TiO(2) suspension exposed to H(2)O(2) in ambient light or darkness: Degradation of methylene blue and EPR evidence for radical oxygen species

The photocatalytic behaviour of TiO(2) has been thoroughly investigated the past years using UV light to photoactivate TiO(2). As this method introduces complications making it difficult to do it economically viable, new pathways to activate TiO(2) have been sought. In the present work, reactive oxy...

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Bibliographic Details
Published in:Applied catalysis. B, Environmental Environmental, 2013-11, Vol.142-143, p.662-667
Main Authors: Sanchez, Luis Dominguez, Taxt-Lamolle, Sebastien Francis Michel, Hole, Eli Olaug, Krivokapic, Andre, Sagstuen, Einar, Haugen, Havard Jostein
Format: Article
Language:English
Subjects:
Catalysis
Darkness
Degradation
Economics
Methylene blue
Radicals
Surface area
Titanium dioxide
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Summary:The photocatalytic behaviour of TiO(2) has been thoroughly investigated the past years using UV light to photoactivate TiO(2). As this method introduces complications making it difficult to do it economically viable, new pathways to activate TiO(2) have been sought. In the present work, reactive oxygen species (ROS) were obtained in a suspension of hydrogen peroxide (H(2)O(2)) and titanium dioxide (TiO(2)) in darkness, offering an alternative method to initiate oxidative behaviour of TiO(2). Methylene blue (MB) degradation was chosen as an indicator for measuring the catalytic effect, allowing for a comparison of the reaction kinetics with other methods to create ROS with TiO(2). The effects of TiO(2) particle effective surface area and concentration of H(2)O(2) were also studied. EPR studies were made to determine the presence of free radicals in the mixture of TiO(2)/H(2)O(2) in darkness. Under the given lighting conditions, the results demonstrate the relevance of the TiO(2) effective surface area and concentration of H(2)O(2) and TiO(2) as parameters influencing the chemical catalysis of MB due to the action of hydroxyl (OH(middle dot)) and/or hydroperoxide radicals (HO(2)(middle dot)).
ISSN:0926-3373