Size effect on thermal desorption of CO from Pt nanostructures on graphite

Julukian, Armen; Fadnes, T.; Raaen, S.; Balci, M.

doi:10.1063/1.3596572

Cited by 3 publications

(3 citation statements)

References 21 publications

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“…22 On the contrary, however, from a recent CO adsorption study of Pt particles grown on HOPG, lower CO desorption temperatures were observed for smaller particle sizes, suggesting a decreasing CO binding energy for decreasing particle size. 23 This latter result is comparable to the decrease in binding energy of CO with decreasing nanoparticle size for Pd nanoparticles supported on Fe3O4, observed by microcalorimetry. 24 From the TPD spectra of our nanoparticles in Figure 4, there is no clear indication of a size dependence to the binding energy.…”

Section: ■ Discussionsupporting

confidence: 66%

“…For example, it has been reported that oxygen atoms bind more strongly to small Pt particles than to larger Pt particles . On the contrary, however, from a recent CO adsorption study of Pt particles grown on HOPG, lower CO desorption temperatures were observed for smaller particle sizes, suggesting a decreasing CO binding energy for decreasing particle size . This latter result is comparable to the decrease in binding energy of CO with decreasing nanoparticle size for Pd nanoparticles supported on Fe3O4, observed by microcalorimetry .…”

Section: Discussionmentioning

confidence: 75%

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Structural Modification of Platinum Model Systems under High Pressure CO Annealing

et al. 2012

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Using temperature-programmed desorption experiments, we have studied the coordination dependent adsorption of CO on a platinum (Pt) single crystal, and mass-selected Pt nanoparticles in the size range of 3 to 11 nm, for CO dosing pressures in 10–7 mbar and mbar ranges. From low pressure CO adsorption experiments on the Pt(111) crystal, we establish a clear link between the degree of presputtering of the surface prior to CO adsorption, and the amount of CO bound at high temperature. It was found that for rougher surfaces, i.e., with more undercoordinated surface atoms, a feature appears in the CO desorption spectra at high temperature. The result is consistent with literature results from stepped single crystals that have found high temperature CO desorption features due to the presence of undercoordinated step and kink sites on the crystal facets. For the nanoparticles, a study of the dependence of the CO desorption profile with particle size found more prominent high temperature CO desorption features as the nanoparticle size was decreased, consistent with the expectation for a higher proportion of undercoordinated sites at smaller particle sizes. Thus, for both systems there is a clear relation between surface atom coordination, and the desorption temperature of CO. Investigation of these structural features was then made for CO dosing pressures in the mbar range. Intriguingly, from the mbar pressure experiments it was observed that elevated CO pressures enhanced the annealing of the Pt(111) surface, but on the otherhand, caused an apparent roughening of the nanoparticles.

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Section: ■ Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 75%

Structural Modification of Platinum Model Systems under High Pressure CO Annealing

et al. 2012

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“…[12][13][14] In a previous study, we have shown that the Pt core level shifts depend on the effective average size of the Pt structures. 15 The present paper focuses on the formation and postgrowth relaxation of self-assembled Pt nanostructures in the early stages of growth by thermal evaporation onto substrates of pyrolytic graphite. From SEM, AFM, and XPS analyses, we report here on the formation of ultrasmall nanostructures as well as their evolution into nanodendrites/fractals as a function of Pt amount deposited and average fractal dimension.…”

Section: Introductionmentioning

confidence: 99%

Formation of dendritic Pt nanostructures on graphite

Julukian

Raaen

Franke

2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Formation of unique shapes and geometries was obtained by evaporation of platinum onto a polycrystalline graphite foil. This study was done using scanning electron microscopy, atomic force microscopy, and photoelectron spectroscopy. The evolution of complex nanostructures was observed for various amounts of Pt deposition, and the observed structures were discussed in terms of the average fractal dimension. The fractal dimension was found to increase with increasing deposition of Pt and was found to be in the range from 1.2 to 1.6 in the submonolayer coverage regime as investigated. The changes in the average fractal dimension were correlated with the corresponding changes of the average size and width of the branches of the structures. A logarithmic dependence of the average size of the deposited structures on corresponding amount Pt deposited was found.

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Pt nanoclusters stabilized by N-doped carbon nanofibers for hydrogen production from formic acid

Liu

Bulushev

Podyacheva

et al. 2013

Journal of Catalysis

131

109

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Size effect on thermal desorption of CO from Pt nanostructures on graphite

Abstract: Articles you may be interested inHydrogen trapping state associated with the low temperature thermal desorption spectroscopy peak in hydrogenated nanostructured graphite J. Appl. Phys.

Cited by 3 publications

References 21 publications

Structural Modification of Platinum Model Systems under High Pressure CO Annealing

Structural Modification of Platinum Model Systems under High Pressure CO Annealing

Formation of dendritic Pt nanostructures on graphite

Pt nanoclusters stabilized by N-doped carbon nanofibers for hydrogen production from formic acid

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