Charge State of Gold Nanoparticles Supported on Titania under Oxygen Pressure

Abstract

Reversible band bending induced by adsorption of molecular oxygen on TiO2(110) was revealed by studying the charge state of TiO2‐supported Au nanoparticles under O2 pressure by X‐ray photoelectron spectroscopy (see picture). This result is important for correct assignment of charge‐transfer phenomena on catalysts in general, and with regard to the high catalytic activity of Au/TiO2 catalysts in numerous reactions, including CO oxidation.

Band bending and dipole effect at interface of metal-nanoparticles and TiO2 directly observed by angular-resolved hard X-ray photoemission spectroscopy

“…As an example, the deposition of nanoscale Pt onto a TiO 2 film caused a peak shift of 0.25 eV toward a lower binding energy along with upward band bending. A similar peak shift in XPS spectra has been discussed for nanoscale metal/semiconductors junctions such as Pt/TiO 2 , Au/TiO 2 , Pd/TiO 2 , Pt/ZnO, Ni/SiC, metal/GaN, [30][31][32][33][34][35][36] and recently HAXPES was applied to a Ni/Al 2 O 3 /GaAs system. 37 The shift in the corelevel peak position for the metal/semiconductor combination originates from band bending toward the surface.…”

Threshold catalytic onset of carbon formation on CeO2during CO2electrolysis: mechanism and inhibition

“…In addition, the gas peak shied to a lower binding energy, possibly due to a change in the gas adsorption behavior on the carbon-covered surface. 53 The change of Ce 4d spectra during carbon deposition is twofold ( Fig. 3e): rst, the total intensity of the normalized Ce peak decreased as a result of carbon deposition.…”

The Active State of Supported Ruthenium Oxide Nanoparticles during Carbon Dioxide Methanation

“…The gold under-layer provided electronic conductivity to the sample as well as an XPS reference using the Au 4f doublet at 84 eV that could be measured on the exposed gold (in the holes), which was connected to ground. Because we did not observe variation of Ti 2p binding energy of Ti(IV) in TiO 2 , possible apparent binding shifts due to band bending 33 were not taken into account when using Au as a reference.…”