An electron spin resonance study of the superoxide radical anion in polycrystalline magnesium oxide and titanium dioxide powders
- 1 January 1988
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
- Vol. 84 (5) , 1723-1728
- https://doi.org/10.1039/f19888401723
Abstract
Treatment of a titanium dioxide polycrystalline powder with hydrogen peroxide produces a paramagnetic species with g1= 2.022, g2= 2.010, g3= 2.003. This radical, observed at atmospheric pressure, is proposed to be subsurface O˙– 2i.e. the superoxide radical anion. The same species, although with different g values; g1= 2.074, g2= 2.007, g3= 2.002, is found for magnesium oxide (MgO) treated with H2O2. Two further sites for O˙– 2 are also indicated by the spectra. Two of these O˙– 2 species, similar to those found for the MgO product, are detected in an untreated mixture of 25% MgO2–75% MgO. The concentration of the O˙– 2 species in this mixture is increased by γ-irradiation.Keywords
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