A first principles analysis of CO oxidation over Pt and Pt66.7%Ru33.3% (111) surfaces

Desai, Sanket; Neurock, Matthew

doi:10.1016/j.electacta.2003.05.001

Cited by 118 publications

(81 citation statements)

References 53 publications

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“…The similar conclusion was reached by Desai and Neurock [22]. They calculated the reaction energies for the CO ?…”

Section: Two Model Varietiessupporting

confidence: 59%

“…In this way the hydroxyl intermediate can diffuse on the surface. This assumption is in correspondence to the findings of Desai and Neurock [22]. They investigated the interaction of water with a PtRu surface.…”

Section: The Mechanism Of Co Strippingmentioning

confidence: 51%

“…As a result the Ru-OH is converted to Ru-H 2 0, whereas the Pt-water is converted to Pt-OH. In this way the hydroxyl intermediate can diffuse on the surface [22] and can be considered to be homogeneously distributed on the surface. This assumption is valid for well-mixed Pt:Ru surfaces, which corresponds to a kind of catalyst used in the present study (Pt:Ru 1:1).…”

Section: The Mechanism Of Co Strippingmentioning

confidence: 99%

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A method for rough estimation of the catalyst surface area in a fuel cell

2008

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A method for a rough estimation of the catalyst surface area in a fuel cell is developed. It is based on the deconvolution of experimental CO oxidation data by use of a mathematical model. The kinetic parameters of the model are determined by fitting the experimental curves. The experimental data are collected at different sweep rates (2-100 mV s -1 ) and at different temperatures (room -60.0°C). The model can predict the sweep rate dependence of the CO oxidation onset potential, the peak current, the peak potential and the peak broadness. The model is further used for the prediction of the baseline in the presence of CO and for calculation of the CO charge consumed up to half peak potential. It is obtained that the latter value is constant at different sweep rates and that the baseline deviates from linearity already at low sweep rates (2 mV s -1 ), but not very significantly (2.0% in comparison to 8.8% at 100 mV s -1 , based on calculated CO charge). It is suggested that lower sweep rates should be used for experimental surface area determination.Width of the X-ray diffraction peak at half height/rad B r 2hWidth of the X-ray diffraction peak at half height for a standard compound/rad c DL Me Double layer capacitance of metal surface/mF d Average particle size/nm e

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“…The similar conclusion was reached by Desai and Neurock [22]. They calculated the reaction energies for the CO ?…”

Section: Two Model Varietiessupporting

confidence: 59%

Section: The Mechanism Of Co Strippingmentioning

confidence: 51%

Section: The Mechanism Of Co Strippingmentioning

confidence: 99%

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A method for rough estimation of the catalyst surface area in a fuel cell

2008

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“…Since the oxidation process takes place at very localized sites where OHads and COads species can interact, the mean field L−H-type mechanism is fulfilled only if CO diffusion on the surface is fast [23]. Ab initio results for the CO electro-oxidation on Pt(111) have also proposed that adsorbed OH oxidizes CO molecules [24][25][26].…”

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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“…10 CO adsorption is also important in CO oxidation, which occurs in automobile catalytic converters, 11 in preferential CO oxidation (PROX reaction) in hydrogen feeds, 12 and in CO hydrogenation, the critical step in Fischer-Tropsch processes. 13 DFT has been used to study adsorption of CO on metal surfaces, such as Pt(111), [14][15][16][17] on Pt(111) overlayers, 18,19 and on metal nanoparticles. 20 For example, Sadek and Wang 21 have investigated CO adsorption on Pt/Au clusters containing two to four atoms, The Journal of Physical Chemistry C ARTICLE while Song et al 22 have reported adsorption energies for CO on Pt/Au clusters of up to seven atoms.…”

Section: ' Introductionmentioning

confidence: 99%

CO Adsorption on Noble Metal Clusters: Local Environment Effects

et al. 2011

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Bimetallic catalysts are useful because of their versatility, such as the ability to tune their catalytic activity and selectivity by varying properties such as composition, particle size, and support. 1 In particular, Pt-Au catalysts have been shown to exhibit enhanced activity and selectivity in specific reactions when compared to monometallic catalysts. For example, Dimitratos et al. 2 showed that carbon-supported Pt-Au has higher catalytic activity for the oxidation of glycerol than carbon-supported Pt and that the catalyst preparation method affects the selectivity. Selvarani et al. 3 determined that the optimum Pt:Au ratio for carbon-supported Pt-Au as a direct methanol fuel cell catalyst is 2:1, at which composition the catalyst delivers a peak power density 1.5 times that of pure Pt. Comotti et al. 4 found a turnover frequency of 60 h -1 for the oxidation of glucose over pure platinum, while a Pt-Au alloy with Au:Pt ratio of 2:1 yields a turnover frequency of 924 h -1 . The authors also found that, for 7 different Au:Pt ratios ranging from 4 to 0.25, the minimum and maximum turnover frequencies are 240 and 924 h -1 , observed for Au:Pt ratios of 1 and 2, respectively. It is likely that these results depend on the atomic arrangement on the surface of the bimetallic nanoparticles used as catalysts. Unfortunately, direct experimental visualization of the composition and structure of nanoparticle surfaces is at present problematic, especially at operating conditions. Techniques such as high-energy resonant X-ray diffraction can be used to probe the structure of bimetallic catalysts. 5 Molecular simulations could be useful to interpret such experiments and also identify the local structure of supported mono-and bimetallic nanoparticles. [6][7][8] For example, we have previously used molecular dynamics (MD) simulations to study the effect of composition and support geometry on the properties of Pt-Au nanoparticles containing 250 atoms, 9 finding that it should be possible to tailor the distribution of atoms by manipulating nanoparticle composition and support geometry. This could lead to greater control of catalyst selectivity by maximizing the active sites on the nanoparticle surface that catalyze a certain reaction.In order to link our previous MD results to experimentally verifiable measurements, we report here ab initio density functional theory (DFT) calculations for CO adsorption on Pt-Au clusters. CO is often employed as a probe molecule because its adsorption energy and C-O stretching frequency depend on the adsorption site, as can be observed experimentally via, e.g., Fourier transform infrared spectroscopy. 10 CO adsorption is also important in CO oxidation, which occurs in automobile catalytic converters, 11 in preferential CO oxidation (PROX reaction) in hydrogen feeds, 12 and in CO hydrogenation, the critical step in Fischer-Tropsch processes. 13 DFT has been used to study adsorption of CO on metal surfaces, such as Pt(111), [14][15][16][17] on Pt(111) overlayers, 18,19 and on metal nanoparticles. ...

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A first principles analysis of CO oxidation over Pt and Pt66.7%Ru33.3% (111) surfaces

Cited by 118 publications

References 53 publications

A method for rough estimation of the catalyst surface area in a fuel cell

A method for rough estimation of the catalyst surface area in a fuel cell

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

CO Adsorption on Noble Metal Clusters: Local Environment Effects

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