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In this work, we studythe influence of the annealing treatment on the behaviour of titanium dioxidenanotube layers. The heat treatment protocol is actually the key parameter toinduce stable oxide layers and needs to be better understood. Nanotube layerswere prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoricacid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis,coupled with thermogravimetry, gives us an inside on the oxidation behaviour oftitanium dioxide nanotube layers compared to bulk reference samples. Structuralstudies were performed at 700°C for 12 h in order to follow the timeconsequences on the oxidation of the material, in sufficient stabilityconditions. In-situ XRD brought to light that the amorphous oxide layer induced byanodization is responsible for the simultaneous growths of anatase and rutile phaseduring the first 30 minutes of annealing while the bulk sample oxidation leadsto the nucleation of a small amount of anatase TiO2. The initialamorphous oxide layer created by anodization is also responsible for the delayin crystallization compared to the bulk sample. Thermogravimetric analysisexhibits parabolic shape of the mass gain for both anodized and bulk sample; thiskinetics is caused by the formation of a rutile external protective layer, asdepicted by the associated in-situ XRDdiffractograms. We recorded that titanium dioxide nanotube layers exhibit alower mean mass gain than the bulk, because of the presence of an initialamorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layersbehavior during the annealing treatment for the bulk and nanostructured layer. Anatasecrystallites are mainly localized at the interface oxide layer-metal and therutile is at the external interface. Sample surface topography was characterizedusing scanning electron microscopy SEM. As a probe of the photoactivity ofthe annealed TiO2 nanotube layers, degradation of an acid orange 7AO7 dye solution and 4-chlorophenol under UV irradiation at 365 nm wereperformed. Such titanium dioxide nanotube layers show an efficientphotocatalytic activity and the analytical results confirm the degradationmechanism of the 4-chlorophenol reported elsewhere.

KEYWORDS

Titanium Dioxide Nanotubes, In-Situ X-Ray Diffraction, Annealing Treatment, Photo-Degradation

Cite this paper

Siampiringue, M. , Massard, C. , Caudron, E. , Sibaud, Y. , Sarakha, M. and Awitor, K. 2016 Impact of Annealing Treatment on the Behaviour of Titanium Dioxide Nanotube Layers. Journal of Biomaterials and Nanobiotechnology, 7, 142-153. doi: 10.4236-jbnb.2016.73015.





Autor: Marie Siampiringue1, Christophe Massard1*, Eric Caudron1, Yves Sibaud1, Mohammed Sarakha2,3, Komla Oscar Awitor1

Fuente: http://www.scirp.org/



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