Reactivity of Titanium Dioxide with Oxygen at Room Temperature and the Related Charge Transfer.
The measurements of electron work function were applied for in situ monitoring of the charge transfer during oxidation and reduction for well-defined titanium dioxide, TiO, at room temperature. The TiO specimen was initially standardized at 1173 K in the gas phase of controlled oxygen activity, at p...
| Publicado en: | Journal of the American Chemical Society Vol. 130; no. 30; pp. 9984 - 9994 |
|---|---|
| Autores principales: | , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
7/30/2008
|
| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=33835722&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 33835722 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 7/30/2008 vid: 130 iid: 30 pid: 997 pub: American Chemical Society artinfo: ui: 33835722 10.1021/ja7108695 ppf: 9984 ppct: 10 formats: tig: atl: Reactivity of Titanium Dioxide with Oxygen at Room Temperature and the Related Charge Transfer. aug: au: Nowotny, J. Bak, T. Sheppard, L. R. Nowotny, M. K. affil: Centre for Materials Research in Energy Conversion, School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia su: Titanium dioxide Oxygen Charge transfer Collisions (Nuclear physics) Electrons sug: subj: Titanium dioxide Oxygen Charge transfer Collisions (Nuclear physics) Electrons ab: The measurements of electron work function were applied for in situ monitoring of the charge transfer during oxidation and reduction for well-defined titanium dioxide, TiO, at room temperature. The TiO specimen was initially standardized at 1173 K in the gas phase of controlled oxygen activity, at p(O) = 10 Pa, and then cooled down in the same gas phase. The work function changes were monitored during oxidation at room temperature at p(O) = 75 kPa and subsequent reduction at p(O) = 10 Pa. It is shown that oxidation of TiO at room temperature results in fast oxygen chemisorption, involving initially the formation of singly ionized molecular oxygen species, followed by the formation of singly ionized atomic oxygen species, and subsequent slow oxygen incorporation. Although all these processes lead to work function increase, the components of the work function changes related to the individual processes may be distinguished based on different kinetics. The obtained work function data indicate that oxidation results in rapid surface coverage with singly ionized molecular oxygen species, which are subsequently dissociated leading to the formation of singly ionized atomic species. The related chemisorption equilibria are established within 2 and 5 h, respectively. Oxygen incorporation leads to slow work function changes, which achieve a maximum within 100 h. The determined work function data were assessed by using a theoretical model that describes the electrical effects related to different mechanisms of TiO oxidation. The work function data indicate that oxygen incorporation leads to structural changes of the outermost surface layer resulting, in consequence, in a change of the external work function component. Reimposition of the initial gas phase, p(O) = 10 Pa, leads to partial desorption of weakly adsorbed molecular species formed during oxidation. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2008 holdings: @attributes: islocal: N |
|---|