Structural effects on the oxidation of HCOOH by bismuth modified Pt(111) electrodes with (110) monatomic steps

Smith, Sean P. E.; Abruña, Héctor D.

doi:10.1016/s0022-0728(98)00447-1

Cited by 53 publications

(24 citation statements)

References 22 publications

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“…For the Pt(111) electrode and vicinal surfaces modified with Bi, As, Te, Sb or Pb a clear increase in the currents with respect to those measured in the clean surface is observed [15,44,45,36,46,47,37,48]. For instance, the currents for a Bi modified surface can be 40 times higher than those measured for the unmodified surface in the absence of poison at the same potential.…”

Section: Effect Of the Adatoms In The Route Through The Active Intermmentioning

confidence: 90%

Fundamental aspects of HCOOH oxidation at platinum single crystal surfaces with basal orientations and modified by irreversibly adsorbed adatoms

Boronat-González

Herrero

Feliu

2013

J Solid State Electrochem

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Abstract.Oxidation of formic acid at Pt(hkl) electrodes with basal orientations and modified by irreversibly adsorbed adatoms is revisited. It was shown that the adatoms of the nitrogen group could enhance the electrocatalytic activity through long range electronic effects in the case of Pt (111) substrates or through shorter third body effects when adsorbed at Pt(100) electrodes. In both cases it appears that free platinum sites were required. Special attention is given here to the reactivity at Pt(110) substrates. It is found that maximum electrocatalysis is observed at fully blocked surfaces. This result points out again structure sensitivity effects for this characteristic reaction. Unlike the more compact planes, in which the enhancement of the oxidation rate was explained through essentially rigid models for the adlayer, it is suggested that the resulting enhancement observed at Pt(110) substrates could be explained if some adatom mobility is considered.

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Section: Effect Of the Adatoms In The Route Through The Active Intermmentioning

confidence: 90%

Fundamental aspects of HCOOH oxidation at platinum single crystal surfaces with basal orientations and modified by irreversibly adsorbed adatoms

Boronat-González

Herrero

Feliu

2013

J Solid State Electrochem

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“…The use of foreign metals irreversibly adsorbed onto platinum single-crystal surfaces has allowed control of the selectivity of the dual path mechanism and has given rise to significant enhancements in the current densities for the electro-oxidation of formic acid. ,, In this way studies employing single-crystal platinum electrodes irreversibly modified with Pb, Sb, − Bi, ,− Se, and Pd have been performed. Of these, bismuth-modified Pt(111) electrodes (Bi/Pt(111)) exhibit well-defined voltammetric features, associated with the bismuth adlayer, that are very stable.…”

Section: Introductionmentioning

confidence: 99%

Structural Effects on the Oxidation of HCOOH by Bismuth-Modified Pt(111) Electrodes with (100) Monatomic Steps

1999

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Significant enhancements in the electrocatalytic oxidation of HCOOH are obtained on deliberately stepped platinum surfaces with (111) terraces and (100) monatomic steps when bismuth is deposited on terrace and/or step sites. The bismuth-modified surfaces with higher step densities/narrower terrace widths exhibit higher catalytic activity in the oxidation of HCOOH than surfaces with lower step densities/wider terrace widths, behavior which is opposite to that exhibited by the analogous bare (unmodified) surfaces. For Bi/Pt(544) and Bi/Pt(755), with nine- and six-atom wide (111) terraces, respectively, maximum catalytic behavior occurs when bismuth is deposited on all step sites and partially deposited on the terraces. On the other hand, for Bi/Pt(211) and Bi/Pt(311), with three- and two-atom wide (111) terraces, respectively, maximum catalytic behavior occurs when bismuth is deposited only on the steps, suggesting that a critical ensemble (critical size), two atoms wide, enhances the reactive intermediate pathway for the complete oxidation of HCOOH over the poisoning reaction pathway. Moreover, the potential for the onset of oxidation of HCOOH shifts to less positive potentials as the terrace width of the bismuth-modified surfaces becomes narrower, suggesting a diminution in the activation energy barrier as the ensemble size becomes smaller. Contrary to the behavior on the stepped surfaces, bismuth-modified, polyoriented spherical platinum electrodes, which contain a random distribution of (111), (100), and (110) faces, exhibit a continuous rise in catalytic activity for HCOOH oxidation with bismuth coverage, even at bismuth coverages approaching 100%.

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“…Properties of electrode materials with potential use in direct alcohol fuel cells have been widely investigated in the last decades [1][2][3][4][5][6][7]. The idea of modifying electrode surfaces with foreign metal adatoms has led to significant achievements [1][2][3][8][9][10], not only in terms of structural modification but also in changes to surface electron density and the possibility of developing a bifunctional mechanism involving formation of oxygenated species at the foreign atom sites.…”

Section: Motivationmentioning

confidence: 99%

“…The idea of modifying electrode surfaces with foreign metal adatoms has led to significant achievements [1][2][3][8][9][10], not only in terms of structural modification but also in changes to surface electron density and the possibility of developing a bifunctional mechanism involving formation of oxygenated species at the foreign atom sites. These noteworthy effects should improve catalytic activity, preventing blocking of the electrode surface caused by the presence of reaction intermediates and/or products such as carbon monoxide.…”

Section: Motivationmentioning

confidence: 99%

Selected properties of Pt(111) modified surfaces: A DFT study

Pinto

2015

Electrochemistry Communications

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Structural effects on the oxidation of HCOOH by bismuth modified Pt(111) electrodes with (110) monatomic steps

Cited by 53 publications

References 22 publications

Fundamental aspects of HCOOH oxidation at platinum single crystal surfaces with basal orientations and modified by irreversibly adsorbed adatoms

Fundamental aspects of HCOOH oxidation at platinum single crystal surfaces with basal orientations and modified by irreversibly adsorbed adatoms

Structural Effects on the Oxidation of HCOOH by Bismuth-Modified Pt(111) Electrodes with (100) Monatomic Steps

Selected properties of Pt(111) modified surfaces: A DFT study

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