Novel photocatalyst-based colourimetric indicator for oxygen


Autoria(s): Mills, A.; Hazafy, D.; Lawrie, K.
Data(s)

2011

Resumo

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

Identificador

http://pure.qub.ac.uk/portal/en/publications/novel-photocatalystbased-colourimetric-indicator-for-oxygen(3190b407-c2bb-42c4-b01d-aca507986af8).html

http://dx.doi.org/10.1016/j.cattod.2010.10.073

Idioma(s)

eng

Direitos

info:eu-repo/semantics/restrictedAccess

Fonte

Mills , A , Hazafy , D & Lawrie , K 2011 , ' Novel photocatalyst-based colourimetric indicator for oxygen ' Catalysis Today , vol 161 , pp. 59-63, Impact Factor: 3.9 . DOI: 10.1016/j.cattod.2010.10.073

Palavras-Chave #/dk/atira/pure/subjectarea/asjc/1500/1503 #Catalysis #/dk/atira/pure/subjectarea/asjc/1600 #Chemistry(all)
Tipo

article