Response to comments on: The phase-shift method for determining Langmuir adsorption isotherms of over-potentially deposited hydrogen for the cathodic H2 evolution reaction at poly-Re/aqueous electrolyte interfaces[Hydrogen Energy 30 (2005) 485–499]

Chun, Jang H.; Jeon, Sang Koo; Kim, Nam Y.; Chun, Jin Y.

doi:10.1016/j.ijhydene.2005.02.007

Cited by 10 publications

(4 citation statements)

References 10 publications

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“…However, the objections to the phase-shift method − do not fulfill these criteria. These objections are substantially attributed to confusion and misunderstanding of the phase-shift method itself. ,,, It should especially be noted that all of the objections to the phase-shift method , can be attributed to confusion and misunderstanding about the applicability of related equations for intermediate frequencies and a unique feature of the Faradaic resistances for the recombination steps. ,, …”

Section: Introductionmentioning

confidence: 99%

Determination of the Adsorption Isotherms of Hydrogen and Deuterium Isotopes on a Pt−Ir Alloy in LiOH Solutions Using the Phase-Shift Method and Correlation Constants

2010

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The phase-shift method and correlation constants, which are unique electrochemical impedance spectroscopy techniques for studying the linear relationship between the phase shift (90° ≥ −φ ≥ 0°) versus electric potential (E) behavior for the optimum intermediate frequency and the fractional surface coverage (0 ≤ θ ≤ 1) vs E behavior, are proposed and verified to determine the Frumkin, Langmuir, and Temkin adsorption isotherms and related electrode kinetic and thermodynamic parameters. On a Pt−Ir alloy (90:10 mass ratio) in 0.1 M LiOH (H2O) and 0.1 M LiOH (D2O) solutions, the Frumkin and Temkin adsorption isotherms (θ vs E), equilibrium constants (K), interaction parameters (g), standard Gibbs energies (ΔG θ °) of hydrogen (H) and deuterium (D) adsorption, and rates of change (r) of ΔG θ ° of H and D with θ have been determined and are compared using the phase-shift method and correlation constants. The value of K decreases in going from H2O to D2O. The values of K for both H and D increase with increasing E and θ. Over the θ range (i.e., 1 ≥ θ ≥ 0), the value of K for H is 3.7 to 4.1 times greater than that for D. For 0.2 < θ < 0.8, a lateral attractive (g < 0) or repulsive (g > 0) interaction between the adsorbed H or D species appears. The duality of the lateral attractive and repulsive interactions is a unique feature of the adsorbed H and D species on Pt, Ir, and Pt−Ir alloys in acidic and alkaline H2O and D2O solutions.

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Section: Introductionmentioning

confidence: 99%

Determination of the Adsorption Isotherms of Hydrogen and Deuterium Isotopes on a Pt−Ir Alloy in LiOH Solutions Using the Phase-Shift Method and Correlation Constants

2010

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“…The arguments are substantially attributed to the misunderstanding and confusion on the newly defined equivalent circuit for the phase-shift method, the simplified equivalent circuit for the optimum intermediate frequency response, the linear relationship between −φ vs E and θ vs E for the optimum intermediate frequency, etc. These rebuttals are clearly explained, stated, and summarized in the responses. , The whole procedure of the phase-shift method and correlation constants for determining the adsorption isotherms of hydrogen and hydroxide and related electrode kinetic and thermodynamic parameters is described elsewhere …”

Section: Introductionmentioning

confidence: 99%

Determination of Adsorption Isotherms of Hydrogen on Titanium in Sulfuric Acid Solution Using the Phase-Shift Method and Correlation Constants

