The Kinetics of Hydrogen Absorption into Iron during Cathodic Hydrogen Evolution

Kim, C. D.; Wilde, B. E.

doi:10.1149/1.2407967

Cited by 72 publications

(46 citation statements)

References 11 publications

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“…Ix 10 -7 5x i0 -6 7x 10 -u k"(molcm -*) 2 x 10 -6 2 x 10 -7 8 x I0 -3 I x 10 -5] in the Appendix) is easily solved for each of the cases, and these a values are given in Table I. Figure 3 shows the i= vs. ~ plots, which are all linear as confirmed by various statistical tests.…”

Section: Resultsmentioning

confidence: 79%

“…5, which shows that the hydrogen surface coverages are quite small in all of the cases, i.e., O~ < 0.15. Although only a few experimental determinations of Os exist in the literature, values for comparison with those in this paper for the 0.1N H2SO4 solutions have yielded simL lar 0~ values, i.e., in the range of 0.01 to 0.1(10,21). More (direct) experimental measurements of 0~, however, are needed for checking the model.As shown above, this model is able to determine the transfer coefficient a, as per Eq.…”

mentioning

confidence: 69%

“…In order for these latter two reactions to take place, an intermediate adsorption-absorption step is involved (10,11). A quantitative derivation of the relationships between hydrogen surface coverage, rate constants, transfer coefficient, etc., and hydrogen charging current, overpotential and permeation flux, is presented below with the following conditions or assumptions:…”

Section: Theoreticalmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of Hydrogen Evolution and Entry into Metals for the Discharge‐Recombination Process

Iyer¹,

Pickering²,

Zamanzadeh³

1989

J. Electrochem. Soc.

150

130

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A mechanistic model has been developed which for the first time considers the effect of hydrogen entry into a metal on the kinetics of the hydrogen evolution reaction (h.e.r.). The model enables computation of (i) the hydrogen surface coverage and surface concentration; (ii) the hydrogen adsorption, absorption, discharge and recombination rate constants; and (iii) the h.e.r, coverage-dependent transfer coefficient, ~, and the exchange current density io, from a knowledge of the steady-state hydrogen permeation current, cathodic charging current, hydrogen overvoltage, and hydrogen diffusivity. The model predicts a linear relationship between the permeation flux and the square root of the hydrogen recombination flux, and provides an analytical method to determine the cathodic potential range for operation of a coupled dischargerecombination mechanism of the h.e.r. With modifications the model can treat permeation data for which (i) the mechanics of the discharge step involve a (proposed) selvedge reaction, and (ii) surface hydrogen coverages are relatively high as in the presence of poisons (e.g., H2S or As2OD. Some of the existing literature data for hydrogen permeation in iron and nickel in acid and alkaline solutions are successfully analyzed.Hydrogen is one of the most damaging species in metals, causing hydrogen assisted cracking, blisters, and similar phenomena. Hydrogen entry into metals from aqueous solutions has been studied extensively by hydrogen permeation experiments of thin samples using the DevanathanStachurski cell (1-7). Some studies carried out on iron in acid and alkaline solutions (2, 4, 6) reveal a coupled discharge-recombination mechanism for the hydrogen evolution reaction (h.e.r.) with diffusion of absorbed hydrogen into the metal being rate controlling for the permeation process. The models based on this mechanism predict a square-root relationship between the hydrogen charging current and the steady-state hydrogen permeation flux or current (2). In all of these models, it has been assumed that the hydrogen permeation flux is negligible. It has also been assumed that the hydrogen coverage (Os) is quite low, although the coverage itself is unknown. However, especially when poisons such as H2S or As~O3 are present in the solution, both the permeation current and the hydrogen coverage can be appreciable (8,9). If the steady-state permeation current (i~) is proportional to the square root of the charging current (and the Tafel slope is -120 mV decade -~ and d~l/d log i~ is -240 mV decade -~ where ~1 is the overpotential for the h.e.r.), the h.e.r, is generally considered to follow a coupled diseharge-reeombinati0n mechanism. Apart from these considerations which have not produced operative models yielding the relevant parameters, e.g., 0s, the current models also do not explain the mechanics of the intermediate reaction between adsorption and absorption of hydrogen in metals, which is probably correctly assumed in many eases, but perhaps not in all, to be in equilibrium at the cathode surface.T...

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Section: Resultsmentioning

confidence: 79%

mentioning

confidence: 69%

Section: Theoreticalmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of Hydrogen Evolution and Entry into Metals for the Discharge‐Recombination Process

Iyer¹,

Pickering²,

Zamanzadeh³

1989

J. Electrochem. Soc.

150

130

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“…The analysis of the results makes use of models that have been extensively tested in the literature. 1,8,9,17,21,30,[40][41][42][43][44][45][46] Model Consider a coupled (Volmer) discharge-(Tafel) recombination mechanism for the HER, taking place on the left side of the membrane shown in Fig. 1, i.e.…”

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confidence: 99%

The Effect of Iodide Ions on the Kinetics of Hydrogen Absorption by Iron

Elhamid

Ateya

Pickering

2000

J. Electrochem. Soc.

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The presence of some additives in the environment affects the kinetics of the hydrogen evolution reaction (HER) on the surface (see Eq. 1 and 2) and, consequently, the hydrogen absorption reaction (HAR) within metals (Eq. 3). While some compounds inhibit both reactions, for example, benzonitrile, benzotriazole, and pyrroles, 1-7 others inhibit the HER while promoting the HAR, 8-28 e.g., iodide ions, thiourea, and aminotriazole. 1,2,8,15,[18][19][20][21] The mechanism of action of these additives is attracting considerable attention. [1][2][3] Inhibitors of both the HER and HAR are compounds which adsorb preferentially on the metal surface and hence decrease the hydrogen surface coverage, which in turn decreases the rate of both the HER and HAR. 1,2,7,33,34 By similar argument, others 8,9,11,35 attributed the effect of promoters of the HAR (Eq. 3) to inhibition of the recombination reaction (Eq. 2). This leads to a decrease in the rate of the HER (Eq. 2) but to an increase in the hydrogen surface coverage and hence to an increase in the hydrogen absorption. It has also been suggested that the adsorbed species, including iodide in acid sulfate solution, weaken the metal hydrogen bond 1,10,15,17 and hence facilitate the entry of hydrogen into the metal. Another group of authors attributed the accelerating affect of these additives on the HAR to an electronic interaction between the adsorbed hydrogen atoms and the adsorbed additive. 24,26,36 While additives with electron donating nature, such as iodide, 37 are reasoned to accelerate hydrogen absorption, those with electron withdrawing nature have the opposite effect. 24,26,36 Recently, Qian et al. 38,39 investigated the effect of arsenic oxide and hydrogen sulfide in promoting hydrogen absorption into iron and steel in alkaline solutions. Their results revealed that arsenic oxide enhances hydrogen absorption through its reduction to arsenic hydride (AsH 3 ). These authors concluded that AsH 3 is desorbed from the metal surface, thereby increasing the number of adsorption sites for hydrogen. Thus, the hydrogen surface coverage and, consequently, the hydrogen absorption rate are increased 38 as reported earlier. 8 In the case of hydrogen sulfide in alkaline solution, they concluded that HS Ϫ adsorbs on the surface, thereby, decreasing both the hydrogen surface coverage and the hydrogen desorption rate, although enhancing hydrogen absorption. 39 In a prior study of the Fe/H 2 S-acid system, Iyer et al. 40 concluded that H 2 S caused an increase in the hydrogen surface coverage and, in turn, accounted for the increase in the hydrogen absorption rate.The aim of the present study is to analyze the effects of iodide ions on the kinetics of both the HER and HAR on iron in a more in-depth manner than in the past. Of particular importance is the effect of iodide ions on the hydrogen coverage of the iron surface and the rate constant of the hydrogen absorption step which affects the rate of hydrogen permeation within iron. The analysis of the results makes use of models that ha...

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“…The scope of the obtained data shows that guanidine does not change the character of HER limiting stage, which is discharge of H 3 O + , on iron in acidic aqueous chloride solutions whereas H ads concentration expressed through the surface coverage (H H ) is within the limits of H H 6 0.1 according to [12][13][14].…”

Section: Aqueous Solutionsmentioning

confidence: 91%

Influence of guanidine on kinetics of hydrogen evolution reaction on iron and its diffusion through steel membrane in acidic chloride media

Вигдорович

Цыганкова

Balybin

2011

Journal of Electroanalytical Chemistry

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The Kinetics of Hydrogen Absorption into Iron during Cathodic Hydrogen Evolution

Cited by 72 publications

References 11 publications

Analysis of Hydrogen Evolution and Entry into Metals for the Discharge‐Recombination Process

Analysis of Hydrogen Evolution and Entry into Metals for the Discharge‐Recombination Process

The Effect of Iodide Ions on the Kinetics of Hydrogen Absorption by Iron

Influence of guanidine on kinetics of hydrogen evolution reaction on iron and its diffusion through steel membrane in acidic chloride media

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