Search

Inspired by the highly efficient hierarchical structure of plants that use natural light, the hierarchical 'forest-like' TiO2 nanofiber/ZnO nanorod/CuO nanoparticle ternary material 2 is synthesized by a stepwise process: electrospinning of TiO2 nanofibers, hydrothermal growth of ZnO nanorods, and photodeposition of CuO nanoparticles. Material 2 has a higher photodegradation rate of acid orange (AO 7) and stronger antibacterial capability under irradiation with solar light in comparison to that of the hierarchical 'tree-like' TiO2 nanofiber/ZnO nanorod material 1 and one dimensional as-spun TiO2 nanofibers. These enhancements result from the unique hierarchical forest- and tree-like features of materials 1 and 2, which enhance the light absorption capability, increase the specific surface area for mass transfer and bacteria attachment, create more reaction sites, and retard the recombination of photogenerated electrons and holes. A proportional relationship was found between the photocatalytic activity and the hierarchy of the materials. The sizes of the hierarchical nanostructured materials are in the micron range, which provides the opportunity for using these materials in engineering applications. [ABSTRACT FROM AUTHOR]

Abstract: Here we present a simple two-phase assembling method to produce high-quality graphene oxide–TiO2 nanorod composites (GO–TiO2 NRCs) on gram scale. TiO2 nanorods dispersed in toluene are synthesized from a facile two-phase hydrothermal method. The effective attachment of TiO2 nanorods on the whole GO sheets at the water–toluene interface is confirmed by Transmission Electron Microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The as-synthesized TiO2 nanorods show a slightly higher efficiency in the photocatalytic degradation of C. I. Acid Orange 7 (AO 7) irradiated under UV light (λ =254nm) and higher antibacterial activity under simulated sunlight than that of TiO2 nanoparticles with the same diameter. After combined with graphene oxide (GO), the GO–TiO2 NRCs show much higher photocatalytic activities than that of TiO2 nanorods alone and the GO–TiO2 nanoparticle composites (GO–TiO2 NPCs). The ratio of TiO2 and GO has no evident effect on the photocatalytic activity of GO–TiO2 NRCs when all the TiO2 nanorods are anchored on the GO sheets. The higher photocatalytic activity of GO–TiO2 NRCs is ascribed to the anti-charge recombination and the more (101) facets. Considering the superior photocatalytic activity of GO–TiO2 NRCs and the fact that they can been easily mass-produced, we expect this material may find important applications in environmental engineering and other fields. [Copyright &y& Elsevier]