The use of phosphate to generate H-atoms at pH 5–8 as determined by photocurrents: electrochemical properties of H-atoms

O'NeiIl, P.; Busi, F.; Concialini, V.; Tubertini, O.

doi:10.1016/0022-0728(90)87062-o

Cited by 9 publications

(6 citation statements)

References 7 publications

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“…A few studies have observed that phosphate ions H 2 PO 4 À may lead to unexpected electrochemical reactions on platinum, and it has been proposed in early nineteenth that phosphate may undergo an electrochemical deprotonation on platinum electrode [1][2][3]. To our knowledge, these works did not get an important feedback, even if an abnormal behaviour have commonly been remarked in phosphatecontaining solutions around the cathodic potential values where proton reduction occurs.…”

Section: Introductionmentioning

confidence: 93%

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Electrochemical deprotonation of phosphate on stainless steel

Silva

Basseguy

Bergel

2004

Electrochimica Acta

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Voltammetric experiments performed in phosphate buffer at constant pH 8.0 on platinum and stainless steel revealed clear reduction currents, which were correlated to the concentrations of phosphate. On the basis of the reactions proposed previously, a model was elaborated, assuming that both H 2 PO 4 À and HPO 4 2À underwent cathodic deprotonation, and including the acid-base equilibriums. A kinetic model was derived by analogy with the equations generally used for hydrogen evolution. Numerical fitting of the experimental data confirmed that the phosphate species may act as an efficient catalyst of hydrogen evolution via electrochemical deprotonation. This reaction may introduce an unexpected reversible pathway of hydrogen formation in the mechanisms of anaerobic corrosion. The possible new insights offered by the electrochemical deprotonation of phosphate in microbially influenced corrosion was finally discussed.

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Section: Introductionmentioning

confidence: 93%

“…O'Neil et al [2] and then Takehara et al [3] assumed that phosphate ions interact with an electron to give an adsorbed hydrogen atom H ads , which can further react with another phosphate ion:…”

Section: Equationsmentioning

confidence: 99%

Electrochemical deprotonation of phosphate on stainless steel

Silva

Basseguy

Bergel

2004

Electrochimica Acta

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“…They proposed that, after the electrochemical reduction of the undissociated acid in the presence of a supporting electrolyte, the conjugate base of the acid (B À ) reacted with water or with protons (H þ ) to re-establish the acidebase equilibrium in the solution. O'Neil et al [14] and Takehara et al [15] showed that hydrogenated phosphate species may undergo an electrochemical deprotonation on platinum electrodes and Da Silva et al [10] showed that this electrochemical deprotonation of phosphate was possible on stainless steel electrodes according to the following reaction mechanism:…”

Section: Introductionmentioning

confidence: 99%

Hydrogen production by electrolysis of a phosphate solution on a stainless steel cathode

Munoz

Bergel

Féron

et al. 2010

International Journal of Hydrogen Energy

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“…(3) and (4)) and proposed some diagnostic criteria for discriminating between the two mechanisms using curves of current vs. pH at a constant potential or of potential vs. pH at a constant current. O'Neil et al [41] and Takehara et al [42] showed that hydrogenated phosphate species may undergo an electrochemical deprotonation on platinum electrodes. As mentioned above, we previously demonstrated the occurrence of this electrochemical deprotonation of phosphate on stainless steel and proposed a reversible reaction mechanism [29].…”

Section: Weak Acid Reduction Mechanismsmentioning

confidence: 99%

“…The electrochemical reduction of phosphates and other weak acids on various electrodes has been the subject of several investigations [29,[34][35][36][37][38][39][40][41][42][43][44][45]. The most widely accepted mechanism for the reduction of weak acids is of the CE (chemical-electrochemical) type, where the dissociation of the acid takes place before the electrochemical reduction of free protons [32][33][34]:…”

Section: Weak Acid Reduction Mechanismsmentioning

confidence: 99%

Role of the reversible electrochemical deprotonation of phosphate species in anaerobic biocorrosion of steels

2007

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Sulphate reducing bacteria are known to play a major role in anaerobic microbiological influenced corrosion of steels, but mechanisms behind their influence are still source of debates as certain phenomena remain unexplained. Some experiments have shown that hydrogen consumption by SRB or hydrogenase increased the corrosion rate of mild steel. This was observed only in the presence of phosphate species. Here the cathodic behaviour of phosphate species on steel was studied to elucidate the role of phosphate in anaerobic corrosion of steel. Results showed: a linear correlation between reduction waves in linear voltammetry and phosphate concentration at a constant pH value; that phosphate ions induced considerable anaerobic corrosion of mild steel, which was sensitive to hydrogen concentration in the solution; and that the corrosion potential of stainless steel in presence of phosphate was shifted to more negative values as molecular hydrogen was added to the atmosphere in the reaction vessel. Phosphate species, and possibly other weak acids present in biofilms, are suggested to play an important role in the anaerobic corrosion of steels via a reversible mechanism of electrochemical deprotonation that may be accelerated by hydrogen removal.

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The use of phosphate to generate H-atoms at pH 5–8 as determined by photocurrents: electrochemical properties of H-atoms

Cited by 9 publications

References 7 publications

Electrochemical deprotonation of phosphate on stainless steel

Electrochemical deprotonation of phosphate on stainless steel

Hydrogen production by electrolysis of a phosphate solution on a stainless steel cathode

Role of the reversible electrochemical deprotonation of phosphate species in anaerobic biocorrosion of steels

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