Design of liquid-crystalline aqueous suspensions of rutile nanorods: Evidence of anisotropic photocatalytic properties
Résumé
TiO2 rutile nanorods of average length L = 160 ± 40 nm and average diameter D = 15 ± 5 nm have been synthesized through a seed-mediated growth process by TiCl4 hydrolysis in concentrated acidic solution. These nanorods were dispersed in water to yield stable (aggregation-free) colloidal aqueous suspensions. At volume fractions φ > 3%, the suspensions spontaneously display a phase separation into an isotropic liquid phase and a liquid-crystalline phase identified as nematic by X-ray scattering. At φ > 12%, the suspensions form a nematic single phase, with large order parameter, S = 0.75 ± 0.05. Very well aligned rutile films on glass substrate were produced by spin-coating, arid their photocatalytic properties were examined by monitoring the decomposition of methylene blue under UV light. We found that UV-light polarized along the quadratic axis of the rutile nanorods was most efficient for this photocatalytic reaction.
Mots clés
- polarization
- photocatalysis
- radiation scattering
- suspension
- synthesis
- ultraviolet radiation
- Methylene blue
- Photocatalytic properties
- Rutile
- Rutile films
- Nanorods
- Titanium dioxide
- Suspensions (fluids)
- Spin coating
- Photocatalysis
- Nematic liquid crystals
- Hydrolysis
- Crystal growth
- article
- glass
- methylene blue
- nanorod
- titanium dioxide
- titanium tetrachloride
- water
- acidity
- anisotropy
- aqueous solution
- X ray scattering
- biofilm
- colloid
- decomposition
- dispersion
- hydrolysis
- liquid
- liquid crystal
- monitoring
- phase separation