Core binding energies for clusters deposited on different insulating substrates: esca spectra and theoretical electronic structure studies

X-ray photoelectron spectroscopic study of the interaction of supported metal catalysts with NOx

“…For the minimum amount of applied platinum, when the Pt particle size is relatively small, BE(Pt4f 7/2 ) is 72.4 eV. In previous studies, the binding energy of the Pt4f 7/2 line also increased with the decreasing size of platinum particles when Pt was applied to other nonconducting oxide materials such as TiO 2 [7,8] and SiO 2 [9]. For metal nonconducting support systems, this is a common effect; it is generally associated with the final state effect that increases the binding energy of the core levels of the metal because of the less effective screening of the hole, arising from electron photoemission from these levels [10].…”

Structure and Reactivity of Small Metallic and Bimetallic Clusters Hosted in Molecular Sieves

“…It has been claimed for a long time [4][5][6] that metal clusters on acidic supports are electron-deficient which is likely due to the interaction with zeolitic protons or with zeolitic framework oxygen [7,8]. Whether the observed spectral differences between small particles and bulk metals (XPS chemical shifts, CO frequencies, absorption edge in XAFS spectra) reflect metal-support interactions and size effects or more complicated final-state effects is still a matter of debates and controversy [9][10][11][12][13][14]. The progress in understanding these phenomena, however, is an essential part of the elucidation of the structure-function relationship, e.g.…”

Plasma Deposited Electrocatalytic Films with Controlled Content of Pt Nanoclusters

“…It can be observed that the BE and the FWHM values for composite films are systematically higher than those of bulk platinum and increase as Pt content decreases. The shift and broadening of XPS Pt signal can be caused by different factors: (i) presence of oxidized metal, (ii) differential charging on insulating samples, (iii) nanoparticle size effect 33–35. Since oxygen was demonstrated to be bonded to carbon and no differences were detected by recording XPS signals with and without the flood electron gun to compensate an eventual differential charging, variations in the Pt4f 7/2 peak position and broadening can be ascribed only to particle size effects.…”