An EPR study of thermally and photochemically generated oxygen radicals on hydrated and dehydrated titania surfaces

An EPR study of thermally and photochemically generated oxygen radicals on hydrated and... The formation of a series of oxygen-centred radicals on different TiO2 samples (P25 and two different rutile materials) under various conditions was investigated using X-band c.w. Electron Paramagnetic Resonance (EPR) spectroscopy. The radicals were formed either on thermally-reduced TiO2, or by UV irradiation of the oxide under an oxygen atmosphere. The nature and stability of the radicals was also explored as a function of surface hydration. On thermally reduced TiO2, containing surface and bulk Ti3+ centres, oxygen adsorption at 300 K results in the preferential formation and stabilisation of O2 - anions on the P25 surface, but O- and O3 - anions are generated on the rutile surfaces. Superoxide anions (O-) and trapped holes (O2 -) were also identified after photo-irradiation of the thoroughly dehydrated TiO2 samples under oxygen. The O- anions were only visible at low temperatures under continuous irradiation, while the O2 - anions were stable for days at 300 K. By comparison, on fully hydrated surfaces, no stable oxygen centred radicals could be detected on P25, while O2 - anions were easily observed on the rutile surfaces. On partially hydrated P25, the O-, O2 - and HO2 anions were detected after UV irradiation at 77 K; all radicals decayed upon warming to 298 K. On partially hydrated rutile, the O- and O2 - anions were detected and, unlike the case for P25, were found to be stable for days under the same conditions. The results illustrate the varied formation and stability of the oxygen centred radicals on TiO2 surfaces depending on the pretreatment conditions. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Research on Chemical Intermediates Springer Journals

An EPR study of thermally and photochemically generated oxygen radicals on hydrated and dehydrated titania surfaces

Loading next page...
 
/lp/springer_journal/an-epr-study-of-thermally-and-photochemically-generated-oxygen-OTx0ESuwIM
Publisher
Brill Academic Publishers
Copyright
Copyright © 2003 by VSP 2003
Subject
Chemistry; Inorganic Chemistry; Physical Chemistry
ISSN
0922-6168
eISSN
1568-5675
D.O.I.
10.1163/156856703322148991
Publisher site
See Article on Publisher Site

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches

$49/month

Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

$588

$360/year

billed annually
Start Free Trial

14-day Free Trial