THE TEMPERATURE COEFFICIENT OF THE POTENTIAL OF ZERO CHARGE OF Ag SINGLE CRYSTAL FACE ELECTRODES IN AQUEOUS ELECTROLYTE SOLUTION

Doubova,; Trasatti,

doi:10.5488/cmp.4.4.759

Cited by 4 publications

(3 citation statements)

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“…These studies are especially useful to improve our understanding of structural effects on the double layer properties, and can be used to test the validity of models of the metal solution interphase [1][2][3]. In this respect, apart from classical works with mercury elec trodes [4][5][6][7][8][9], several works have been performed with gold [10][11][12][13] and silver [14][15][16] single crystals.…”

Section: Introductionmentioning

confidence: 99%

Temperature effects on platinum single-crystal electrodes

2012

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This work reviews three different approaches for the study of temperature effects on the platinum single crystal | solution interphase. First, the method of analysis of temperature dependent voltammetric data with the help of a generalized isotherm is described and illustrated for the case of adsorbed hydrogen and OH species on Pt(111) in 0.1 M HClO 4 . This method of analysis allows a detailed evaluation of the thermo dynamic data of charge transfer adsorbed species, namely, the standard molar Gibbs energy, enthalpy and entropy of adsorption and the magnitude of the lateral interaction between adsorbed species. However, a number of assumptions are involved in the application of a generalized isotherm, namely, the assumption of a Langmuirian configurational term and an arbitrary separation of capacitive and faradaic processes. The sec ond approach described here overcomes these assumptions, since it employs Gibbs thermodynamic equa tions for interphaces to describe temperature effects on electrosorption processes including those in which charge transfer is allowed. This approach allows evaluation of the entropy of formation of the interphase, being defined as the difference in entropy of the components of the interphase when they are forming it and when they are in the bulk phases. This method of analysis is illustrated through the evaluation of the entropy of formation of the interphase for Pt(111) in 0.1 M HClO 4 . Finally, it is shown that temperature effects on interfacial processes can also be studied by means of the application of a fast temperature perturbation. This approach opens the possibility to separate the effect of temperature on the different components of the inter phase. The fast temperature perturbation is usually achieved with short laser pulses, and hence the method is called the laser induced temperature jump method. This approach is illustrated here for the case of Pt(111) in 1 mM HClO 4 + 0.1 M KClO 4 , and it is shown that the corresponding laser induced transients provide direct evidence on the reorientation of the interfacial water network.

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Section: Introductionmentioning

confidence: 99%

Temperature effects on platinum single-crystal electrodes

2012

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“…The dependence of the differential capacitance (DC) on the electrode potential and temperature are of particular interest, as they provide valuable information regarding the electrode−electrolyte interfacial behavior. Experiments have demonstrated that, close to the potential of zero charge (PZC), the DC for RTILs can exhibit a maximum − or a minimum, − depending upon the particular electrode material, the specific RTIL, and the temperature. − Experiments on systems having a relatively wide electrochemical window revealed complex camel-shaped DC for both RTILs and aqueous solutions of salts, consisting of a minimum near PZC flanked by two maxima, with decreasing wings of DC at larger positive or negative electrode potentials. In 2007, Kornyshev pointed out that the traditional Gouy−Chapman−Stern model cannot predict a maximum at PZC observed for dense ionic liquids and offered a mean-field theory (MFT) that takes into account constrains imposed by ion packing.…”

Section: Introductionmentioning

confidence: 99%

Molecular Insights into the Potential and Temperature Dependences of the Differential Capacitance of a Room-Temperature Ionic Liquid at Graphite Electrodes

2010

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Molecular dynamics simulation studies of the structure and the differential capacitance (DC) for the ionic liquid (IL) N-methyl-N-propylpyrrolidinium bis(trifluoromethane)sulfonyl imide ([pyr(13)][TFSI]) near a graphite electrode have been performed as a function temperature and electrode potential. The IL exhibits a multilayer structure that extends 20-30 Å from the electrode surface. The composition and ion orientation in the innermost layer were found to be strongly dependent on the electrode potential. While at potentials near the potential of zero charge (PZC), both cations and anions adjacent to the surface are oriented primarily perpendicular to the surface, the counterions in first layer orient increasingly parallel to the surface with increasing electrode potential. A minimum in DC observed around -1 V(RPZC) (potential relative to the PZC) corresponds to the point of highest density of perpendicularly aligned TFSI near the electrode. Maxima in the DC observed around +1.5 and -2.5 V(RPZC) are associated with the onset of "saturation", or crowding, of the interfacial layer. The asymmetry of DC versus electrode polarity is the result of strong interactions between the fluorine of TFSI and the surface, the relatively large footprint of TFSI compared to pyr(13), and the tendency of the propyl tails of pyr(13) to remain adsorbed on the surface even at high positive potentials. Finally, an observed decreased DC and the disappearance of the minimum in DC near the PZC with increasing temperature are likely due to the increasing importance of entropic/excluded volume effects (interfacial crowding) with increasing temperature.

