http://www.cnr.it/ontology/cnr/individuo/prodotto/ID296267

Carbothermal transformation of TiO2 into TiOxCy in UHV: Tracking intrinsic chemical stabilities (Articolo in rivista)

Type

Articolo in rivista (Classe)
Prodotto della ricerca (Classe)

Label

Carbothermal transformation of TiO2 into TiOxCy in UHV: Tracking intrinsic chemical stabilities (Articolo in rivista) (literal)

Anno

2014-01-01T00:00:00+01:00 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

10.1021/jp506728w (literal)

Alternative label

Calvillo L.; Fittipaldi D.; Rüdiger C.; Agnoli S.; Favaro M.; Valero-Vidal C.; Di Valentin C.; Vittadini A.; Bozzolo N.; Jacomet S.; Gregoratti L.;, Kunze-Liebhäuser J.; Pacchioni G.; Granozzi G. (2014)
Carbothermal transformation of TiO2 into TiOxCy in UHV: Tracking intrinsic chemical stabilities
in Journal of physical chemistry. C; American Chemical Society, Washington, DC (Stati Uniti d'America)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

Calvillo L.; Fittipaldi D.; Rüdiger C.; Agnoli S.; Favaro M.; Valero-Vidal C.; Di Valentin C.; Vittadini A.; Bozzolo N.; Jacomet S.; Gregoratti L.;, Kunze-Liebhäuser J.; Pacchioni G.; Granozzi G. (literal)

Pagina inizio

22601 (literal)

Pagina fine

22610 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url

http://pubs.acs.org/doi/abs/10.1021/jp506728w (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

118 (literal)

Rivista

Journal of physical chemistry. C (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo

39 (literal)

Note

ISI Web of Science (WOS) (literal)
Scopu (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

1,4,5,14 : Department of Chemical Sciences, Universit di Padova, Via Marzolo 1Padova, Italy / 2,7,13 : Department of Material Science, Università Milano-BicoccaMilan, Italy / 3,6,12 : Physics Department E19, Technical University of Munich, James-Franck-Str.Garching, Germany / 3,6,12 : Institute of Physical Chemistry, University of Innsbruck, Innrain 80-82Innsbruck, Austria 8 : CNR-IENI, Via Marzolo 1Padova, Italy / 9,10 : MINES ParisTech, PLS - Research University, CNRS UMR 7635, CS 10207 rue Claude DaunesseSophia Antipolis Cedex, France / 11 : Elettra - Sincrotrone Trieste SCpA, Area Science Park, SS14-Km163.5Trieste, Italy (literal)

Titolo

Carbothermal transformation of TiO2 into TiOxCy in UHV: Tracking intrinsic chemical stabilities (literal)

Abstract

The conversion of anodic TiO2 films into TiOxCy in ultrahigh-vacuum (UHV) has been traced by photoemission spectroscopy in order to optimize the process parameters and study the different phase stabilities. In addition, density functional theory (DFT) calculations have been performed in order to elucidate the main questions about TiOxCy composition and stability. The experimental data indicate that the anodic TiO2 film is stable both in UHV and ethylene background up to ca. 600 K, and at this temperature, it starts to reduce leading to suboxide TiOx species. Above ca. 750 K, the formation of TiOxCy starts, since the oxygen vacancies begin to be replaced by carbon atoms. A surface enrichment in TiO2 and elemental carbon has been detected on the converted TiOxCy film at room temperature. Real-time measurements have shown that this phenomenon takes place during the cool down process and DFT calculations suggest a possible explanation: as the temperature decreases below ca. 750 K (temperature at which the formation of TiOxCy starts), the TiOxCy phase is not thermodynamically stable, and it decomposes into TiO2 and elemental carbon. The comparison of the experimental valence band data with DFT results has also allowed to establish that the film surface is not homogeneous and that segregation of TiO and TiC systems may take place. On the other hand, the local compositional study carried out by scanning photoelectron microscopy has shown that the conversion of the film is not homogeneous but depends on the grain orientation, in particular crystallites with an orientation close to <21?1?0> and <101?0> planes show a higher grade of conversion. Both experimental and DFT data validate the use of TiOxCy as an innovative support for electrocatalysis. (literal)

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