A step forward towards the structural characterization of Na2Ti2O5·H2O nanotubes and their correlation with optical and electric transport properties

NANOTECNOLOGIA

NAN0TUBOS DE SODIO

TRANSFORMADA DISCRETA DE FOURIER

CARACTERIZACION OPTICA

CARACTERIZACION ELECTRICA

BIBLIOGRAFIA NACIONAL QUIMICA

2020

In this work we present the synthesis, structural, morphological, optical and electrochemical characterization of sodium titanate nanotubes (NaNT) obtained by hydrothermal means. According to our detailed structural study, we found that a Na2Ti2O5·H2O layered crystalline phase with [TiO5] pyramidal square base coordination, utilized as a building block of the nanotubes, explains satisfactorily the experimental results. This is a very important aspect, since the bibliography does not always provide structural information about titanate nanotubes. With respect to the formation mechanism we highlight the crucial role of the post treatment washing in the final crystalline structure of the nanotubes. Simulated X-rays powder diffraction patterns (XRPD), based on real size nanotubes models, were refined with experimental data. Building blocks for the NaNT model were inferred from computational simulations, by means of Density Functional Theory. The obtained tube's model characteristic dimensions were also consistent with SAXS and TEM analysis. In addition, our SAXS analysis suggested that the presence of humidity in the cavities of titanate nanotubes is progressively lost at the 80–100 °C temperature range, in good agreement with thermogravimetric analysis. Electrochemical impedance spectroscopy analysis for dried samples in the temperature range, studied under cooling conditions, revealed a single ionic transport mechanism, probably associated to the in-between [TiO5] layers ion transport. However, a secondary process was observed for non-dried samples, during heating conditions, that could be associated to the ionic transport along the water filled tube's cavity, consistent with SAXS analysis. In summary, this work shows an integral approach, through theory and experiment, in order to understand the effect of the structure on the physical and electronic properties of the system.

Ceramics International v.46, 2020. -- p. 2877-2876

Elsevier

2020

Información sobre Derechos de Autor (Por favor lea este aviso antes de abrir los documentos u objetos) La legislación uruguaya protege el derecho de autor sobre toda creación literaria, científica o artística, tanto en lo que tiene que ver con sus derechos morales, como en lo referente a los derechos patrimoniales con sujeción a lo establecido por el derecho común y las siguientes leyes (LEY 9.739 DE 17 DE DICIEMBRE DE 1937 SOBRE PROPIEDAD LITERARIA Y ARTISTICA CON LAS MODIFICACIONES INTRODUCIDAS POR LA LEY DE DERECHO DE AUTOR Y DERECHOS CONEXOS No. 17.616 DE 10 DE ENERO DE 2003, LEY 17.805 DE 26 DE AGOSTO DE 2004, LEY 18.046 DE 24 DE OCTUBRE DE 2006 LEY 18.046 DE 24 DE OCTUBRE DE 2006) ADVERTENCIA - La consulta de este documento queda condicionada a la aceptación de las siguientes condiciones de uso: Este documento es únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con fines de lucro. Esta reserva de derechos afecta tanto los datos del documento como a sus contenidos. En la utilización o cita de partes debe indicarse el nombre de la persona autora.

Pdf

Inglés

Artículo

DOI: 10.1016/j.ceramint.2019.09.281

Pdf