Issue 25, 2010
From the journal:

Physical Chemistry Chemical Physics

Stability and chemisorption properties of ultrathin TiOx/Pt(111) films and Au/TiOx/Pt(111) model catalysts in reactive atmospheres†

Luca Artiglia,a   Thomas Diemant,b   Heinrich Hartmann,b   Joachim Bansmann,b   R. Jürgen Behm,b   Luca Gavioli,cd   Emanuele Cavalierecd  and  Gaetano Granozzi*a  

* Corresponding authors

a Department of Chemical Sciences, via Marzolo 1, University of Padova, Italy

b Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm, Germany

c Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, via dei Musei 41, I-25121 Brescia, Italy

d Laboratorio Nazionale CNR-INFM-TASC, S.S. 14 Km 163.5, 34012 Basovizza (TS), Italy

Abstract

The stability of three ultrathin TiOx/Pt(111) films with different stoichiometry and defectivity and the corresponding Au/TiOx/Pt(111) model catalysts in CO or a CO–O2 (1 : 1) gas mixture up to a pressure of 100 mbar has been investigated. According to previous studies, the ultrathin films proved to be effective substrates to deposit in UHV Au nanoparticles with specific morphologies and lateral sizes ranging between 1 and 6 nm. The films have been characterized before and after the exposure using X-ray photoemission spectroscopy (XPS), low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM). Additional in situ measurements of the CO chemisorption behavior were performed using polarization-modulation infrared reflection–absorption spectroscopy (PM-IRAS). A fully oxidized film is stable in CO and CO–O2 (1 : 1) ambient, while the reduced films undergo an oxidative dewetting process at RT in the latter atmosphere. This process ultimately produces a nano-composite surface, where very tiny (from 0.5 to 3 nm lateral sizes) titania nanograins are mixed with open, uncovered areas of the Pt substrate. IRAS measurements on the corresponding Au/TiOx/Pt(111) model catalysts demonstrated that the CO chemisorption strongly depends on the Au nanoparticle size and morphology, while the actual Ti oxidation state of the oxide support does not seem to play a significant role.

Graphical abstract: Stability and chemisorption properties of ultrathin TiOx/Pt(111) films and Au/TiOx/Pt(111) model catalysts in reactive atmospheres

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Article information

DOI
https://doi.org/10.1039/C000884B
Article type
Paper
Submitted
14 Jan 2010
Accepted
16 Mar 2010
First published
11 May 2010

Phys. Chem. Chem. Phys., 2010,12, 6864-6874

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Stability and chemisorption properties of ultrathin TiOx/Pt(111) films and Au/TiOx/Pt(111) model catalysts in reactive atmospheres

L. Artiglia, T. Diemant, H. Hartmann, J. Bansmann, R. J. Behm, L. Gavioli, E. Cavaliere and G. Granozzi, Phys. Chem. Chem. Phys., 2010, 12, 6864 DOI: 10.1039/C000884B

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