Micro-Raman analysis of titanium oxide/carbon nanotubes-based nanocomposites for hydrogen sensing applications

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.08.018· OSTI ID:21421493

Santangelo, S ^[1]; Messina, G; Faggio, G; Donato, A; De Luca, L ^[1]; Donato, N ^[2]; Bonavita, A; Neri, G ^[3]

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1. Department of Mechanics and Materials, 'Mediterranea' University of Reggio Calabria, I-89122 Reggio Calabria (Italy)
2. Department of Matter Physics and Electronic Engineering, University of Messina, I-98166 Messina (Italy)
3. Department of Industrial Chemistry and Materials Engineering, University of Messina, I-98166 Messina (Italy)

Titanium oxide/carbon nanotubes-based nanocomposites (TiO{sub 2}/CNTs, prepared by sol-gel method, and 2%Pt/TiO{sub 2}/CNTs, obtained by wetness impregnation of the TiO{sub 2}/CNTs base material with a solution of platinum acetylacetonate) have been recently used as active layer in hydrogen sensing devices at near room temperature, obtaining quite different responsiveness. The microstructure of these hybrid materials is here systematically investigated by micro-Raman spectroscopy at 2.41 eV. The results show that regardless of the nominal C/Ti molar ratio (3.6 or 17.0) only the anatase phase of titania is formed. Theoretical calculations demonstrate that phonon confinement is fully responsible for the large blue-shift ({approx}10 cm{sup -1}) and broadening ({approx}20 cm{sup -1}) of the lowest-frequency Raman mode with respect to bulk anatase. The average size (4.3-5.0 nm) of TiO{sub 2} crystallites, resulting from Raman spectra fitting, is in excellent agreement with those inferred from transmission electron microscopy and X-ray diffraction measurements. - Graphical Abstract: Micro-Raman analysis of TiO{sub 2}/CNTs and Pt/TiO{sub 2}/CNTs hybrids for H{sub 2} sensing applications evidences that regardless of C/Ti molar ratio titania crystallizes in the anatase phase. The very small size of TiO{sub 2} crystallites (4.3-5.0 nm) is responsible for the observed phonon confinement effects.

• OSTI ID: 21421493
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 10; Other Information: DOI: 10.1016/j.jssc.2010.08.018; PII: S0022-4596(10)00352-X; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
CARBON
COMPOSITE MATERIALS
EV RANGE 01-10
HYDROGEN
NANOTUBES
PLATINUM
PLATINUM COMPOUNDS
RAMAN SPECTRA
RAMAN SPECTROSCOPY
SOL-GEL PROCESS
TEMPERATURE RANGE 0273-0400 K
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
ENERGY RANGE
EV RANGE
LASER SPECTROSCOPY
MATERIALS
METALS
MICROSCOPY
NANOSTRUCTURES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
SCATTERING
SPECTRA
SPECTROSCOPY
TEMPERATURE RANGE
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS