Polyvinyl alcohol (PVA) nanofibers reinforced with multi-walled carbon nanotubes (MWCNTs) were fabricated by electrospinning. MWCNTs were introduced into the PVA matrix through the application of an electric field. The morphology of the composite MWCNTs/PVA fibers was characterized by scanning electron microscopy. Results show that the nanofibers had a diameter between 48 and 103 nm and contained a variable amount of MWCNTs. The electrical properties of MWCNTs/PVA nanofibers were investigated by fabricating impedance-type sensors. The impedance and electrical conductivity of the samples were evaluated in the range 46% and 89% relative humidity.

One-dimensional nanostructures have shown high photocatalytic efficiency due to their high surface area to volume ratio and charge transfer efficiency. In this work, we have studied the influence of zinc acetate content (zinc acetate to polyvinyl alcohol (PVA) mass ratio) on the photoelectrochemical performance of zinc oxide (ZnO) nanostructures. The nanostructures of ZnO were fabricated on fluorine-doped tin oxide glass substrate by electrospinning of aqueous solution containing different amounts of zinc acetate. The precursor nanofibers of zinc acetate/PVA were converted into polycrystalline ZnO nanostructures with hexagonal wurtzite crystal structure by calcination at 600°C for 3 h. It was found that by increasing the amount of zinc acetate, the diameter of the as-spun precursor fibers increased and their distribution became broader. The mean diameter of the ZnO nanoparticles forming...

ZnO/TiO2 nanostructures were fabricated by an electrostatically modified electrospinning technique using zinc acetate and commercially available TiO2-P25, polyvinyl alcohol, and a solvent. It was found that the TiO2-P25 nanoparticles were attached to the ZnO nanostructures, and the mean diameter of the nanoparticles forming the nanostructures ranged from 31 to 52 nm with increasing the amount of zinc acetate. The obtained results evidenced that the coupling of TiO2 with ZnO enhanced the IPCE and improved the photocatalytic activity of ZnO. Particularly, the ZnO/TiO2 nanostructures fabricated with a zinc acetate-to-PVA ratio of 2:3 exhibited the highest IPCE and photocatalytic activity.

This work was partially supported by CONCYTEC (Peru) trough the project contract 169-2006-OAJ and ANPCyT (Argentina) PICT 33973. The authors are in debt with the reviewers for their useful suggestions to improve this paper.

TiO2 nanotubes were synthesized by alkaline hydrothermal treatment of TiO2 nanoparticles with a controlled proportion of anatase and rutile. Tailoring of TiO2 phases was achieved by adjusting the pH and type of acid used in the hydrolysis of titanium isopropoxide (first step in the sol-gel synthesis). The anatase proportion in the precursor nanoparticles was in the 3–100% range. Tube-like nanostructures were obtained with an anatase percentage of 18 or higher while flake-like shapes were obtained when rutile was dominant in the seed. After annealing at 400°C for 2 h, a fraction of nanotubes was conserved in all the samples but, depending on the anatase/rutile ratio in the starting material, spherical and rod-shaped structures were also observed.

This work was financially supported by the University of Buenos Aires (UBACyT; TX 117 and X093), ANPCyT (Agencia nacional de Promoción de Ciencia y Tecnología) PICT 10621, the International Program for Physical Science of Uppsala University, Sweden (IPPS), the Research Institute of Universidad Nacional de Ingeniería, the CONCYTEC (Peruvian Research Council), and CYTED network VIII-G.