Raman and electrochemical impedance studies of sol-gel titanium oxide and single walled carbon nanotubes composite films.
Titanium oxide grown by a sol-gel route on single-walled carbon nanotubes was studied by Raman and Electrochemical Impedance techniques and compared with mixtures obtained by mechanical grinding. In spite of the superior dispersion of single-walled carbon nanotubes bundles in sol-gel composites, the lost of the small-diameter carbon nanotubes in the oxidizing sol-gel bath was inferred from their Raman spectra and the lower capacitive current of the voltammograms in 0.1 M H2SO4. We proposed proton electrosorption as the main charge storage mechanism for sol-gel composites, favoured by the hydroxylation and n-type conductivity of the oxide, while electrodes based on mixtures were dominated by double-layer charging, developing some pseudocapacitance with potential cycling due to the reversible oxidation of carbon nanotubes. Comparsion with TiO2/Carbon Blacks composites shows the effective role of single-walled carbon nanotubes as templates to control the mesoporous nature of sol-gel composite electrodes.
Rincón
M E
ME
Centro de Investigación en Energía-UNAM, Apartado Postal 34, Temixco 62580, MOR, México.
Trujillo-Camacho
M E
ME
Miranda-Hernández
M
M
Cuentas-Gallegos
A K
AK
Orozco
G
G
D017097:Electric Impedance; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D005782:Gels; D008422:Materials Testing; D053768:Metal Nanoparticles; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D044367:Phase Transition; D013059:Spectrum Analysis, Raman / Q000379:methods*; D014025:Titanium / Q000737:chemistry*
D005782:Gels; D037742:Nanotubes, Carbon; D010087:Oxides; C009495:titanium dioxide; D014025:Titanium