Chun

2009

J. Chem. Eng. Data

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The phase-shift method and correlation constants, i.e., the unique electrochemical impedance spectroscopy (EIS) techniques for studying the linear relationship between the behavior (-φ vs E) of the phase shift (90°g -φ g 0°) for the optimum intermediate frequency and that (θ vs E) of the fractional surface coverage (0 e θ e 1), have been proposed and verified to determine the Langmuir, Frumkin, and Temkin adsorption isotherms of H and related electrode kinetic and thermodynamic parameters on noble metals (alloys) in aqueous solutions. On Ti in 0.5 M H 2 SO 4 aqueous solution, the Frumkin and Temkin adsorption isotherms (θ vs E), equilibrium constants (K ) 8.3 • 10 -12 exp(-6.6θ) mol -1 for the Frumkin, and K ) 8.3 • 10 -11 exp(-11.2θ) mol -1 for the Temkin adsorption isotherm), interaction parameters (g ) 6.6 for the Frumkin and g ) 11.2 for the Temkin adsorption isotherm), rates of change of the standard free energy (r ) 16.4 kJ • mol -1 for g ) 6.6 and r ) 27.8 kJ • mol -1 for g ) 11.2) of H with θ, and standard free energies [(63.2 e ∆G θ 0 e 79.6) kJ • mol -1 for K ) 8.3 • 10 -12 exp(-6.6θ) mol -1 and 0 e θ e 1 and (63.1 < ∆G θ 0 < 79.6) kJ • mol -1 for K ) 8.3 • 10 -11 exp(-11.2θ) mol -1 and 0.2 < θ < 0.8] of H are determined using the phaseshift method and correlation constants. At 0.2 < θ < 0.8, the Temkin adsorption isotherm correlating with the Frumkin adsorption isotherm, and vice versa, is readily determined using the correlation constants. The two different adsorption isotherms appear to fit the same data regardless of their adsorption conditions. The phase-shift method and correlation constants are probably the most accurate, useful, and effective ways to determine the adsorption isotherms of H and related electrode kinetic and thermodynamic parameters on highly corrosion-resistant metals in aqueous solutions.

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“…The validity and correctness of the phase-shift method should be discussed on the basis of simulations with a single equation for −φ versus θ as functions of E and frequency ( f ) or relevant experimental results which are obtained using other conventional methods. However, the single equation for −φ versus θ as functions of E and f has never been derived or discussed on the basis of relevant experimental results. − The simulations of the phase-shift method without this single equation, that is, −φ versus θ, are basically meaningless or in vain. − ,− It should be noted that this problem has been experimentally and consistently solved using the phase-shift method for determining adsorption isotherms.…”

Section: Introductionmentioning

confidence: 94%

“…However, the objections to the phase-shift method − do not fulfill these criteria. These objections are substantially attributed to confusion and misunderstanding about the phase-shift method itself. − ,, It should especially be noted that all of the objections to the phase-shift method , can be attributed to confusion and misunderstanding about the applicability of related equations for intermediate frequencies and a unique feature of the Faradaic resistances for the recombination steps. − , …”

Section: Introductionmentioning

confidence: 99%

Determination of the Adsorption Isotherms of Overpotentially Deposited Hydrogen on a Pt−Ir Alloy in H₂SO₄ Aqueous Solution Using the Phase-Shift Method and Correlation Constants

2011

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The phase-shift method and correlation constants, which are unique electrochemical impedance spectroscopy techniques for studying the linear relationship between the phase shift (90° ≥ −φ ≥ 0°) versus electric potential (E) behavior for the optimum intermediate frequency and the fractional surface coverage (0 ≤ θ ≤ 1) vs E behavior, are proposed and verified to determine the Frumkin, Langmuir, and Temkin adsorption isotherms and related electrode kinetic and thermodynamic parameters. On a Pt−Ir [90:10 % (by weight)] alloy in 0.5 M H2SO4 aqueous solution, the Frumkin and Temkin adsorption isotherms (θ vs E), equilibrium constants [K = 3.3 · 10−5 exp(2.5θ) mol−1 for the Frumkin and K = 3.3 · 10−4 exp(−2.1θ) mol−1 for the Temkin adsorption isotherm], interaction parameters (g = −2.5 for the Frumkin and g = 2.1 for the Temkin adsorption isotherm), standard Gibbs energies of adsorption of overpotentially deposited (OPD) H [(25.6 ≥ ΔG θ 0 ≥ 19.4) kJ·mol−1 for K = 3.3 · 10−5 exp(2.5θ) mol−1 and 0 ≤ θ ≤ 1 and (20.9 < ΔG θ 0 < 24.0) kJ·mol−1 for K = 3.3 · 10−4 exp(−2.1θ) mol−1 and 0.2 < θ < 0.8], and rates of change of ΔG θ 0 of OPD H with θ (r = −6.2 kJ·mol−1 for g = −2.5 and r = 5.2 kJ·mol−1 for g = 2.1) have been determined and are compared using the phase-shift method and correlation constants. For 0.2 < θ < 0.8, a lateral attractive (g < 0) or repulsive (g > 0) interaction between the adsorbed OPD H species appears. On Pt, Ir, and Pt−Ir alloys in 0.5 M H2SO4 aqueous solution, the values of K for the Frumkin adsorption isotherms of OPD H decrease with increasing mass ratio of Ir. Negative values of g for the Frumkin adsorption isotherms of OPD H on the Pt, Ir, and Pt−Ir alloys in acidic and alkaline H2O and D2O solutions are experimentally and consistently determined. The duality of the lateral attractive and repulsive interactions is a unique feature of the adsorbed OPD H species on the Pt, Ir, and Pt−Ir alloys in acidic and alkaline H2O and D2O solutions.

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Response to comments on: The phase-shift method for determining Langmuir adsorption isotherms of over-potentially deposited hydrogen for the cathodic H2 evolution reaction at poly-Re/aqueous electrolyte interfaces[Hydrogen Energy 30 (2005) 485–499]

Cited by 10 publications

References 10 publications

Determination of the Adsorption Isotherms of Hydrogen and Deuterium Isotopes on a Pt−Ir Alloy in LiOH Solutions Using the Phase-Shift Method and Correlation Constants

Determination of the Adsorption Isotherms of Hydrogen and Deuterium Isotopes on a Pt−Ir Alloy in LiOH Solutions Using the Phase-Shift Method and Correlation Constants

Determination of Adsorption Isotherms of Hydrogen on Titanium in Sulfuric Acid Solution Using the Phase-Shift Method and Correlation Constants

Determination of the Adsorption Isotherms of Overpotentially Deposited Hydrogen on a Pt−Ir Alloy in H₂SO₄ Aqueous Solution Using the Phase-Shift Method and Correlation Constants

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Response to comments on: The phase-shift method for determining Langmuir adsorption isotherms of over-potentially deposited hydrogen for the cathodic H2 evolution reaction at poly-Re/aqueous electrolyte interfaces[Hydrogen Energy 30 (2005) 485–499]

Cited by 10 publications

References 10 publications

Determination of the Adsorption Isotherms of Hydrogen and Deuterium Isotopes on a Pt−Ir Alloy in LiOH Solutions Using the Phase-Shift Method and Correlation Constants

Determination of the Adsorption Isotherms of Hydrogen and Deuterium Isotopes on a Pt−Ir Alloy in LiOH Solutions Using the Phase-Shift Method and Correlation Constants

Determination of Adsorption Isotherms of Hydrogen on Titanium in Sulfuric Acid Solution Using the Phase-Shift Method and Correlation Constants

Determination of the Adsorption Isotherms of Overpotentially Deposited Hydrogen on a Pt−Ir Alloy in H2SO4 Aqueous Solution Using the Phase-Shift Method and Correlation Constants

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Determination of the Adsorption Isotherms of Overpotentially Deposited Hydrogen on a Pt−Ir Alloy in H₂SO₄ Aqueous Solution Using the Phase-Shift Method and Correlation Constants