XPS and IR (ATR) analysis of Pd oxide films obtained by electrochemical methods

Tura, J.M.; Regull, Pere; Victori, L.; Castellar, M. Dolors de

doi:10.1002/sia.740110807

Cited by 81 publications

(34 citation statements)

References 10 publications

(1 reference statement)

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“…5, plot b). Depending on the promoter, the binding energy of oxidized Pd in these samples varied in the range of 337.5-337.7 eV which agrees with the data for Pd oxides [22,23].…”

Section: Resultssupporting

confidence: 83%

Liquid phase isomerization of isoprenol into prenol in hydrogen environment

Kogan

Kaliya

Froumin

2006

Applied Catalysis A: General

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“…5, plot b). Depending on the promoter, the binding energy of oxidized Pd in these samples varied in the range of 337.5-337.7 eV which agrees with the data for Pd oxides [22,23].…”

Section: Resultssupporting

confidence: 83%

Liquid phase isomerization of isoprenol into prenol in hydrogen environment

Kogan

Kaliya

Froumin

2006

Applied Catalysis A: General

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“…The changes in the temperature region from 658 K to 778 K can be interpreted in terms of the formation of the bulk oxide phase PdO. Indeed, the position of the Pd 3d 5/2 peak at 336.56 eV is characteristic for bulk PdO [10][11][12][13][14][15][16]. The steep decrease of the O(II) coverage at the temperatures above 765 K corresponds to PdO decomposition.…”

Section: 1in-situ Xps: Heating In Oxygenmentioning

confidence: 99%

In situ XPS study of Pd(111) oxidation at elevated pressure, Part 2: Palladium oxidation in the 10−1mbar range

et al. 2006

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The oxidation of the Pd(111) surface was studied by in situ XPS during heating and cooling in 0.4 mbar O 2 . The in situ XPS data were complemented by ex situ TPD results. A number of oxygen species and oxidation states of palladium were observed in situ and ex situ. At 430 K, the Pd(111) surface was covered by a 2D oxide and by a supersaturated O ads layer. The supersaturated O ads layer transforms into the Pd 5 O 4 phase upon heating and disappears completely at approximately 470 K. Simultaneously, small clusters of PdO, PdO seeds, are formed. Above 655 K, the bulk PdO phase appears and this phase decomposes completely at 815 K. Decomposition of the bulk oxide is followed by oxygen dissolution in the near-surface region and in the bulk. The oxygen species dissolved in the bulk is more favoured at high temperatures because oxygen cannot accumulate in the near-surface region and diffusion shifts the equilibrium towards the bulk species. The saturation of the bulk "reservoir" with oxygen leads to increasing the uptake of the near-surface region species. Surprisingly, the bulk PdO phase does not form during cooling in 0.4 mbar O 2 , but the Pd 5 O 4 phase appears below 745 K. This is proposed to be due to a kinetic limitation of PdO formation because at high temperature the rate of PdO seed formation is compatible with the rate of decomposition.

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“…The change in metal particle size, which is proposed to depend on either the pore structure of zeolite due to the steric confinement or strong interaction between BAS and metallic Pd [12,14,15] can change the binding energy measured by XPS, especially for the particles less than 5 nm [11,16,17]. Furthermore, the change of the chemical environment of the metal changed the binding energy of Pd 3d 5/2 , when Pd electrode was polarized in KOH [10]. The presence of alkali metals lowered the binding energy of Pd 3d 5/2 in Pd/SiO 2 independently of the variations in the metal particle size [18].…”

Section: Introductionmentioning

confidence: 99%

“…Other factors, which can affect the interpretation of the catalyst characterization data are, e.g. metal particle size [8,9], chemical environment of the metal [4,10] and catalyst reduction temperature [4]. Mason [11] proposed the nature of support to be decisive for the binding energies of the metals.…”

Section: Introductionmentioning

confidence: 99%

X-Ray Photoelectron Spectroscopy Investigation of Pd-Beta Zeolite Catalysts with Different Acidities

et al. 2009

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Three different H-Beta zeolites with SiO 2 / Al 2 O 3 molar ratios of 300, 150 and 25 were loaded with palladium by evaporation-impregnation method using Pd(NO 3 ) 2 as a precursor. Dependence between the electronic states of Pd as a function of the acidity of Beta zeolite was studied by XPS for calcined and reduced samples. The dependence of the electronic states of Pd on the support was detected to have a complicated character and to be influenced by various factors such as metal loading, density of the imperfections in the zeolitic framework and proton localization. In calcined zeolites mainly agglomerated PdO and AlPd x O crystallites were detected referring to interaction of palladium with the support. Reduction of PdO led to formation of metallic Pd n clusters, which further reduced to [Pd n -H m ] m? complexes and AlPd x O complexes. The increase of the reduction temperature seems to enhance interactions of Pd n clusters with imperfect [AlO x -] components instead of protons, especially in less acidic samples due to enhanced agglomeration of palladium particles outside the pores of the zeolite. The fraction, size and shape of the formed species were detected to be sensitive to the acidity of the support.

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XPS and IR (ATR) analysis of Pd oxide films obtained by electrochemical methods

Cited by 81 publications

References 10 publications

Liquid phase isomerization of isoprenol into prenol in hydrogen environment

Liquid phase isomerization of isoprenol into prenol in hydrogen environment

In situ XPS study of Pd(111) oxidation at elevated pressure, Part 2: Palladium oxidation in the 10−1mbar range

X-Ray Photoelectron Spectroscopy Investigation of Pd-Beta Zeolite Catalysts with Different Acidities

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