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“…Experimentally measured DCs for RTIL-based electrolytes typically are either bell-shaped − with a maximum at low potential or camel-shaped − (or U-shaped) with a minimum at potentials close to the potential of zero charge (PZC) and two maxima at higher potentials, depending on the nature of the electrode and electrolyte, ion asymmetry and temperature. Kornyshev proposed a simple analytical model that explained the shape of DC based on steric exclusions between the ions near surface and based on the compressibility of the electrolyte near the surface, over screening and lattice saturation effects.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation Study of the Interfacial Structure and Differential Capacitance of Alkylimidazolium Bis(trifluoromethanesulfonyl)imide [C_nmim][TFSI] Ionic Liquids at Graphite Electrodes

et al. 2012

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The dependence on electrode potential of the interfacial structure and differential capacitance (DC) for 1alkyl-3-methyimidazolium bis(trifluoromethanesulfonyl)imide ([C n mim][TFSI], n = 2, 4, 6, and 8) ionic liquids (IL) near basal (flat) and prismatic edge face (rough) graphite electrodes was investigated here with atomistic simulations. Overall camel-shaped DCs were observed for both surfaces. The prismatic graphite generated systematically larger capacitances than the atomically flat basal face. Although on the flat electrodes the DC is almost constant at electrode potential bellow saturation (i.e., roughly within ±2 V), on the prismatic edge face the DC showed large amplitude changes between minima and maxima. This trend in DC was explained from the dependence versus potential of the structure and composition of the interfacial electrolyte layer; specifically, faster counterions accumulation and ion segregation in the interfacial layer are observed for atomically corrugated electrode surfaces as compared to the flat ones. Surprisingly, the increase of the charge-neutral alkyl tail length of the cation resulted only in a small reduction in DC, indicating ions ability to rearrange/reorient charge-caring groups such that it maximizes the counterions charge near the surface. This finding shows a promising route for optimization of ions structure to achieve the desired/optimal properties of electrolyte (e.g., low melting point and viscosity) without significant reduction of energy density storage capabilities.

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THE TEMPERATURE COEFFICIENT OF THE POTENTIAL OF ZERO CHARGE OF Ag SINGLE CRYSTAL FACE ELECTRODES IN AQUEOUS ELECTROLYTE SOLUTION

Cited by 4 publications

References 15 publications

Temperature effects on platinum single-crystal electrodes

Temperature effects on platinum single-crystal electrodes

Molecular Insights into the Potential and Temperature Dependences of the Differential Capacitance of a Room-Temperature Ionic Liquid at Graphite Electrodes

Molecular Dynamics Simulation Study of the Interfacial Structure and Differential Capacitance of Alkylimidazolium Bis(trifluoromethanesulfonyl)imide [C_nmim][TFSI] Ionic Liquids at Graphite Electrodes

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THE TEMPERATURE COEFFICIENT OF THE POTENTIAL OF ZERO CHARGE OF Ag SINGLE CRYSTAL FACE ELECTRODES IN AQUEOUS ELECTROLYTE SOLUTION

Cited by 4 publications

References 15 publications

Temperature effects on platinum single-crystal electrodes

Temperature effects on platinum single-crystal electrodes

Molecular Insights into the Potential and Temperature Dependences of the Differential Capacitance of a Room-Temperature Ionic Liquid at Graphite Electrodes

Molecular Dynamics Simulation Study of the Interfacial Structure and Differential Capacitance of Alkylimidazolium Bis(trifluoromethanesulfonyl)imide [Cnmim][TFSI] Ionic Liquids at Graphite Electrodes

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Molecular Dynamics Simulation Study of the Interfacial Structure and Differential Capacitance of Alkylimidazolium Bis(trifluoromethanesulfonyl)imide [C_nmim][TFSI] Ionic Liquids at Graphite Electrodes