Superoxide Radical Formed on the TiO2 Surface Produced from Ti(OiPr)4 Exposed to H2O2/KOH

Rimma I. Samoilova, Sergei A. Dikanov

Research output: Contribution to journalArticlepeer-review

Abstract

In this study, the superoxide radical O2•− formed by treating Ti(OR)4 (R = iPr, nBu) with H2O2 in the presence of KOH was detected in the EPR spectra. The g-tensor of this radical differs from the typical values reported for a superoxide on various TiO2 surfaces. On the other hand, similar g-tensor components g||(zz = 2.10 ± 0.01, g⊥ = 2.005 ± 0.003 assigned to the O2•− were previously observed for radicals in aqueous solutions in the presence of K2O, alkaline solutions of DMSO, and water/DMSO mixtures. A common factor in all these systems is the presence of alkali ions. However, there was no structural support for the possible interaction of alkali ions with a superoxide in these systems. The use of multifrequency pulsed EPR techniques in this work revealed the stabilization of the O2•− near the K+ ion and its involvement in a strong hydrogen bond with the surface. These findings are consistent with the features previously reported for superoxides on a Na pre-covered MgO surface. Interactions with a closely located 23Na and a strongly coupled 1H proton were also seen in the HYSCORE spectra but assigned to two different superoxides with various gzz values presented in the sample.
Original languageEnglish (US)
Article number274
JournalInorganics
Volume11
Issue number7
DOIs
StatePublished - Jul 2023

Keywords

  • KOH
  • TiO
  • hydrogen peroxide H O
  • hyperfine coupling
  • pulsed EPR
  • superoxide radical

ASJC Scopus subject areas

  • Inorganic Chemistry

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