Structural resistance of chemically modified 1-D nanostructured titanates in inorganic acid environment

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2010.06.014· OSTI ID:22066226

Fredholm, Yann C ^[1]; Morgado, Edisson ^[2]; Jardim, Paula M; Rizzo, Fernando ^[3]

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1. Nanogavea-Nanotecnologia Sustentavel Ltda, Av. Padre Leonel Franca 150, Gavea, RJ (Brazil)
2. PETROBRAS S.A./CENPES, Research and Development Centre, Av. Horacio Macedo, 950, Cidade Universitaria, 21941-915, Rio de Janeiro, RJ (Brazil)
3. Departamento de Engenharia de Materiais, Pontificia Universidade Catolica de Rio de Janeiro-PUC-Rio, Rua Marques de Sao Vicente 225, Gavea, RJ (Brazil)

Sodium containing one-dimensional nanostructured layered titanates (1-D NSLT) were produced both from commercial anatase powder and Brazilian natural rutile mineral sands by alkali hydrothermal process. The 1-D NSLT were chemically modified with proton, cobalt or iron via ionic exchange and all products were additionally submitted to intensive inorganic acid aging (pH = 0.5) for 28 days. The morphology and crystal structure transformations of chemically modified 1-D NSLT were followed by transmission electron microscopy, powder X-ray diffraction, selected area electron diffraction and energy dispersive spectroscopy. It was found that the original sodium rich 1-D NSLT and cobalt substituted 1-D NSLT were completely converted to rutile nanoparticles, while the protonated form was transformed in a 70%-30% (by weight) anatase-rutile nanoparticles mixture, very similar to that of the well-known TiO{sub 2}-photocatalyst P25 (Degussa). The iron substituted 1-D NSLT presented better acid resistance as 13% of the original structure and morphology remained, the rest being converted in rutile. A significant amount of remaining 1-D NSLT was also observed after the acid treatment of the product obtained from rutile sand. The results showed that phase transformation of NSLT into titanium dioxide polymorph in inorganic acid conditions were controllable by varying the exchanged cations. Finally, the possibility to transform, through acid aging, 1-D NSLT obtained from Brazilian natural rutile sand into TiO{sub 2}-polymorphs was demonstrated for the first time to the best of authors' knowledge, opening path for producing TiO{sub 2}-nanoproducts with different morphologies through a simple process and from a low cost precursor.

• OSTI ID: 22066226
• Journal Information: Materials Characterization, Vol. 61, Issue 10; Other Information: Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
AGING
COBALT
CRYSTAL STRUCTURE
ELECTRON DIFFRACTION
HYDROTHERMAL SYNTHESIS
INORGANIC ACIDS
IRON
MORPHOLOGY
NANOTUBES
PHASE TRANSFORMATIONS
POWDERS
RUTILE
SODIUM
TITANATES
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY