A multi-step mechanism and integrity of titanate nanoribbons†
A one-step hydrothermal treatment of TiO2 powders under strongly basic conditions has been used to synthesize titanate nanoribbons. The nanoparticles were thoroughly characterized using several methods including transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectrometry (XPS) to determine their morphological, structural and chemical characteristics. The influence of the nature and size of the TiO2 precursor and of the reaction duration on the formation of the nanoribbons was investigated. The conditions required to obtain only titanate nanoribbons with a width ranging from 100 to 200 nm and several tens of micrometers in length were determined: the optimum precursor's grain size is about 25 nm and the reaction duration should be at least 20 h. Starting from our experimental results, we propose a multi-step mechanism of formation. In addition, a study of the integrity of the titanate nanoribbon structure reveals that they are made of an assembly of smaller ribbons juxtaposed and piled up on top of one another.