resumo
Titanate nanotubes (TNTs) with different sodium contents have been synthesised using a hydrothermal approach and a swift and highly controllable post-washing processes. The influence of the sodium/proton replacement on the structural and morphological characteristics of the prepared materials was analysed. Different optical behaviours were observed depending on the Na+/H+. samples' content. A band gap energy of 3.27 +/- 0.03 eV was estimated for the material with higher sodium content while a value of 2.81 +/- 0.02 eV was inferred for the most protonated material, which therefore exhibits an absorption edge in the near visible region. The point of zero charge of the materials was determined and the influence of the sodium content on the adsorption of both cationic and anionic organic dyes was studied. The photocatalytic performance of the TNTs samples was evaluated in the rhodamine 6G degradation process. Best photodegradation results were obtained when using the most protonated material as catalyst, although this material has shown the lowest R6G adsorption capability. (C) 2012 Elsevier B.V. All rights reserved.
palavras-chave
NANOSTRUCTURED TITANATES; HYDROTHERMAL TREATMENT; TIO2; CHARGE; DYES
categoria
Chemistry
autores
Bem, V; Neves, MC; Nunes, MR; Silvestre, AJ; Monteiro, OC
nossos autores
Armando Jorge Domingues Silvestre
Professor Catedrático
Márcia Carvalho Neves
Investigador AuxiliarGrupos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
This work was supported by Fundacao para a Ciencia e Tecnologia (PTDC/CTM-NAN/113021/2009, PEst-OE/QUI/UI0612/2011 and Programme Ciencia 2007). M. C. Neves thank FCT for a research grant(SFRH/BPD/35046/2007). The authors thank P.I. Teixeira for a critical reading of the manuscript.