Novel photocatalyst-based colourimetric indicator for oxygen: Use of a platinum catalyst for controlling response times


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

2011

Resumo

The preparation and characterisation of a novel, UV-activated, solvent-based, colourimetric indicator for oxygen is described, comprising a redox dye (methylene blue, MB), semiconductor photocatalyst (Pt-TiO2), and a sacrificial electron donor (SED = glycerol), all dispersed/dissolved in a polymer medium (sulfonated polystyrene. SPS). Upon exposure to UVA light, the Pt-TiO2/MB/glycerol/SPS oxygen indicator is readily photobleached as the MB is converted into its oxygen-sensitive, leuco form, LMB. In contrast to its non-platinised TiO2 counterpart (TiO2/MB/glycerol/SPS oxygen indicator), the recovery of the original colour is faster (ca. 1.5 days cf. 5 days at 21 degrees C). This is due to the catalytic action of the 0.38 wt% platinum loaded onto the semiconductor photocatalyst. TiO2, on the oxidation of the photogenerated LMB by ambient O-2. Furthermore, by increasing the level of platinum loading, recovery times can be decreased further; e.g. a Pt-TiO2/MB/glycerol/SPS oxygen indicator with platinum level of 1.52 wt% recovers fully within 12 h. A study of the kinetics of recovery as a function of film thickness revealed the recovery step is not controlled by the diffusion of O-2 through the film, but instead dependent upon the slow rate of oxidation of LMB to MB by O-2 in the low dielectric polymer encapsulation medium. Other work showed this recovery is only moderately dependant upon temperatures above -10 degrees C and very sensitive to relative humidity above 30% RH. Potential uses of this UV light activated indicator are discussed briefly. (C) 2011 Elsevier B.V. All rights reserved.

Identificador

http://pure.qub.ac.uk/portal/en/publications/novel-photocatalystbased-colourimetric-indicator-for-oxygen-use-of-a-platinum-catalyst-for-controlling-response-times(44d8117f-70a2-4b22-8d6b-485fec89ff73).html

http://dx.doi.org/10.1016/j.snb.2011.05.029

Idioma(s)

eng

Direitos

info:eu-repo/semantics/restrictedAccess

Fonte

Mills , A & Lawrie , K 2011 , ' Novel photocatalyst-based colourimetric indicator for oxygen: Use of a platinum catalyst for controlling response times ' SENSORS AND ACTUATORS B-CHEMICAL , vol 157 , pp. 600-605, Impact Factor: 4.1 . DOI: 10.1016/j.snb.2011.05.029

Palavras-Chave #/dk/atira/pure/subjectarea/asjc/3100/3105 #Instrumentation #/dk/atira/pure/subjectarea/asjc/2500/2505 #Materials Chemistry #/dk/atira/pure/subjectarea/asjc/2500/2508 #Surfaces, Coatings and Films #/dk/atira/pure/subjectarea/asjc/2500/2506 #Metals and Alloys #/dk/atira/pure/subjectarea/asjc/2500/2504 #Electronic, Optical and Magnetic Materials #/dk/atira/pure/subjectarea/asjc/3100/3104 #Condensed Matter Physics #/dk/atira/pure/subjectarea/asjc/2200/2208 #Electrical and Electronic Engineering
Tipo

article