Publication date:
1 November 2016
Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 330
Author(s): Andrew Mills, Nathan Wells, Christopher O’Rourke
The initial rate of the photocatalysed oxidation of methylene blue, MB, by dissolved oxygen in solution, ri(MB), is measured for a series of titania on glass samples exhibiting a wide range of activities. The samples used include two different types of commercial self-cleaning glass and a lab-made sol-gel titania film. The activities of these samples are also assessed using a resazurin-based photocatalyst activity indicator ink, i.e. Rz paii, for which the initial rates of the photocatalysed reduction of Rz were measured, ri(Rz). A plot of ri(MB) vs. ri(Rz) reveals a good straight line, thereby demonstrating a linear correlation (for TiO2 films on glass at least) between the slow (usually hours) photocatalysed oxidation of organic materials, such as MB, and the fast (typicallymin) photocatalysed irreversible reduction of a dye, like Rz, in a paii. The possible use of paii technology for assessing, in a simple, quick and inexpensive manner, photocatalytic films both in the laboratory and in situ is discussed briefly.