Novel photocatalyst-based colourimetric indicator for oxygen

A. Mills, D. Hazafy, K. Lawrie

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

The preparation and characterisation of a novel, UV-activated solvent-based, colourimetric indicator for O-2 is described, comprising a redox dye (methylene blue, MB), semiconductor photocatalyst (TiO2), and a sacrificial electron donor (SED), all dispersed/dissolved in a polymer medium (sulfonated polystyrene, SPS). Upon exposure, the indicator is readily photobleached as the MB is converted into its oxygen-sensitive, leuco form, LMB. Unlike its water-based counterpart, the recovery of the original colour is very slow (ca. 5 days cf. 6 min), probably due to the largely hydrophobic nature of the polymer encapsulation medium. The kinetics of film photobleaching appear to fit very well, in terms of: irradiance, [TiO2] and [MB], to the usual Langmuir-Hinshelwood type equation associated with a photocatalytic process. The glycerol appears not only to function as a SED, but also a plasticizer and medium for dye dissolution. The kinetics of colour recovery of the photobleached film appear directly dependent upon the ambient level of O-2 but shows a more complex dependence upon the relative humidity, RH. The photobleached film does not recover any of its colour over a 24 h period if the RH
Original languageEnglish
Pages (from-to)59-63, Impact Factor: 3.9
Number of pages5
JournalCatalysis Today
Volume161
DOIs
Publication statusPublished - 2011

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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