Dual Reactivity of Step-Bound Carbon Monoxide during Oxidation on a Stepped Platinum Electrode in Alkaline Media

Garcı́a, Gonzalo; Koper, Marc T. M.

doi:10.1021/ja9009869

Cited by 62 publications

(101 citation statements)

References 15 publications

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“…A second difference with the other platinum single crystal electrodes is that the presence of prewaves is only observed for n<12 [42,46], and was previously observed for the Pt(100) electrode [42,44]. The differences may arise from the different coverages obtained in this work.…”

Section: Co Oxidationmentioning

confidence: 56%

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On the behavior of the Pt(100) and vicinal surfaces in alkaline media

Arán‐Ais

Figueiredo

Vidal‐Iglesias

et al. 2011

Electrochimica Acta

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Abstract:We address in this paper a voltammetric study of the charge transfer processes characteristic of Pt(100) and vicinal surfaces in alkaline media. The electrochemical behavior of a series of stepped surfaces of the type Pt(S)[n(100)×(111)] has been characterized using cyclic voltammetry at different pHs, charge displacement measurements and FTIR experiments for adsorbed CO. The results from these techniques allow assigning the different peaks appearing in the voltammogram to hydrogen and /or OH adsorption on the different sites characteristic of these surfaces, namely, terrace and step sites. Additionally, the potential of zero total charge (pztc) of the electrodes was also determined. The resulting pztc values shift to more negative values when the step density increases on the surface up to n=5. FTIR spectroscopy experiments have been used to monitor the adsorption of CO on the different surfaces as well as the consequent CO oxidation, accompanying a positive potential sweep. The oxidation of adsorbed CO on (100) terraces is catalyzed by the presence of the (111) steps. The FTIR spectra revealed that CO is mostly bonded in bridge configuration at low potentials interconverting to on-top when the electrode potential is increased.

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Section: Co Oxidationmentioning

confidence: 56%

“…For the surfaces vicinal to the Pt(111) electrode, stripping voltammetry for CO shows peaks corresponding to the oxidation of CO on the terraces, step and kink sites [42][43][44]. However, in this case, a single peak is always observed (aside from the presence of occasional prewaves).…”

Section: Co Oxidationmentioning

confidence: 99%

On the behavior of the Pt(100) and vicinal surfaces in alkaline media

Arán‐Ais

Figueiredo

Vidal‐Iglesias

et al. 2011

Electrochimica Acta

View full text Add to dashboard Cite

show abstract

“…As previously stated in the introduction section, there is a clear relationship between the oxidation peak potential and the adsorption site on stepped Pt surfaces having (111) terraces and monoatomic (110) or (100) steps [20,21]. Based on experimental results, the slow CO oxidation releases first the (111) terrace sites and, only when all the terrace sites are free, CO oxidation occurs on the (110) and (100) step sites.…”

Section: Site Co Occupancy On Shape-controlled Pt Nanoparticles and Imentioning

confidence: 81%

“…For stepped and kinked Pt surfaces with (111) terraces and (110) or (100) steps, up to three different CO oxidation peaks located at 0.58, 0.70 and 0.78 V (vs RHE) have been observed and assigned to the CO electro-oxidation with kink/step sites and (111) terrace sites, respectively, [18]. Recently, a series of experiments have allowed reassigning the site release for a particular oxidation peak [20,21]. For Pt(111) vicinal surfaces, for which electronic effects might modify both stability and structure of adsorbed CO at the (111) terrace sites, CO adsorbs firstly at low-coordination sites and its oxidation occurs preferentially at (111) terrace sites close to the lower side of the low-coordination (kink/step) sites [20].…”

Section: Introductionmentioning

confidence: 99%

On the behavior of CO oxidation on shape-controlled Pt nanoparticles in alkaline medium

Farias

Vidal‐Iglesias

Solla-Gullón

et al. 2014

Journal of Electroanalytical Chemistry

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In this work, the behavior of the CO electro-oxidation reaction on shape-controlled Pt nanoparticles in alkaline medium was examined in order to understand the effect of the surface structure on this reaction. A series of experiments using Pt nanoparticles of different surface structures/shapes was used and the results obtained were compared with the previous knowledge gained from stepped platinum single crystal electrodes. Independently of the preferential orientation of the nanoparticles, the CO oxidation voltammetry exhibits two main peaks: one at ca. 0.56-059 V and the second one at 0.66 -0.67 V, being the intensity of the peaks dependent on the shape of the nanoparticle. These two peaks have been assigned to the oxidation of CO on the (111) terraces and on the rest of the sites, respectively. The appearance of two differentiated peaks reveals that these (111) terraces and the rest of the sites on the nanoparticle surface behave independently of the presence of the other type of sites, that is, they are not connected. The results are discussed considering the effects of the surface mobility of CO and of the OH adsorption properties on the different sites in the oxidation peaks.

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“…Whereas in acidic media, only one oxidation peak is found in the oxidation voltammogram, two or even three peaks appear in basic solutions [27], depending on the different type of sites present on the surface. Thus, the peak corresponding to CO oxidation on (111)-steps in alkaline media appears at lower potentials than on (100)-steps or on (111) terraces [28,29]. This clearly indicates that the reactivity of steps is indeed different depending on their symmetry.…”

Section: Introductionmentioning

confidence: 91%

CO oxidation on stepped-Pt(111) under electrochemical conditions: insights from theory and experiment

Busó-Rogero

Herrero

Bandlow

et al. 2013

Phys. Chem. Chem. Phys.

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The co-adsorption of CO and OH on two Pt stepped surfaces vicinal to the (111) orientation has been evaluated by means of density functional theory (DFT) calculations. Focusing on Pt(533) and Pt(221), which contain (100) and (111)-steps, respectively, we find that (111)-steps are more reactive towards CO oxidation than surfaces containing (100)-steps. The DFT results are compared with electrochemical experiments on the CO adsorption and oxidation on these vicinal surfaces.

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Dual Reactivity of Step-Bound Carbon Monoxide during Oxidation on a Stepped Platinum Electrode in Alkaline Media

Cited by 62 publications

References 15 publications

On the behavior of the Pt(100) and vicinal surfaces in alkaline media

On the behavior of the Pt(100) and vicinal surfaces in alkaline media

On the behavior of CO oxidation on shape-controlled Pt nanoparticles in alkaline medium

CO oxidation on stepped-Pt(111) under electrochemical conditions: insights from theory and experiment

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