Reactions of Hydrous Titanium Oxide Colloids with Strong Oxidizing Agents

Tijana Rajh, Zoran V. Saponjic, Olga I. Micic

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

The absorption spectra of the transients formed in the reactions of titanium hydrous oxide with SO4•-, Tl2+, or OH* species in alkaline aqueous solution have been studied by using the pulse radiolysis technique. Direct hole capture via interfacial electron transfer from colloidal titanium hydrous oxide to SO4•- radicals leads to the formation of a product which has the broad absorption spectrum with an onset at about 480 nm rising steeply toward the UV region. A completely different absorption spectrum was found for the hydroxyl radical adduct formed by the reaction of OH* with titanium hydrous oxide that has a maximum at 620 nm. This maximum disappears in acidic solution at pH 3 with assistance of H+aq which transforms the OH adduct to the product the same as that formed in the reaction with SO4•-. The low-weight aggregates of titanium hydroxide also react with OH* radicals, and in the alkaline solution a similar transient spectrum with a maximum at 570 nm was obtained. In neutral and alkaline solutions the absorption spectra of transients formed in the reactions of OH*, Tl2+, or SO4•- with TiO2 do not appear to be dependent upon the mode of the colloid preparation. However, decay kinetics of these transients are very sensitive to surface chemistry.

Original languageEnglish (US)
Pages (from-to)1265-1270
Number of pages6
JournalLangmuir
Volume8
Issue number5
DOIs
StatePublished - May 1 1992
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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