Enhanced photocatalytic activity of TiO2 nanofibers and their flexible composite films: Decomposition of organic dyes and efficient H2 generation from ethanol-water mixtures

Abstract

TiO 2 nanofibers decorated with Pt and Pd nanoparticles have been synthesized and studied in various photocatalytic processes. Excellent photocatalytic behavior in the decomposition of organic dyes in water, degradation of organic stains on the surface of flexible freestanding cellulose/catalyst composite films and in generation of hydrogen from ethanol using both suspended and immobilized catalysts are demonstrated. The performance of the nanofiber-based TiO 2 materials is competitive with-and in some cases outperforms-their conventional nanoparticle-based counterparts. In all cases, Pd-decorated TiO 2 nanoparticles and nanofibers proved to be more efficient than their Pt-based counterparts, which could be explained on the basis of the formation of nano-sized Schottky interfaces at the contacts between TiO 2 and metal nanoparticles. The feasibility of forming cellulose/catalyst composites provides a novel way of utilizing photocatalyst materials in large-area coatings and freestanding films.

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

“…The structure of TiO 2 -B includes nanoscopic channels, which allow advanced ionic transport in these materials as well. Annealing for a longer period of time and/or at higher temperatures result in the formation of bulky TiO 2 anatase (up to 700 1C) and rutile (over 700 1C) phases [35]. Although X-ray diffraction is often used in the literature to reveal the phase composition of the product, due to the very similar diffraction patterns of anatase and TiO 2 -B which show only minor differences in the low angle scattering range, XRD may sometimes be unreliable for analysis.…”

“…Before the carbonylation process the H-form titanate nanowires were thermally treated for 1 h in nitrogen at 773 K. XPS and FT-IR analysis evidenced that the weakly adsorbed water and OH groups were removed during the heat treatment. The ordered TiO 2 anatase structure starts to develop at this temperature [35,92,282]. The detailed physico-chemical characterization of cobalt loaded titanate nanowires will be reported below in the following order: (i) Co 2 (CO) 8 decomposition, (ii) titanate optical properties, (iii) detailed XPS characterization of the system and (iv) product morphology.…”

“…Fig. 35. UV/vis spectra of silver titanate before (black curve) and after solar light irradiation under 250 W (dark gray curve) and 900 W (light gray curve), respectively.…”

“…These 1D titanates may be ionexchanged under mild acidic conditions, and the obtained Htitanates can serve as starting materials for synthesizing various titania phases by simple annealing processes. Upon calcination in air or in inert atmosphere, titanates undergo dehydration and gradual recrystallization into titania nanostructures of similar shape [35,421]. The crystal structure of the forming 1D product is a function of several factors such as the temperature and duration of annealing as well as the concentration of alkaline cations in the original lattice.…”

Structural, Optical and Photocatalytic Properties of Co-Tio2 Prepared by Sol-Gel Technique

“…These phases are characterized with high refractive index, low absorption and low dispersion in visible and near-infrared spectral regions, high chemical and thermal stabilities 3 . Anatase is found to have a highest activity in most studies 4 . The anatase phase TiO 2 has been employed the photo catalytic degradation processes only under the ultra violet (UV) light illumination due to its large band gap (~3.2 eV).…”