Cooxidation on stepped Pt[n(111)×(111)] electrodes

Lebedeva, N. P.; Koper, Mtm Marc; Herrero, Enrique; Feliu, Juan M.; Santen, van Ra Rutger

doi:10.1016/s0022-0728(00)00149-2

Cited by 279 publications

(372 citation statements)

References 45 publications

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“…The surfaces studied were Pt(15 15 14) with n = 30, Pt(554) with n = 10, Pt(553) with n = 5 and the limiting cases Pt(111) and Pt(110). In the voltammetric study [9], a pronounced catalyzing effect of steps was observed in the CO adlayer oxidation for the entire range of CO coverages as well as for the oxidation of dissolved CO. Figure 1 illustrates how a higher step density lowers the overpotential for CO adlayer oxidation, the difference between peak potentials for Pt(553) and Pt(111) being as high as 0.17 V. This effect has been explained by the preferential formation of oxygen-containing species at the step sites compared to the terrace sites, even when electrode surface is pre-dosed with CO [9]. For a quantitative study of the reaction kinetics of CO adlayer electrooxidation on Pt[n(111) · (111)] chronoamperometry or potential-step experiments were employed [10,11].…”

Section: Co Electrooxidation On Ptmentioning

confidence: 93%

“…In order to systematically investigate the mechanism and the kinetics of the electrooxidation of CO on platinum electrodes, voltammetric [9] and chronoamperometric studies [10,11] were performed on a number Pt[n(111) · (111)] vicinal surfaces. For an fcc metal like platinum, the [n(111) · (111)] surfaces are composed of terraces of (111) orientation, which are (n -1) atoms wide, separated by monoatomic steps of (110) orientation.…”

Section: Co Electrooxidation On Ptmentioning

confidence: 99%

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Mechanisms of Carbon Monoxide and Methanol Oxidation at Single-crystal Electrodes

et al. 2007

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The electrochemical oxidation of carbon monoxide and methanol on single-crystal noble metal electrodes has been studied using cyclic voltammetry, chronoamperometry, in situ FTIR spectroscopy, online electrochemical mass spectrometry, and theoretical methods. The oxidation of CO was found to be enhanced by steps and defects. Furthermore, the surface diffusion rate was found to have a significant influence on the kinetics of the oxidation process: for high diffusion rates, such as the oxidation of CO on platinum, the kinetics can be described by a mean field model, while for low diffusion rates, such as CO oxidation on rhodium in sulfuric acid, a nucleationand-growth model was found to be more suitable. Voltammetric and mass spectrometric measurements on the oxidation of methanol on platinum indicate that steps enhance the overall reaction rate. In general, the selectivity towards the direct oxidation pathway through soluble intermediates was found to be higher in the absence of strongly adsorbing anions. In both perchloric and sulfuric acid, this selectivity was also found to increase with increasing step density. In sulfuric acid, Pt(111) shows the highest relative contribution for the direct pathway of all surfaces studied in that electrolyte. Based on these results, a detailed reaction scheme for the electrochemical oxidation of methanol is presented.

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Section: Co Electrooxidation On Ptmentioning

confidence: 93%

Section: Co Electrooxidation On Ptmentioning

confidence: 99%

Mechanisms of Carbon Monoxide and Methanol Oxidation at Single-crystal Electrodes

et al. 2007

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“…The oxidation kinetics of adsorbed CO on Pt single crystal-electrodes has been extensively studied both in the absence [8][9][10][11][12][13][14][15][16][17][18] and in the presence of dissolved CO in acidic solutions [19][20][21][22]. These studies have revealed that the CO oxidation on Pt(111) and vicinal electrodes takes place according to the mean field Langmuir−Hinselwood (L−H) mechanism [10,11,14,16], in which adsorbed CO reacts with an adsorbed OH species originating from waters' dissociative adsorption.…”

Section: Introductionmentioning

confidence: 99%

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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“…These configurational terms are explicitly subtracted from the adsorbate chemical potential in Eqns. (7) and (10), in order to increase the linearity of ∆ , 0 vs. at low and high coverages and allow abetter estimation of all deviations from ideality, especially those ones owing to lateral interactions [17,36,46].…”

Section: Thermodynamic Analysis Of Temperature Effects In the Low Potmentioning

confidence: 99%

“…2016, 646: 269-281. doi:10.1016/j.susc.2015. 10.003 electrochemical reactions, defects sites are often thought to be the most active sites for catalytic reactions involving bond breaking and making steps [10].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic properties of hydrogen–water adsorption at terraces and steps of Pt(111) vicinal surface electrodes

Gómez–Marín

Feliu

2016

Surface Science

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Abstract:In this work, the effect of the temperature on the adsorption states of Pt(111) vicinal surface electrodes in perchloric acid is studied through a thermodynamic analysis. The method allows calculating thermodynamic properties of the interface. In this framework, the concept of the generalized isotherm and the statistical thermodynamics description are applied to calculate formal entropies, enthalpies and Gibbs energies, ∆ 0 , of the adsorption processes at two-dimensional terraces and one-dimensional steps. These values are compared with data from literature. Additionally, the effect of the step density on∆ 0 and on the lateral interactions between adsorbed species, ωij, at terraces and steps is also determined. Calculated ∆ 0 , entropies and enthalpies are almost temperature-independent, especially at steps, but they depend on the step orientation. In contrast, ∆ 0 and ωij at terraces depend on the step density, following a linear tendency for terrace lengths larger than 5 atoms. However, while ∆ 0 increases with the step density, ωij decreases. Results were explaining by considering the modification in the energetic surface balance by hydrogen, Hads, and water, H2Oads, co-adsorption on the electrode, which in turn determines the whole adsorption processes on terraces and steps.

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Cooxidation on stepped Pt[n(111)×(111)] electrodes

Cited by 279 publications

References 45 publications

Mechanisms of Carbon Monoxide and Methanol Oxidation at Single-crystal Electrodes

Mechanisms of Carbon Monoxide and Methanol Oxidation at Single-crystal Electrodes

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

Thermodynamic properties of hydrogen–water adsorption at terraces and steps of Pt(111) vicinal surface electrodes

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