Characterization and thermal stability of cobalt-modified 1-D nanostructured trititanates

Journal Article · Thu Jan 15 00:00:00 EST 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.10.008· OSTI ID:21212174

Morgado, Edisson ^[1]; Marinkovic, Bojan A; Jardim, Paula M ^[2]; Rizzo, Fernando C ^[2]

---

1. PETROBRAS S.A./CENPES, Research and Development Centre, Av. Horacio Macedo, 950, Cidade Universitaria, 21941-915 Rio de Janeiro-RJ (Brazil)
2. Department of Materials Science and Metallurgy, Pontifical Catholic University, C.P.: 38008, 22453-900 Rio de Janeiro-RJ (Brazil)

One-dimensional (1-D) nanostructured sodium trititanates were obtained via alkali hydrothermal method and modified with cobalt via ion exchange at different Co concentrations. The resulting cobalt-modified trititanate nanostructures (Co-TTNS) were characterized by TGA, XRD, TEM/SAED, DRS-UV-Vis and N{sub 2} adsorption techniques. Their general chemical formula was estimated as Na{sub x}Co{sub y/2}H{sub 2-x-y}Ti{sub 3}O{sub 7}.nH{sub 2}O and they maintained the same nanostructured and multilayered nature of the sodium precursor, with the growth direction of nanowires and nanotubes along [010]. As a consequence of the Co{sup 2+} incorporation replacing sodium between trititanate layers, two new diffraction lines became prominent and the interlayer distance was reduced with respect to that of the precursor sodium trititanate. Surface area was slightly increased with cobalt intake whereas pore size distribution was hardly affected. Besides, Co{sup 2+} incorporation in trititanate crystal structure also resulted in enhanced visible light photon absorption as indicated by a strong band-gap narrowing. Morphological and structural thermal transformations of Co-TTNS started nearly 400 deg. C in air and the final products after calcination at 800 deg. C were found to be composed of TiO{sub 2}-rutile, CoTiO{sub 3} and a bronze-like phase with general formula Na{sub 2x}Ti{sub 1-x}Co{sub x}O{sub 2}. - Graphical abstract: Co{sup 2+} incorporation in 1D-trititanate crystal nanostructure (Co-TTNS) causes reduction in interlayer distance by comparison with its sodium precursor (Na-TTNS) and leads to enhanced visible light photon absorption efficiency due to a strong band-gap narrowing.

• OSTI ID: 21212174
• Journal Information: Journal of Solid State Chemistry, Vol. 182, Issue 1; Other Information: DOI: 10.1016/j.jssc.2008.10.008; PII: S0022-4596(08)00514-8; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
CALCINATION
COBALT COMPOUNDS
COBALT IONS
CRYSTAL STRUCTURE
ELECTRON DIFFRACTION
HYDROTHERMAL SYNTHESIS
ION EXCHANGE
LAYERS
NANOTUBES
QUANTUM WIRES
RUTILE
SODIUM COMPOUNDS
SURFACE AREA
THERMAL GRAVIMETRIC ANALYSIS
TITANATES
TITANIUM OXIDES
X-RAY DIFFRACTION