The Role of Bridge‐Bonded Adsorbed Formate in the Electrocatalytic Oxidation of Formic Acid on Platinum

Osawa, Masatoshi; Komatsu, Keiichi; Samjeské, Gabor; Uchida, Tatsuo; Ikeshoji, Tamio; Cuesta, Ángel; Gutiérrez, C.

doi:10.1002/anie.201004782

Cited by 187 publications

(157 citation statements)

References 38 publications

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“…Those authors proposed that the dominant reaction pathway for formic acid oxidation involves the direct oxidation of formate ions via a weakly adsorbed formate precursor, whereas the bridge-bonded adsorbed formate, which in their interpretation is formed by dissociative adsorption of formic acid, is little active for further oxidation. It should be noted that this latter statement is in complete contrast to earlier proposals of these authors, where the bridge-bonded adsorbed formate was claimed to be the reaction intermediate in the dominant pathway [3][4][5][6] . The decrease of the HCOOH oxidation current above pH ≈ pKa was explained by an increasing site blocking of the surface due to adsorption of hydroxyl species (OHads) and / or surface oxide formation, while the decrease at lower pH values was attributed to the decreasing concentration of HCOO -anions [15] .…”

Section: Effect Of Electrolyte Ph On Hcooh Electro-oxidationcontrasting

confidence: 89%

“…Nonetheless, the nature of the reactive intermediate for the direct pathway is still strongly debated in the literature, especially since adsorbed formate (HCOOads) has been detected by Osawa's group employing in situ Infrared (IR) spectro-electrochemistry [2] . This latter species has been proposed as candidate for the reactive intermediate species in numerous contributions [3][4][5][6][7][8] , while, oppositely, it has been considered as a site-blocking spectator species in other ones [9][10][11][12] . It should be noted that the conclusions were based on essentially equivalent experimental observations.…”

Section: Introductionmentioning

confidence: 99%

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Formic Acid Electrooxidation on Noble‐Metal Electrodes: Role and Mechanistic Implications of pH, Surface Structure, and Anion Adsorption

et al. 2014

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We have investigated the influence of the electrolyte pH on formic acid (HCOOH) electro-oxidation on both polycrystalline Pt and Au electrodes, and on single-crystalline Au electrodes in perchloric and sulphuric acid based electrolytes. On Au electrodes, the potentiodynamic oxidation currents are found to depend in a nonlinear way on the electrolyte pH, in a bell-shaped relation with a maximum of the catalytic activity at the pKa of HCOOH. On polycrystalline Pt electrodes, this feature is not observed and the catalytic activity increases steadily with increasing pH up to pH ≈ 5 followed by a plateau until pH 10, in contrast with recent observations [T. Joo et al., J. Amer. Chem. Soc., 135 (2013) 9991]. In addition, for Au surfaces, the reaction is only weakly influenced by the electrode surface structure, while for Pt structural effects are known to be considerable. Anion effects, in contrast, are much stronger for reaction on Au than for Pt electrodes. Also, it is shown that Pt group metal free Au electrodes do not oxidize molecular hydrogen under reaction conditions. The results are discussed in relation to findings in previous mechanistic studies. Most important, the activity is on both electrodes closely correlated with the concentration of HCOO -anions, for Au with both HCOO -and HCOOH concentrations. Based on these results, a number of mechanistic proposals put forward in earlier studies must be discarded, examples for mechanisms compatible with these results are discussed.

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Section: Effect Of Electrolyte Ph On Hcooh Electro-oxidationcontrasting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Formic Acid Electrooxidation on Noble‐Metal Electrodes: Role and Mechanistic Implications of pH, Surface Structure, and Anion Adsorption

et al. 2014

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“…[8][9][10][11][12][13] Electrocatalytic reactions rates depend on the surface structure of the electrodes. So, Pt(111) electrodes exhibit low activity through the active intermediate and negligible CO formation, whereas Pt(100) surfaces show the highest activity for both routes.…”

Section: Introductionmentioning

confidence: 99%

“…20 It has been pointed out that, in the oxidation process of formic acid on pure platinum electrodes, adsorbed formate plays an important role. This specie has been detected by FTIR [9][10][11][12][13] and voltammetry, 21 coinciding the onset for the oxidation process with that for the adsorption of formate. 21 Also, DFT calculations indicate that adsorbed formate is a key element in the considered oxidation process.…”

Section: Introductionmentioning

confidence: 99%

Oxidation Mechanism of Formic Acid on the Bismuth Adatom-Modified Pt(111) Surface

et al. 2014

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In order to improve catalytic processes, elucidation of reaction mechanisms is essential. Here, supported by a combination of experimental and computational results, the oxidation mechanism of formic acid on Pt(111) electrodes modified by the incorporation of bismuth adatoms is revealed. In the proposed model, formic acid is first physisorbed on bismuth and then deprotonated and chemisorbed in formate form, also on bismuth, from which configuration the C−H bond is cleaved, on a neighbor Pt site, yielding CO 2 . It was found computationally that the activation energy for the C−H bond cleavage step is negligible, which was also verified experimentally.

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“…On the other hand, the reaction route which gives directly CO 2 is called the direct oxidation route. For this route, the nature of the intermediate is still subject of discussion [4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

On the activation energy of the formic acid oxidation reaction on platinum electrodes

Perales-Rondón

Herrero

Feliu

2015

Journal of Electroanalytical Chemistry

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Abstract.A temperature dependent study on the formic acid oxidation reaction has been carried out in order to determine the activation energy of this reaction on different platinum single crystal electrodes, namely Pt(100), Pt(111), Pt(554) and Pt (544) (100) electrode, and the activation values for this process range between 20 and 100 kJ/mol. These results have been explained using a reaction mechanism in which the oxidation of formic acid requires the presence of a pre-adsorbed anion on the electrode surface.

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The Role of Bridge‐Bonded Adsorbed Formate in the Electrocatalytic Oxidation of Formic Acid on Platinum

Cited by 187 publications

References 38 publications

Formic Acid Electrooxidation on Noble‐Metal Electrodes: Role and Mechanistic Implications of pH, Surface Structure, and Anion Adsorption

Formic Acid Electrooxidation on Noble‐Metal Electrodes: Role and Mechanistic Implications of pH, Surface Structure, and Anion Adsorption

Oxidation Mechanism of Formic Acid on the Bismuth Adatom-Modified Pt(111) Surface

On the activation energy of the formic acid oxidation reaction on platinum electrodes

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