Publication Type Journal Article
Title Titanate nanotubes sensitized with silver nanoparticles: Synthesis, characterization and in-situ pollutants photodegradation
Authors B. Barrocas C. D. Nunes M. L. Carvalho O. Monteiro
Groups
Journal APPLIED SURFACE SCIENCE
Year 2016
Month November
Volume 385
Number
Pages 18-27
Abstract In this work, titanate nanotubes were modified with silver nanoparticles to produce new nanocomposite materials with enhanced photocatalytic activity for phenol removal. The TNTs were produced using a hydrothermal approach and, after being submitted to an Ag+ exchange process, metallic Ag nanoparticles were obtained over the nanotubes surface. The prepared materials were structural, morphological and optical characterized by X-ray powder diffraction, micro X-ray fluorescence, transmission electron microscopy, diffused reflectance spectroscopy and X-ray photoelectron spectroscopy. The characterization results indicate that Ag+ was immobilized not only in the nanotubes external surface but mainly in the TiO6 interlayers space. The application of this new nanocomposite material on photocatalytic degradation of pollutants was investigated. First, the evaluation of hydroxyl radical formation, using the terephthalic acid as a probe was studied. The photocatalytic activity of the sensitized materials for phenol degradation was afterwards evaluated. The results show that the nanocomposite sample is the best catalyst, achieving 98.0\% photodegradation efficiency of a 0.2 mM phenol solution within 20 min under UV-vis radiation. The reusability of the prepared samples as photocatalysts was evaluated in four successive degradation assays, using fresh phenol solutions. The sensitized sample demonstrated excellent catalytic reusability ability, without loss of photochemical stability. The structural and morphological characterization during these experiments revealed no modifications on the nanotubes morphology but a continuous increase on the Ag nanoparticles, in number and size, with the irradiation time. A mechanism for this continuous growth of the Ag nanoparticles, together with the phenol catalytic photodegradation, over the nanotubes surface, is proposed and discussed. (C) 2016 Elsevier B.V. All rights reserved.
DOI http://dx.doi.org/10.1016/j.apsusc.2016.05.080
ISBN
Publisher
Book Title
ISSN 0169-4332
EISSN 1873-5584
Conference Name
Bibtex ID ISI:000380825900003
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