Electrified interphase

The ILs interact with surfaces and electrodes [23-25], and many more studies have been done that what we can cite. As one example, in situ Fourier-transform infrared reflection absorption spectroscopy (FT-IRAS) has been utilized to study the molecular structure of the electrified interphase between a l-ethyl-3-methylimidazolium tetrafluoroborate [C2Qlm][BF4] liquid and gold substrates [26]. Similar results have been obtained by surface-enhanced Raman scattering (SERS) for [C4Cilm][PFg] adsorbed on silver [24,27] and quartz [28]. 

R. Parsons, Equilibrium Properties of Electrified Interphases, in Modem Aspects cf Electrochemistry, J. O M. Bockris and B. Conway, eds., Vol. 1, Butterworths London (1954). 

The clearest introduction to the electrochemical potential (hat is given by its creator, in Chap. 8ofIv. A. Guggenheim, Thermodynamics, North-1 lollaiul, Amsterdam, 1967. [ lie issue of electric potentials near interfaces is discussed in detail in K. Faisons, Fquilihrium properties of electrified interphases. Modern Aspects Etectrochem. 1 103 (1954). 

Ref. [i] Parsons R (1954) Equilibrium properties of electrified interphases. In Bockris JO M, Conway BE (eds) Modern aspects of electrochemistry. Academic Press, New York... 

Interphases containing free charged components, which are usually accumulated or depleted in the surface regions, are called electrified interphases. When charged components are present in the two phases, electroneu-... 

Refs. [i] Frumkin AN (1979) Potentsialy nulevogo zaryada (in Russian) (Potentials of zero charge). Nauka, Moscow [ii] Parsons R (1954) Equilibrium properties of electrified interphases. In Bockris JO M (ed) Modern aspects of electrochemistry, vol. 1. Buttersworth, London, p 103 [in] Trasatti S (1975) JElectroanal Chem 66 155 [iv] Hillier AC, Kim S, Bard AJ (1996) J Phys Chem 100 18808 [v] Thomas RC, TangyunyongP, Houston JE, Michalske TA, Crooks RM (1994) J Phys Chem 98 4493... 

For sodium dodecanesulfonate, a classical IPR for positively charged analytes, the potential determining ion is dodecanesulfonate, while the counter ion is the sodium cation. The electrified interphase will carry a barely negative charge since... 

This means that a heterogeneous catalytic system where an electrified interphase is formed cannot be unambiguously treated ignoring the electrochemical parameters. 

The Role of Electrosorption (Adsorption Processes). - The adsorbed species play a central role in catalytic and electrocatalytic transformations. The knowledge of the adsorption behavior of the various species present in a given system and the clarification of their competitive adsorption processes present a fundamental requirement for the interpretation of the kinetic data and for the elaboration of appropriate synthetic methods. In the case of electrified interphases, these requirements cannot be met if we neglect the monitoring of the electrode potential. 

The state of any electrified interphase depends on the potential. It is well known from the electrochemistry that the adsorption, electrosorption processes of ions and neutral molecules are strongly influenced by the potential of the electrode. 

In the historical development of the concept of electrified interphase, the modeling preceded the strict thermodynamic description and thus for a long period, only the double-layer model served as a unique... 

During the first haF of the last century, both the theoretical and experimental work in coimection with electrified interphases were mainly centered around the mercury-water system. 

The rigoroiis analysis of the effect of temperature variations on interfacial properties is a key tool to provide new and valuable information on the structure and reactivity of the metal solution interphase. The entropy of the components that form the interphase is a unique probe of their stmctural properties. Therefore, this experimental data is particularly useful for the validation of molecular models of electrified interphases. In addition, the use of fast temperature perturbations is especially suitable for the selective characterization of different inter-facial components, based on their different response time towards the temperature change. In this way, the entropic properties of doublelayer phenomena and charge-transfer adsorption processes can be evaluated separately. It will be shown in this chapter that the combina-... 

Electrochemical impedance spectroscopy is extensively employed for the investigation of SAMs because the broad range of frequencies covered by this technique (usually from 10 to 10 Hz) may allow processes with different relaxation times taking place within the electrified interphase to be detected and sorted out. Unfortunately, the various relaxation times often differ by less than 2 orders of magnitude, thus requiring a certain amount of arbitrariness and of physical intuition for their separation. In fact, it is well known that the same impedance spectrum can often be equally well fitted to different equivalent circuits, which are consequently ascribed to different relaxation processes. Impedance spectra are frequently reported on a Y /co versus Y"/co plot, where Y and Y" are the in-phase and quadrature components of the electrochemical admittance and co is the angular frequency. This plot is particularly suitable for representing a series RC network. Thus, a series connection of R and C yields... 

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