the probability of the elementary act of adiabatic homogeneous reactions are summarized. The calculations are carried out for the model of the one-dimensional potential energy curves without using the perturbation theory. The adiabatic and nonadiabatic electrochemical reactions at the metal and semiconductor electrodes are considered. The physical picture of the process is discussed. The adiabatic electrochemical process is shown to be of the many-electron character. The expressions for the transition probability is derived for the metal and semiconductor electrodes. The redox reactions at the semiconductor are considered in the presence of the surface states

The Kinetics of the Adiabatic and Nonadiabatic Reactions at the Metal and Semiconductor Electrodes

The basic results of the correct quantum-mechanical calculqtions of the probability of the elementary act of adiabatic homogeneous reactions are summarized. The calculations are carried out for the model of the one-dimensional potential energy curves without using the perturbation theory. The adiabatic and nonadiabatic electrochemical reactions at the metal and semiconductor electrodes are considered. The physical picture of the process is discussed. The adiabatic electrochemical process is shown to be of the many-electron character. The expressions for the transition probability is derived for the metal and semiconductor electrodes. The redox reactions at the semiconductor are considered in the presence of the surface states

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

THE THEORY OF THE ELEMENTARY ACT OF THE PROTON TRANSFER IN POLAR MEDIA

The hydrogen evolution reactions at metals were studied during many years. At present there are two different approaches to the calculation of the probability of the elementary act of proton transfer from the molecule AHz in solution to the adsorbed state at the electrode. One of them treats the proton transfer as the process of gradual stretching of the chemical bond H-A due to the transitions of the proton to the excited vibrational states in the molecule AHz 1), or as the process of movement of the system on two-dimensional potential energy surface2). Possible quantum effects are taken into account by introducing tunnel corrections, describing Gamov tunneling near the top of the potential barrier. This approach ignores entirely the rearrangement of the solvent molecules in the course of the reaction. The second approach takes into account both the motion of the proton and the reorganization of other intramolecular degrees of freedom of the reactants and the solvent molecules3 •4). The transition probability of th