Evidence for an active oxygen species on Au/TiO 2(1 1 0) model catalysts during investigation with in situ X-ray photoelectron spectroscopy
Dumbuya K, Cabailh G, Lazzari R, Jupille J, Ringel L, Pistor M, Lytken O, Steinrück HP, Gottfried M (2012)
Publication Type: Journal article
Publication year: 2012
Journal
Original Authors: Dumbuya K., Cabailh G., Lazzari R., Jupille J., Ringel L., Pistor M., Lytken O., Steinrück H.-P., Gottfried J.M.
Publisher: Elsevier
Book Volume: 181
Pages Range: 20-25
Journal Issue: 1
DOI: 10.1016/j.cattod.2011.09.035
Abstract
The influence of oxygen (O ) and carbon monoxide (CO) on Au nanoparticles supported on TiO (1 1 0) in the size range of 2-3 nm has been studied using X-ray photoelectron spectroscopy (XPS) and in situ (high pressure) XPS at 300 K for O and/or CO pressures of 0.1-1 mbar. These experiments were aimed at revisiting Au 4f core level shifts as reported in the literature and most importantly, to establish the dependence of the core-level shifts on the knowledge that there exists a maximum in reactivity for CO oxidation. Two samples were prepared with a coverage corresponding to that maximum (Au coverage 0.14-0.2 ML, particle size estimated to ∼2-2.5 nm) while a third sample was expected to be less reactive (Au coverage 0.4 ML, particle size estimated to ∼3.3 nm). At elevated O pressures, a new Au 4f component at higher binding energy (2.4-2.6 eV relative to the Au(0) bulk signal) evolved at all particle sizes. Its appearance was attributed to a radiation-induced activation of oxygen and simultaneous oxidation of gold. The activation was much more efficient on the ∼2-2.5 nm particles. The relative intensity of the oxide component depended strongly on O pressure and, thus, on the equilibrium coverage of O . While not present in 0.1 mbar O regardless of exposure time and particle size, it dominated the Au 4f spectrum of particles ∼2-2.5 nm in size at 1 mbar oxygen pressure. This pressure-dependent formation reconciles previously conflicting XPS data. Finally, the activated oxygen species were very reactive toward CO as manifested by the rapid disappearance of the new Au 4f component in a 1:1 mixture of CO and O . The rates of evolution and consumption of this component were found to depend on gold coverage (and thus, particle size) and were highest for the smaller particles. © 2011 Elsevier B.V. All rights reserved.
Authors with CRIS profile
Martina Pistor
Lehrstuhl für Physikalische Chemie II
Ole Lytken
Lehrstuhl für Physikalische Chemie II
Hans-Peter Steinrück
Lehrstuhl für Physikalische Chemie II
Additional Organisation(s)
Involved external institutions
France (FR)How to cite
APA:
Dumbuya, K., Cabailh, G., Lazzari, R., Jupille, J., Ringel, L., Pistor, M.,... Gottfried, M. (2012). Evidence for an active oxygen species on Au/TiO 2(1 1 0) model catalysts during investigation with in situ X-ray photoelectron spectroscopy. Catalysis Today, 181(1), 20-25. https://dx.doi.org/10.1016/j.cattod.2011.09.035
MLA:
Dumbuya, K., et al. "Evidence for an active oxygen species on Au/TiO 2(1 1 0) model catalysts during investigation with in situ X-ray photoelectron spectroscopy." Catalysis Today 181.1 (2012): 20-25.
BibTeX: Download