Auger and photoemission investigations of the platinum-SrTiO3(100) interface: Relaxation and chemical-shift effects

Partial reduction of Si(IV) in SiO2 thin film by deposited metal particles: an XPS study

“…This difference apparently would be accounted for by the initial state (chemical) effect in the SiO 2 -supported system, and the sign means that there is a charge transfer from Au to SiO 2 . For Pt-TiO 2 , Bahl et al 7 found a 0.5 eV chemical shift for SrTiO 3 -supported Pt, whereas Huizinga et al 22 found no chemical shift for Pt supported on TiO 2 . The shift values also are dependent on the metal particle size, and may decrease significantly with an increase of metal-metal coordination number or an increase of metal loading.…”

“…Bahl et al 7 experimentally examined XPS spectra of Pt supported on SrTiO 3 and found that, after taking into account the final state contribution, there is a net charge transfer of 0.6 electrons from the support oxide to a supported Pt atom. They showed further that, on a slightly sputterreduced SrTiO 3 , the deposition of Pt oxidizes the surface Ti cations, thus demonstrating that the charge transfer is between the deposited metal and the support cation.…”

“…13 It is interesting to note that, although most of these experimental works examine the changes that occur on the supported metal particles in detail, they do not detect the changes that occur on the support itself when the metal particles are deposited, with the exception of Ref. 7. One reason for the lack of studies on electronic metal-support interactions from the support side may be that when electron spectroscopy was employed for a such purpose the background signals originating from the support regions that are not in direct contact, and hence not strongly interacting with the metal particles, are too large to detect the electronic interactions that may be present in the system.…”

“…Thus Escard et al 6 deposited Ir on various support oxide surfaces and found that the apparent 4f binding energy of the supported Ir shows a blue shift compared to that of bulk Ir, and the extent of the blue shift varied with the Fermi energies of the support oxide materials. Bahl et al 7 examined the Pt 4f spectrum from the Pt-SrTiO 3 system and found that, after the relaxation effect correction, there is a net charge transfer between Pt particles and the support oxide. Similar charge transfer has been observed in Ni-TiO 2 Cu-ZnO 12 systems.…”

Katalizátorok felületének jellemzése röntgen-fotoelektron spektroszkópiával

“…A részecskeméret csökkenésével párhuzamosan egyre kisebb szerepet játszik a szomszédos atomok vegyértékelektronjai által biztosított extra-atomi relaxációs hatás (screening effect), így a mért kötési energia egyre inkább az izolált atomokra vonatkozó érték felé tolódik el [111][112][113]. Bahl és munkatársai platinát vizsgáltak SrTiO 3 egykristály felületen és a Pt 4f pályák kötési energiájának csök-kenéséről számoltak be a Pt borítottság növekedésével [114].…”