Morphological control of TiO2 anatase nanoparticles: What is the good surface property to obtain efficient photocatalysts?

Abstract

International audienceThe richness of titanium dioxide sol–gel syntheses described in literature provided a set of four different morphologies of pure anatase nanoparticles to study the impact of the exposed surfaces on the photocatalytic efficiency of the corresponding material. The selection of the experimental parameters such as the temperature, the heating method or organic additives allowed the synthesis of pure anatase materials with significantly different shapes. A thorough microscopic study of these particles gave the exposed crystallographic faces. The photocatalytic activity of the different materials was estimated following the degradation of the rhodamine B dye under UV-light and significantly different behaviors were observed. In the applied photodegradation conditions, two samples were shown to be more efficient than the reference photocatalyst P25. The rationalization of these results was done through the study of the oxide surface properties, using FT-IR spectroscopy with pyridine as a surface probe and the EPR analysis of photogenerated radicals under UV light. The most efficient photocatalyst for rhodamine B degradation was found to be the morphology presenting the stronger acidic surface sites

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