Photocatalytic oxidation of propene at low concentration

The present paper analyses the preparation and characterisation of different titanium dioxide-based photocatalysts for propene oxidation at low concentration. Special attention has been paid to the agglomeration of the photocatalysts in form of pellets, to the study of the effect of introducing some carbonaceous materials into the catalyst composition and to comparison with commercial photocatalysts. Our results show that P25 exhibits the best activity among all the studied materials. However, activity importantly decreases when agglomerating the photocatalysts in form of pellets, either with or without carbon addition. The type of carbon material used in the photocatalyst strongly affects propene activity. Thus, carbon materials combining high surface area and high electric conductivity enhance the photocatalyst performance and photocatalyst pellets have been prepared exceeding the activity of a carbon-containing commercial photocatalyst. The importance of the UV-source has been highlighted, showing the 257.7 nm peak radiation much better results than the 365 nm UV-light. The studied photocatalysts are very interesting for propene oxidation not only because of their high activity, but also because it remains constant for more than 40 h and total mineralization of the oxidised propene to carbon dioxide and water is achieved. (C) 2006 Elsevier B.V. All rights reserved.